Efficient high performance demodulation of low bt value gaussian minimum shift keying incorporating turbo equalization

Systems ( 600 ) and methods ( 100 ) for demodulating a Gaussian Filtered Minimum Shift Keyed (GMSK) signal. The GMSK signal is defined in a transmitted symbol domain where each symbol is given by a product of a current data bit and a previous data bit. The GMSK signal is converted from the transmitted symbol domain to a data symbol domain. The conversion is achieved by approximating filtered complex output signals that would be produced by matched filters having filter shapes corresponding to pulses used in terms of a Laurent expansion. Subsequent to the convention of the GMSK signal, a trellis equalization of the GMSK signal is performed exclusively in the data symbol domain based on the terms of the Laurent expansion.

Transceiver Architecture and Methods for Demodulating and Transmitting Phase Shift Keying Signals

A transceiver is described. The transceiver includes a first injection-locked oscillator and a second injection-locked oscillator. The transceiver also includes a first phase-locked loop coupled with the first injection-locked oscillator. The first phase-locked loop is configured to generate a first frequency reference. Further, the transceiver includes a second phase-locked loop coupled the second injection-locked oscillator. The second phase-locked loop is configured to generate a second frequency reference. The transceiver includes a mixer configured to receive the first phase-locked loop output and configured to receive said second injection-locked oscillator output. The mixer is also configured to generate a carrier frequency signal based on the first injection-locked oscillator output and the second injection-locked oscillator output. And, the transceiver includes a modulator configured to receive said carrier frequency signal. 1. A transceiver comprising:a first injection-locked oscillator having a first input configured to receive a binary phase shift keying (“BPSK”) signal and a second input configured to receive a first frequency reference, said first injection-locked oscillator configured to generate a first injection-locked oscillator output;a second injection-locked oscillator having a third input configured to receive said BPSK signal and a fourth input configured to receive a second frequency reference, said second injection-locked oscillator configured to generate a second injection-locked oscillator output;a first phase-locked loop coupled with said second input of said first injection-locked oscillator, said first phase-locked loop configured to generate said first frequency reference;a second phase-locked loop coupled with said fourth input of said second injection-locked oscillator, said second phase-locked loop configured to generate said second frequency reference;a mixer configured to receive said first phase-locked loop output and configured ...

Method and apparatus for channel estimation

Methods and apparatuses for channel estimation are disclosed. The method includes: converting −1's in a local Barker code to 0's; receiving a first preamble symbol output from a first Barker correlator and a second preamble symbol output from a second Barker correlator with a symbol determination module, the first preamble symbol being adjacent to the second preamble symbol; multiplying a result output from the symbol determination module with a correlation result output from the cyclic Barker correlator by using a multiplication module so as to obtain a channel estimation response; and receiving channel estimation responses with a time-domain channel data storage unit, and averaging them to obtain a noise-reduced channel estimation response. The channel estimation method and apparatus of the present invention can be achieved based on few hardware resources and low computation complexity.

REFERENCE SIGNAL SENDING METHOD, REFERENCE SIGNAL RECEIVING METHOD, AND APPARATUS

Embodiments of the present invention provide a reference signal sending method, a reference signal receiving method, and an apparatus. A reference signal sending method includes: obtaining a reference signal sequence, where the reference signal sequence includes multiple bits and exclusive OR of every two bits separated by one bit in the multiple bits is 1; performing Gaussian Minimum Shift Keying GMSK modulation on the reference signal sequence; and sending a modulated reference signal sequence. In the embodiments of the present invention, a reference signal sequence is designed as a sequence in which exclusive OR of every two bits separated by one bit is 1, GMSK modulation is performed on the reference signal sequence, and the same reference signal sequence is used to perform channel estimation during GMSK demodulation. Compared with a case in which a pseudo random sequence is used as a pilot symbol, channel estimation accuracy is improved. 1. A reference signal sending method comprising:obtaining a reference signal sequence, wherein the reference signal sequence comprises multiple bits and exclusive OR of every two bits separated by one bit in the multiple bits is 1;performing Gaussian Minimum Shift Keying (GMSK) modulation on the reference signal sequence; andsending a modulated reference signal sequence.2. The method according to claim 1 , wherein the reference signal sequence is at least one of the following sequences: a first reference signal sequence claim 1 , a second reference signal sequence claim 1 , a third reference signal sequence claim 1 , or a fourth reference signal sequence claim 1 , whereinthe first reference signal sequence is a periodic sequence of a sequence 0, 0, 1, 1, the second reference signal sequence is a periodic sequence of a sequence 0, 1, 1, 0, the third reference signal sequence is a periodic sequence of a sequence 1, 0, 0, 1, and the fourth reference signal sequence is a periodic sequence of a sequence 1, 1, 0, 0.3. The method ...

Method and a device for decoding differentially modulated symbols

A method for decoding differentially modulated received symbols, the differentially modulated received symbols corresponding to a transmission of a differentially modulated version of a codeword out of a set of possible codewords, the received symbols being transferred onto resources of a channel, the resources being equally spaced. A receiver, for each possible codeword: obtains a vector of differentially demodulated symbols by differentially demodulating the differentially modulated received symbols obtained by combining two consecutive differentially modulated received symbols; calculates the product of each differentially demodulated symbol by the conjugate of the element of the codeword having the same rank within the codeword as the differentially demodulated received symbol; calculates the sum of the products; decodes the vector of differentially demodulated symbols by selecting the codeword for which the sum of the products is the maximum.

RADIO COMMUNICATION

A radio transmitter () comprises an encoder () that receives one or more variable message bits, and encodes each message bit that has a first value as a predetermined first binary chip sequence and encodes each message bit that has the opposite value as a predetermined second binary chip sequence. The radio transmitter () transmits data packets, each comprising (i) a predetermined synchronisation portion, comprising one or more instances of the first binary chip sequence, and (ii) a variable data portion, comprising one or more encoded message bits output by the encoder. A radio receiver () receives such data packets. It uses the synchronisation portion of a received data packet to perform a frequency and/or timing synchronisation operation, and then decodes message bits from the data portion of the data packet. 1. A radio transmitter comprising an encoder configured to receive one or more variable message bits and to encode each message bit that has a first value as a predetermined first binary chip sequence and to encode each message bit that has the opposite value as a predetermined second binary chip sequence , wherein the radio transmitter is configured to transmit data packets , each comprising (i) a predetermined synchronisation portion , comprising one or more instances of the first binary chip sequence , and (ii) a variable data portion , comprising one or more encoded message bits output by the encoder.2. A radio transmitter as claimed in claim 1 , configured to modulate the synchronisation portion and the variable data portion on a radio carrier wave using Gaussian frequency-shift-keying (GFSK).3. A radio transmitter as claimed in claim 2 , wherein the GFSK modulation has a modulation index of approximately 0.5.4. A radio transmitter as claimed in claim 1 , wherein one or each of the first and second binary chip sequences is an even number of bits long claim 1 , greater than or equal to four.5. A radio transmitter as claimed in claim 1 , wherein the first ...

Digital system for estimating signal non-energy parameters using a digital Phase Locked Loop

A digital system of measuring parameters of the signal (phase, frequency and frequency derivative) received in additive mixture with Gaussian noise. The system is based on the use of variables of a PLL for calculating preliminary estimates of parameters and calculating the corrections for these estimates when there is a spurt frequency caused by a receiver motion with a jerk. A jerk is determined if the low pass filtered signal of the discriminator exceeds a certain threshold. The jerk-correction decreases the dynamic errors. Another embodiment includes a tracking filter for obtaining preliminary estimates of parameters to reduce the fluctuation errors. Estimates are taken from the tracking filter when there is no jerk and from the block of jerk-corrections when there is a jerk. 1. A system for estimating parameters of an input signal , the system comprising: [{'sub': 'i', 'sup': 'd', 'i) a phase discriminator that determines a phase difference zbetween the input signal and reference signals from a Numerically Controlled Oscillator (NCO); and'}, {'sub': c', 'i', 'i, 'sup': r', 'r, 'ii) a loop filter with a control period Tthat generates a phase control signal φfor the NCO and a frequency control signal ffor the NCO; and'}], 'a) a digital phase locked loop that includes{'sub': 'i', 'sup': 'NCO', 'claim-text': {'br': None, 'sub': i', 'i-1', 'i', 'φ', 'i-1', 'ω', 'c, 'sup': NCO', 'NCO', 'r', 'NCO', 'NCO, 'i': +f', '·T, 'φ=φ+φ·Δ·Δ,'}, 'b) a block for calculation of full phase φaccording to'}{'sub': φ', 'ω, 'sup': NCO', 'NCO, 'where Δis a phase step size in the NCO, and Δis a frequency step size in the NCO;'}{'sub': i', 'i, 'sup': d', 'A, 'c) a low-pass filter inputting the phase difference zand outputting z;'}{'sub': 'i', 'sup': 'NCO', 'claim-text': [{'sub': 'i', 'sup': 'c,E', 'a preliminary estimate {circumflex over (φ)}for a phase of the input signal, and'}, {'sub': 'i', 'sup': 'c,E', 'a preliminary estimate {circumflex over (ω)}for a frequency of the input signal ...

SHARING HARDWARE RESOURCES BETWEEN D-PHY AND N-FACTORIAL TERMINATION NETWORKS

A termination network for a receiver device is provided to support both D-PHY signaling and N-factorial signaling. The first end of each of a plurality dynamically configurable switches is coupled to a common node. A first end of each of a plurality of resistances is coupled to a second end of a corresponding switch. A plurality of terminals receive differential signals and each terminal is coupled to a corresponding second end of a resistance. Each of a plurality differential receivers is coupled between two terminals of the termination network, wherein a first differential receiver and a second differential receiver are coupled to the same two terminals, the first differential receiver is used when the differential signals use a first type of differential signal encoding, the second differential receiver is used when the differential signals use a second type of differential signal encoding. 1. A termination network for a receiver device , comprising:{'b': 844', '849, 'i': a', 'd, 'a plurality dynamically configurable switches (-), a first end of each switch coupled to a common node ();'}{'b': 848', '848', '844, 'i': a', 'd, 'a plurality of resistances (), a first end of each resistance () coupled to a second end of a corresponding switch (-);'}{'b': 811', '811', '848, 'a plurality of terminals (), each terminal () coupled to a corresponding second end of a resistance ();'}{'b': 820', '821', '822', '823', '820', '821', '822', '823', '820', '821', '822', '823', '820', '822', '820', '822, 'i': a', 'a', 'b', 'b, 'a plurality differential receivers (, , , ), each receiver (, , , ) coupled between two terminals of the plurality of terminals, wherein a first subset of differential receivers (, , , ) are used for a first type of differential signal encoding and a second subset of differential receivers (, ) are used for a second type of differential signal encoding, and at least a first differential receiver (, ) is shared by both the first and second sets of ...

METHOD FOR SELECTION BETWEEN VAMOS RECEIVER AND NON-VAMOS RECEIVER IN USER EQUIPMENT

An apparatus and a method are provided for selecting a receiver in a user equipment (UE). The method includes receiving, at the UE, a signal; determining, at the UE, a switch metric based on correlation metrics of a training sequence of the signal; comparing, at the UE, the switch metric with a threshold; and selecting, at the UE, one of a voice services over adaptive multi-user channels on one slot (VAMOS) receiver and a non-VAMOS receiver based on the comparing result. 1. A method for selecting a receiver in a user equipment (UE) , the method comprising:receiving, at the UE, a signal;determining, at the UE, a switch metric based on correlation metrics of a training sequence of the signal;comparing, at the UE, the switch metric with a threshold; andselecting, at the UE, one of a voice services over adaptive multi-user channels on one slot (VAMOS) receiver and a non-VAMOS receiver based on the comparing result.2. The method of claim 1 , wherein selecting the one of the VAMOS receiver and the non-VAMOS receiver comprises:selecting the VAMOS receiver when the switch metric is greater than or equal to the threshold; andselecting the non-VAMOS receiver when the switch metric is less than the threshold.3. The method of claim 1 , wherein determining the switch metric comprises:generating a first correlation metric based on a correlation of the training sequence of the signal with a local training sequence for the UE in a VAMOS mode;generating a second correlation metric based on a correlation of the training sequence of the signal with a local training sequence for the UE in a non-VAMOS mode; anddetermining the switch metric based on the first correlation metric and the second correlation metric.4. The method of claim 1 , further comprising:designing a cost function include the correlation metrics of the training sequence of the signal;estimating a hypothesis for the cost function; anddetermining the threshold based on the hypothesis.5. The method of claim 1 , wherein the ...

METHOD AND DEVICE FOR RECEIVING A SIGNAL THE PHASE OR FREQUENCY OF WHICH IS MODULATED BY A SEQUENCE OF TWO-STATE SYMBOLS

A method allowing a receiver device of a wireless communication system to receive a useful signal emitted by an emitter device. The useful signal corresponding to a signal, the phase or frequency of which is modulated by a sequence of two-state symbols corresponding to a sequence of binary data. A temporal envelope of the useful signal is detected and compared to a preset threshold value. Transitions between consecutive useful-signal symbols are detected, on the basis of the result of the comparison. A sequence of binary data is extracted from the useful signal depending on the detected transitions. 110-. (canceled)11. A method for receiving , by a receiver device of a wireless communication system , of a useful signal transmitted by a transmitter device , the useful signal corresponding to a signal that is phase-modulated or frequency-modulated by a sequence of two-state symbols corresponding to a binary data sequence , the method comprising steps of:detecting a time-domain envelope of the useful signal;comparing the detected time-domain envelope with a predetermined threshold value;detecting transitions between consecutive symbols of the useful signal, a transition between two consecutive symbols, respective states of which are different, being detected when the detected time-domain envelope is less than the predetermined threshold value, and a transition between two consecutive symbols, the respective states of which are identical, being detected when the detected time-domain envelope is greater than the predetermined threshold value; andextracting the binary data sequence from the useful signal as a function of detected transitions between different states and as a function of detected transitions between identical states.12. The reception method as claimed in claim 11 , wherein the symbols of a sequence are transmitted at a symbol period; and the reception method further comprises steps of determining decision instants separated by the symbol period; and ...

PARTIAL RESPONSE SIGNALING TECHNIQUES FOR SINGLE AND MULTI-CARRIER NONLINEAR SATELLITE SYSTEMS

New partial response signaling systems and methods for high spectral efficiency communications are described. In a first implementation, a communication system includes a partial response signaling transmitter and a nonlinear satellite transponder. The partial response signaling transmitter includes a partial response transmit filter configured to convert complex-valued data symbols to a transmit signal using a partial response pulse shaping function; and a modulator configured to modulate the transmit signal onto a carrier wave. The transponder receives and non-linearly amplifies the modulated transmit signal for broadcast to receivers. In a second implementation, a receiver includes circuitry for downconverting a received input signal; a partial response filter with a partial response impulse function for filtering the downconverted signal; circuitry for downsampling the partial response filtered signal; circuitry for equalizing the downsampled signal; and a linear and non-linear interference cancellation module including circuitry for removing linear and non-linear ISI in the input signal. 2. (canceled)3. The system of claim 1 , wherein L is 2 or 3.4. A communication system claim 1 , comprising: a first partial response transmit filter configured to convert a first set of complex-valued data symbols to a first transmit signal using a partial response pulse shaping function;', 'a second partial response transmit filter configured to convert a second set of complex-valued data symbols to a second transmit signal using a partial response pulse shaping function;', 'a modulator configured to modulate the first transmit signal onto a carrier wave for transmission as a first modulated transmit signal;', 'a modulator configured to modulate the second transmit signal onto a carrier wave for transmission as a second modulated transmit signal; and', 'an adder configured to add the first and second modulated transmit signals to generate a composite signal; and, 'a ...

DEMODULATING MODULATED SIGNALS WITH ARTIFICIAL NEURAL NETWORKS

Demodulating a modulated signal. A method may include receiving a modulated signal, wherein the modulated signal is a signal modulated according to a modulation function varying faster than the signal. The modulation function is a function of the signal. The modulated signal received is demodulated with an artificial neural network system, or ANN system, which is trained to identify bit values from signal patterns as caused by the modulation function, by identifying bit values from patterns of the modulated signal received. Related modulation and demodulation systems are disclosed. 1. (canceled)2. The method according to claim 14 , wherein the method further comprises claim 14 , prior to receiving the modulated signal:modulating the signal according to said modulation function to obtain said modulated signal; andtransmitting the modulated signal obtained, for it to be received and subsequently demodulated by the ANN system.3. The method according to claim 2 , wherein claim 2 ,the signal is a digital signal; andat modulating, the signal is modulated over each time period corresponding to each of the discrete values captured by the digital signal, respectively, to obtain the modulated signal.4. The method according to claim 3 , wherein modulating the digital signal comprises:for each of said discrete values, modulating said digital signal according to said modulation function based on two or more discrete values of the digital signal, the discrete values including said each of the discrete values, as well as one or more previous discrete values of the digital signal.5. The method according to claim 3 , whereinmodulating the digital signal comprises streaming the digital signal to a modulator, for it to modulate the signal streamed on the fly, andtransmitting comprises streaming the modulated signal to the ANN system for it to demodulate the streamed signal it receives on the fly.6. The method according to claim 14 , whereinthe method further comprises converting the ...

SYNCHRONOUSLY-SWITCHED MULTI-INPUT DEMODULATING COMPARATOR

Methods and systems are described for obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus, applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors, recovering a demodulation signal from the carrier-modulated symbols, and generating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal. 1. A method comprising:obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus;applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors;recovering a demodulation signal from the carrier-modulated symbols; andgenerating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal.2. The method of claim 1 , wherein controlling the conductivity of the set of transistors comprises selectably enabling a current source according to the demodulation signal.3. The method of claim 2 , wherein the demodulated sub-channel data output is a return-to-zero (RTZ) signal.4. The method of claim 1 , ...

APPARATUS AND METHOD FOR GENERATING DIFFERENTIAL SIGNAL, AND TRANSMISSION APPARATUS AND METHOD HAVING THE SAME

Disclosed is a technique for a transmission apparatus. A method of generating a differential signal includes adding a predetermined offset to an envelope signal to generate a first signal having the same magnitude as the envelope signal with respect to 0, scaling the first signal at a predetermined rate to generate a second signal, changing a sign of the second signal to generate a third signal that is an inverted signal of the second signal, and forming a differential signal using the second signal and the third signal. 1. A method of generating a differential signal , the method comprising:adding a predetermined offset to an envelope signal to generate a first signal having the same magnitude as the envelope signal with respect to 0;scaling the first signal at a predetermined rate to generate a second signal;changing a sign of the second signal to generate a third signal that is an inverted signal of the second signal; andforming a differential signal using the second signal and the third signal.2. The method of claim 1 , further comprising claim 1 , after the forming of the differential signal claim 1 , adding a common mode voltage to the differential signal to generate a differential signal with the common mode voltage added.3. The method of claim 1 , wherein the envelope signal is a single-ended signal.4. A transmission apparatus comprising:a polar coordinate conversion unit configured to separate an input signal into a phase signal and an envelope signal to provide the phase signal and the envelope signal;a phase modulator configured to phase-modulate the phase signal to generate a phase-modulated signal having a constant amplitude;a differential signal generation unit configured to add a predetermined offset to the envelope signal such that the envelope signal has the same magnitude with respect to 0 and generate a differential signal based on the envelope signal with the predetermined offset added;a modulator configured to modulate the differential signal to ...

SYSTEMS AND METHODS FOR MAXIMIZING POWER EFFICIENCY OF A DIGITAL POWER AMPLIFIER IN A POLAR TRANSMITTER

A polar transmitter including a digital power amplifier cell that includes a first circuit and an amplifier circuit. The first circuit is configured to receive a phase modulated carrier signal and to generate a PMOS control signal and an NMOS control signal such that the PMOS control signal and the NMOS control signal have different duty cycles. The amplifier circuit is configured to receive the PMOS control signal at a PMOS transistor and the NMOS control signal at an NMOS transistor. The first circuit is configured to align the PMOS control signal and the NMOS control signal with respect to one another such that a time that the NMOS transistor and the PMOS transistor of the amplifier circuit are simultaneously conducting is minimized. The amplifier circuit is configured to generate an amplified modulated carrier signal in response to the PMOS and NMOS control signals. 1. A polar transmitter , comprising: a first circuit configured to receive a phase modulated carrier signal and configured to generate a PMOS control signal and an NMOS control signal such that the PMOS control signal and the NMOS control signal have different duty cycles; and', 'an amplifier circuit having an output and comprising a PMOS transistor and an NMOS transistor, the amplifier circuit configured to receive the PMOS control signal at the PMOS transistor and the NMOS control signal at the NMOS transistor, wherein the first circuit is configured to align the PMOS control signal and the NMOS control signal with respect to one another such that a time that the NMOS transistor and the PMOS transistor of the amplifier circuit are simultaneously conducting is minimized,', 'wherein the amplifier circuit is further configured to generate an amplified modulated carrier signal at the output of the amplifier circuit in response to the PMOS and NMOS control signals from the first circuit., 'a digital power amplifier (DPA) cell, comprising2. The polar transmitter of claim 1 , wherein the amplified ...

DATA PROCESSING METHOD AND DEVICE

Provided are a data processing method and device. The method may include: generating first data, wherein generating the first data comprises one of: performing differential encoding on second data to generate third data, and processing the third data by using a sequence to generate the first data; processing the second data by using a sequence to generate fourth data, and performing differential encoding on the fourth data to generate the first data; and processing the second data by using a sequence to generate the first data. 1. A data processing method , comprising:generating first data, wherein generating the first data comprises one of:performing differential encoding on second data to generate third data, and performing spreading or modulation processing on the third data by using a sequence to generate the first data;performing spreading or modulation processing on the second data by using a sequence to generate fourth data, and performing differential encoding on the fourth data to generate the first data; andperforming spreading or modulation processing on the second data by using a sequence to generate the first data.21. The method as claimed in , wherein the second data comprises at least one of: a reference signal; and data information.32. The method as claimed in , wherein the reference signal comprises one of: a reference signal determined according to user identity information; a reference signal determined from a reference signal set; and a preset reference signal.42. The method as claimed in , wherein the data information comprises one of: a data bit; and a data symbol generated by performing encoding and modulation on a data bit.54. The method as claimed in , wherein the data bit comprises at least one of: payload information; user identity information; sequence information; sequence set information; and reference signal information.61. The method as claimed in , wherein the sequence comprises at least one of:a sequence randomly selected from a ...

SYNCHRONOUSLY-SWITCHED MULTI-INPUT DEMODULATING COMPARATOR

Methods and systems are described for obtaining a set of carrier-modulated symbols of a carrier-modulated codeword, each carrier-modulated symbol received via a respective wire of a plurality of wires of a multi-wire bus, applying each carrier-modulated symbol of the set of carrier-modulated symbols to a corresponding transistor of a set of transistors, the set of transistors further connected to a pair of output nodes according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors, recovering a demodulation signal from the carrier-modulated symbols, and generating a demodulated sub-channel data output as a differential voltage on the pair of output nodes based on a linear combination of the set of carrier-modulated symbols by controlling conductivity of the set of transistors according to the demodulation signal. 1. A method comprising:initializing a pair of output nodes by setting a predetermined amount of charge on the pair of output nodes according to a sampling clock;receiving a set of carrier-modulated symbols of a carrier-modulated codeword, the set of carrier-modulated symbols received as a plurality of wire signals on a multi-wire bus;applying each wire signal to a corresponding transistor of a set of transistors, the set of transistors connected to the pair of output nodes and the multi-wire bus according to a sub-channel vector of a plurality of mutually orthogonal sub-channel vectors;generating a demodulation signal having a frequency associated with the set of carrier-modulated symbols; andgenerating a demodulated sub-channel data output as a differential voltage on the pair of output nodes, the differential voltage generated based on a differential current formed from a linear combination of the plurality of wire signals, the differential current generated responsive to controlling conductivity of the set of transistors according to the demodulation signal during an integration period determined by the sampling clock.2. The ...

DATA TRANSMISSION, IN PARTICULAR ON A SERIAL LINK HAVING A GREAT LENGTH

Binary data is processed through a differential pre-encoder, which includes a simple modulo-2 addition. This step is used to cancel the propagation error that can be introduced by duo-binary modulation and to simplify demodulation. Next the duo-binary encoder introduces controlled Inter Symbol Interference between a previously sent bit and a present bit to compress the spectral density closer to the DC. Next a 60-GHz carrier is modulated and transmitted over differential transmission lines. 1. A device , comprising:a transmission stage;a receiving stage; anda communication medium coupled between the transmission stage and the receiving stage; input circuitry configured to receive an input base band signal;', 'differential encoding circuitry coupled to said input circuitry and configured to perform a differential encoding of said input base band signal and to deliver an encoded signal;', 'modulation circuitry configured to perform a poly-binary modulation of said encoded signal and to deliver a modulated signal; and', 'transposition circuitry configured to perform an upward frequency transposition of said modulated signal to a radiofrequency domain;', 'wherein said communication medium has a first end coupled to an output of said transposition circuitry and a second end configured to deliver a transmitted signal; and, 'wherein said transmission stage comprises demodulation circuitry coupled to said second end and configured to perform a downward frequency transposition of a signal issued from the transmitted signal and to deliver a received base band signal;', 'detection circuitry coupled between an output of said demodulation circuitry and output circuitry and configured to perform a decision process on a signal issued from said received base band signal; and', 'wherein said output circuitry is configured to deliver an output base band signal issued from the decision process., 'wherein said receiving stage comprises2. The device according to claim 1 , wherein said ...

Method and a device for decoding differentially modulated symbols

确定应用于接收信号的调制方法的方法和接收器

本发明涉及确定应用于接收信号的调制方法的方法，所述方法包括使用至少两个不同调制方法解调所述接收信号；针对每个解调信号确定所述信道的估测，所述信道的所述估测包括第一数目m个抽头；选择每个信道估测的所述抽头中的第二数目n个，第二数目n小于第一数目m；根据所述第二数目n个抽头估测每个解调信号的方差；和比较估测方差并且根据所述比较确定应用于接收信号的调制方法。

Pulse shaping for the control of the amplitude variation of PSK signals

Digital transmitter with constrained envelope and spectral regrowth over a plurality of carriers

A constrained-envelope digital communications transmitter ( 10 ) places constraints on the envelope of spectrally constrained, digitally modulated communication signals ( 46 ) converted into diverse frequency channels ( 54 ) and combined into a composite signal ( 58 ). The envelope constraints achieve lower peak-to-average power ratio without allowing significant spectral regrowth. The composite signal ( 58 ) is applied to a plurality of cascade-coupled constrained-envelope generators ( 64 ). Each constrained-envelope generator ( 64 ) detects overpeak events ( 66 ) and configures corrective impulses ( 68 ) for the overpeak events ( 66 ). The corrective impulses ( 68 ) are distributed to the respective frequency channels ( 54 ) in accordance with a predetermined distribution profile ( 102 ) and are filtered into allocated shaped pulses ( 120 ) that exhibit a constrained spectrum. The allocated shaped pulses ( 120 ) are coherently converted into the respective frequency channels ( 54 ) and combined with the composite signal ( 58 ) to reduce an unwanted signal peak.

Transmitter and integrated circuit comprising the same

송신기(10)는 위상 변조기(12)와 상대적으로 고출력인 전압 제어 발진기(VCO)(16)를 구비하는 위상 동기 루프(PLL)(14)를 포함한다. PLL(14)은 VCO 출력으로부터 유도된 위상 비교 주파수를 위상 변조기로부터 유도된 위상 변조된 IF 반송파와 비교하기 위한 위상 감지 검출기(30)를 포함한다. 위상 변조기(12)는 기준 주파수 소스(42), 상기 소스에 의해 생성된 기준 주파수의 4개의 직교 위상 성분을 유도하기 위한 수단(44) 및 상기 4 개의 직교 성분들 사이에 랜덤 보간법을 통해 위상 변조된 IF 반송파를 유도하기 위하여 복소 변조 수단(50, 52)에 의해 제어되는 위상 선택 수단(46)을 포함한다. Transmitter 10 includes a phase locked loop (PLL) 14 having a phase modulator 12 and a relatively high power voltage controlled oscillator (VCO) 16. PLL 14 includes a phase sensing detector 30 for comparing the phase comparison frequency derived from the VCO output with the phase modulated IF carrier derived from the phase modulator. Phase modulator 12 provides a phase modulation via a random interpolation between a reference frequency source 42, means 44 for deriving four quadrature phase components of the reference frequency generated by the source and the four quadrature components. Phase selection means 46 controlled by complex modulation means 50 and 52 to derive the IF carriers.

Carrier on/off system

(57)【要約】本公報は電子出願前の出願データであるた め要約のデータは記録されません。

Multi-phase psk modulation circuit

(57)【要約】本公報は電子出願前の出願データであるた め要約のデータは記録されません。

Method for generating I/Q signal in a TDMA transmitter and corresponding modulator

The present invention relates to a digital I/Q modulator which efficiently supports multi-time-slot operation of wireless TDMA transmitters employing linear power amplifiers. According to the present invention, dips are introduced in the envelope of the I/Q signal in the guard interval between adjacent time-slots or bursts. The dips avoid interference on adjacent radio frequency channels when the gain of the TX chain in switched abruptly in order to change the power level of the TX signal or when the modulation scheme is changed. Also, a method is provided for generating the dips, which is particularly attractive if the modulation scheme in adjacent time-slots changes from GMSK to 8PSK or vice versa.

Signal receiving method and receiving apparatus

The method involves generating a receiving signal (604) having pseudo-random codes from an analog signal sampled with multiple bits. The receiving signal is modulated in a complex and phase continuous manner, and generating a pseudo-random code sequence. The receiving signal is filtered with a Laurent decomposition filter (618), such that a receiver-generated signal is generated. The receiving signal is correlated with the receiver-generated signal having pseudo-random codes. The receiver-generated signal is quantized with multiple bits. An independent claim is also included for a receiver for receiving a phase continuous signal.

Transmitter

송신중에 어느 순간에 포락이 제로로 감소하는 변조시스템을 사용하는 송신장치는 신호포인트 배열에 송신신호를 맵핑하기 위한 맵핑회로, 맵핑회로에 의해 획득된 I와 Q채널에 대한 신호를 각각 아날로그 신호로 변환시키기 위한 D/A컴버터, 송신 온/오프 제어신호에 따라 변환된 아날로그 신호를 각각 턴온 및 오프 시키기 위한 스위치, 및 온 및 오프 제어된 아날로그 신호를 대역-제한하기 위한 대역 제한 필터를 포함한다. 포락의 변화는 송신의 개시직후와 비교하면 송신중에 증가하여 따라서 송신동안 필터로 인접채널간의 누설전력을 억제함으로써 램프 프로세서가 송신신호의 온 및 오프제어에 따라 스위치에 의해 수행될 수 있다.

Digital radio communication system utilizing quadrature modulated carrier waves

"Digital Radio Communication System Utilizing Quadrature Modulated Carrier Waves" ABSTRACT In order to achieve the spectrum economy and reduce the power consumption of a transmitter and reduce the error rate at a receiver and simplify receiver circuitry, at least one bit stream to be transmitted is quadrature modulated in a manner that the signal points do not define a trace on a complex amplitude plane which passes through the origin of the plane coordinates or in the vicinity thereof. The received signal is hard limited and frequency-discriminated to determine the instantaneous angular velocity of the received signal and is integrated to detect the phase variation between two consecutive received signals, and thereafter is decided with respect to the phase variation according to the decision threshold levels O and + .pi. radians.

TRANSMITTER FOR ANGULAR-MODULATING SIGNALS

EMETTEUR POUR SIGNAUX A MODULATION ANGULAIRE COMPORTANT UNE ENTREE 1 POUR DES SIGNAUX BINAIRES, UN FILTRE DE PREMODULATION 2 ET UN DISPOSITIF DE MODULATION DE FREQUENCE 3. POUR AMELIORER LE TAUX D'ERREURS DU SYSTEME D'EMETTEUR ET DE RECEPTEUR, ON UTILISE UN FILTRE DE PREMODULATION PRESENTANT UNE REPONSE TRANSMITTER FOR ANGULAR MODULATION SIGNALS INCLUDING AN INPUT 1 FOR BINARY SIGNALS, A PREMODULATION FILTER 2 AND A FREQUENCY MODULATION DEVICE 3. TO IMPROVE THE ERROR RATE OF THE TRANSMITTER AND RECEIVER SYSTEM, A DRIVE FILTER IS USED. PREMODULATION PRESENTING A RESPONSE

DIGITAL MODULATION METHOD, AND MODULATOR USING SUCH A METHOD

On convertit les symboles successifs (ai ) d'un train de signal numérique en incréments de phase (DELTAphi) qui sont accumulés. On obtient une phase modulante (PSI) par filtrage de la phase accumulée. On produit un signal complexe dont l'argument représente la phase modulante. On module respectivement deux ondes radio en quadrature de phase sur la base de ce signal complexe, et on émet un signal radio résultant d'une combinaison des deux ondes modulées. Le signal complexe est à son tour filtré numériquement. Ses parties réelle et imaginaire (I, Q, converties en analogique, sont soumises à un filtrage analogique anti-repliement puis mélangées aux deux ondes radio. Un dimensionnement approprié des filtres numériques permet d'obtenir une modulation efficace présentant de faibles variations d'enveloppe et produisant peu d'interférences entre canaux fréquentiels adjacents, avec un faible taux d'erreur. The successive symbols (ai ) of a digital signal train are converted into phase increments (DELTAphi) which are accumulated. A modulating phase (PSI) is obtained by filtering the accumulated phase. A complex signal is produced whose argument represents the modulating phase. Two radio waves are respectively modulated in phase quadrature on the basis of this complex signal, and a radio signal resulting from a combination of the two modulated waves is transmitted. The complex signal is in turn digitally filtered. Its real and imaginary parts (I, Q, converted to analog, are subjected to analog anti-aliasing filtering and then mixed with the two radio waves. Appropriate sizing of the digital filters makes it possible to obtain effective modulation with low envelope variations and producing little interference between adjacent frequency channels, with a low error rate.

8-phase psk modulator

D- 21,283 by Stevan D. Bradley ABSTRACT OF DISCLOSURE This 8-phase modulator comprises logic circuitry for converting tribits XYZ of input data into binary control signals D1, D2, D3 and D4 according to a prescribed plan, a pair of 4-phase signal generators responsive to associated pairs of control signals, and a signal source producing a pair of equal amplitude carrier signals of the same frequency and of phases which differ by 45° for driving associated ones of the 4-phase generators 45° out-of-phase. Equal amplitude vector signals from the two 4-phase generators are combined to produce a resultant vector signal which individually generates the phasors of an 8-phase signal set.

ESTIMATOR OF THE BALANCE DEFECT OF A QUADRATURE MODULATOR AND MODULATION STAGE USING THE SAME

PHASE MODULATOR

DIGITAL MODULATION METHOD, AND MODULATOR IMPLEMENTING SUCH A METHOD

Patent FR2503498B1

Modulation of a digital signal to produce a narrow band output with approximately constant envelope

The transmitted signal results from the modulation of digital data by a modulation function which is a Gaussian function of time t. The digital data comprises a set of bits bk identified by rank k and of duration T. The transmitted signal consists of an indexed sum by rank k of the product of the complex constant j to the power k, of the modulation function h(t-kT) and of the input data. The modulator comprises a signal processor (PR) which splits the input signal into real and imaginary components in the form S = I + jQ. A time base (BDT) generates a clock Ck and a carrier C. The carrier is fed into a de-phaser circuit DEP. Mixer M1 combines the carrier with real signal I and mixer M2 combines the de-phased carrier with the complex component of the signal. The two outputs are then summed.

METHOD AND DEVICE FOR DIGITAL MODULATION WITH PHASE AND QUADRATURE COMPONENTS.

Patent FR2729261B1

DATA SIGNAL TRANSMISSION SYSTEM USING A CARRIER WAVE WITH ANGULAR MODULATION AND CONSTANT AMPLITUDE

Système comprenant un émetteur et un récepteur pour la transmission de signaux de donnée binaires à une frequence symbole donnée, l'étage de modulation de l'émetteur produisant un signal d'onde porteuse à modulation angulaire ayant une amplitude pratiquement constante et une phase continue et le signal modulé transmis étant démodulé dans le récepteur de façon orthogonale et cohérente. L'étage de modulation est agencé de façon que la phase du signal modulé, au cours de chaque intervalle symbole, varie d'une quantité comprise dans la série - pi /2, - pi /4, 0, pi /4, pi /2 (radian), cette quantité, pour l'intervalle symbole considéré, étant déterminée par au moins deux symboles de données successifs, la forme de la phase à l'intérieur de cet intervalle symbole étant déterminée par une version filtrée d'au moins ces deux symboles de données successifs. Application : transmission de données par liaisons radioélectriques. A system comprising a transmitter and a receiver for the transmission of binary data signals at a given symbol frequency, the modulation stage of the transmitter producing an angularly modulated carrier wave signal having a substantially constant amplitude and a continuous phase and the transmitted modulated signal being demodulated in the receiver in an orthogonal and coherent fashion. The modulation stage is arranged so that the phase of the modulated signal, during each symbol interval, varies by a quantity included in the series - pi / 2, - pi / 4, 0, pi / 4, pi / 2 (radian), this quantity, for the symbol interval considered, being determined by at least two successive data symbols, the shape of the phase within this symbol interval being determined by a filtered version of at least these two successive data symbols. Application: data transmission by radio links.

METHOD FOR REDUCING THE ENERGY OF SIDE LOBES OF A MINIMUM MODULATION DETECTABLE SIGNAL

L'INVENTION VISE UN PROCEDE ET UN DISPOSITIF POUR LA GENERATION D'UN SIGNAL DETECTABLE EN MODULATION A MINIMUM PRESENTANT UNE ENERGIE DE LOBES LATERAUX REDUITE DU TYPE DANS LEQUEL LE SIGNAL DETECTABLE EN MODULATION A MINIMUM COMPORTE DEUX CANAUX ORTHOGONAUX COMBINES DESTINES A VEHICULER UN SIGNAL DE DONNEES. UNE CONFIGURATION DE PROFIL D'ENVELOPPE DE MODULATION DE CANAL PREDETERMINEE EST SELECTIONNEE EN FONCTION D'UN GROUPE DE BITS DE DONNEES ET LES CANAUX ORTHOGONAUX RESPECTIFS SONT MODULES EN AMPLITUDE DANS LES MODULATEURS 62, 63 SELECTIONNES. LA SOMMATION DES CANAUX ORTHOGONAUX DANS LE SOMMATEUR 65 CONDUIT A UN SIGNAL D'AMPLITUDE CONSTANTE DONT LES LOBES D'ORDRE SUPERIEUR ONT UNE ENERGIE FORTEMENT REDUITE. L'INVENTION S'APPLIQUE NOTAMMENT AUX TELECOMMUNICATIONS A TRES BASSE FREQUENCE. THE INVENTION AIMS AT A PROCESS AND A DEVICE FOR THE GENERATION OF A DETECTABLE SIGNAL IN MINIMUM MODULATION PRESENTING A REDUCED SIDE LOBE ENERGY OF THE TYPE IN WHICH THE DETECTABLE SIGNAL IN MINIMUM MODULATION COMBINES TWO ORTHOGONAL CHANNELS COMBINED FOR A VEHICULER SIGNAL DATA. A PREDETERMINED CHANNEL MODULATION ENVELOPE PROFILE CONFIGURATION IS SELECTED BASED ON A GROUP OF DATA BITS AND THE RESPECTIVE ORTHOGONAL CHANNELS ARE MODULATED IN AMPLITUDE IN MODULATORS 62, 63 SELECTED. THE SUMMATION OF THE ORTHOGONAL CHANNELS IN THE SUMMER 65 LEADS TO A CONSTANT AMPLITUDE SIGNAL OF WHICH THE HIGHER ORDER LOBES HAVE HIGHLY REDUCED ENERGY. THE INVENTION APPLIES IN PARTICULAR TO VERY LOW FREQUENCY TELECOMMUNICATIONS.

METHOD AND DEVICE FOR DIGITAL MODULATION COMPRISING PHASE AND QUADRATURE COMPONENTS.

Le dispositif, utilisable notamment pour la radiotéléphonie entre mobiles, comprend un générateur GMSK dont les sorties en phase et en quadrature attaquent chacune une voie comprenant un générateur SIGMADELTA (28) et un modulateur (30) qui reçoit la porteuse à fréquence moitié de la fréquence des bits de sortie du convertisseur SIGMADELTA, les deux voies, dont les porteuses sont en quadrature, attaquant un mélangeur (32). The device, which can be used in particular for radiotelephony between mobiles, comprises a GMSK generator whose in-phase and quadrature outputs each drive a channel comprising a SIGMADELTA generator (28) and a modulator (30) which receives the carrier at half the frequency. output bits from the SIGMADELTA converter, the two channels, whose carriers are in quadrature, driving a mixer (32).

Patent FR2149552A1

SYSTEM FOR TRANSMITTING DATA SIGNALS USING AN ANGULAR MODULATING CARRIER AND CONSTANT AMPLITUDE

Differential phase shift keying method and device therefor

(57)【要約】 【課題】 サイン・コサイン関数、乗加減算の複雑な計 算を行わずにすみ、簡素で処理時間の速いπ／ｎシフト ｎ差分位相シフトキーイング（ＤＰＳＫ）方式の変調装 置を提供する。 【解決手段】 変換器２１０で直列データ列ｂｍを並列 変換したそのデータによる位相変化量インデックス及び 前の出力位相インデックスの関係を示したテーブルに従 い現在の出力位相インデックスを決定し、そして、その 現在の出力位相インデックスを前の出力位相インデック スとして使用するために保持する出力位相インデックス 決定器２２０と、現在の出力位相インデックスに従い出 力値決定テーブルから直角位相成分値Ｑｋと同相成分値 Ｉｋを決定する出力値決定器２３０と、を備える。即 ち、直前の出力位相と位相変化量との関係を示したテー ブルを用い、入力データにより位相変化量が指定される ごとにそのテーブルに従って現在の出力位相を決定す る。

MODULATOR, PARTICULARLY FOR CELLULAR DIGITAL TELEPHONE SYSTEMS.

˜/4 shift qpsk modulator

Abstract A .pi./4 shift QPSK modulator has a phase operator for receiving first and second input data at a predetermined symbol cycle, and for producing a first pair of output data after every even number symbol cycle and producing a second pair of output data after every odd number symbol cycle. The first and second pairs of output data are applied to four digital filters. A selector sequentially selects and produces the four filtered digital data. An invertor inverts the polarity of the filtered digital data after every four filtered digital data from the selector.

CIRCUIT FOR RECOVERY OF CARRIER SIGNALS.

Quadrature modulation circuit

Filtering for transmission using quadrature modulation

Wireless communication apparatus

Dual purpose modulator

The present invention provides a single modulator capable of transmitting an input according to a first and a second modulation technique. The first modulation technique represents changes in the input using a first set of carrier waveform parameters, such as phase variations, whereas the second modulation technique represents changes in the input using a second set of carrier waveform parameters, such as alternative phase variations. The present invention performs both modulation techniques by expressing the 10 second set of carrier waveform parameters as a subset of the first set of carrier waveform parameters. In a preferred embodiment, the first and second modulation techniques comprise the π/2-offset 2PSK (a good approximation of differential GMSK) and 3π/8-offset 8PSK (also known as EDGE) modulation techniques.

CARRIER AND PACE FREQUENCY RECOVERY FOR DIGITAL TRANSMISSION SYSTEMS WITH PHASE OR AMPLITUDE STATE MODULATION AND CONSISTENT DEMODULATION

Digital receiver and method for processing received signals

A digital receiver for a burst-mode wireless communication system, such as a Bluetooth system comprises a radio frequency input stage for receiving an input signal and an analogue-to-digital converter for converting the input signal from an analogue signal to a digital signal. A switch is coupled to the analogue-to-digital converter and a first signal processor is coupled to the switch and is arranged to demodulate signals modulated according to a first modulation process, such as a GFSK modulation process. A second signal processor is also coupled to the switch and is arranged to demodulate signals modulated according to a second modulation process, such as π/4DQPSK modulation process or an 8DPSK modulation process. The switch is arranged to switch the digital signal between the first and second signal processors to recover signals from the first and/or the second modulation process. A method for processing received signals in a burst-mode wireless communication system is also disclosed.

Digital signal transmission method and transmitter for transmission

심볼 표시 비트가 인코드되고 변조 계획을 나타내는 배치점의 각각의 점에 할당되어 있는 디지틀 변조기 각각의 배치점을 나타내는 벡터의 구직 성분은 진리표 (14)에 포함되어 있으며 진리표에는 컬럼과 로우가 있는데, 컬럼은 각각의 배치점을 포함하피 로우는 상대적인 동상과 구적 성분값을 포함한다. 배치점에 대해 심볼의 할당에 응답하여 진리표에 있는 적절한 럴럼이 2진 워드에 따라 병괼로 판독되고 워드 비트는 다수의 이동 레지스터(SR1내지 SR8)의 각각의 극1스떼이지 (510)에 인가되며 상기 이동 레지스터는 이전의 (N-1) 심볼에 있어서 각각의 성분값의 과정을 기억한다. 각 이동 레지스터의 각각의 스테이지(S1 내지 S10)의 출력은 N비트의 모든 조합에 대한 필터 응답 시퀀스를 기억하는 룩-입표 (16)에 어드레스로서 인가되어 각각의 이동 떼지스떠 (SRI 내지 SR8)의 스테이지에 현재 저장된 특정한 비트 조합을 나타내는 가중치된 필터 응답 시퀀스를 얻는다. 동상과 구직 위상 가중치 필터 응답 시퀀스는 조합되어 각각의 주파수 상승 변환 스테이지(18,20)에 인가되는 아날로그 신호로 변환된다.

Modulation scheme with low envelope variation for mobile radio by constraining a maximum modulus of a differential phase angle

A digital radio communication system achieves low envelope variations in a transmitted signal by encoding digital information as phase angle differences in a transmitted radio signal and by constraining the maximum possible phase angle difference. This reduction in envelope variation relaxes the linearity requirements for a desired level of distortion suppression of a radio frequency (RF) amplifier means employed for transmitting the radio signal. In addition, lower envelope variations imply a higher average transmit power for a given maximum transmitted power, thereby extending range and battery life.

Transmission of well-logging data over bandpass channels using quadrature amplitude modulation

A method and apparatus for transmitting and receiving acquired digital data over bandpass channels (i.e. channels having a limited range of frequencies) at high data transmission rates. Combined amplitude and phase modulation (quadrature ampli-tude modulation) is applied to the digital data and the sampled digital waveform converted to an analog waveform for passage over the bandpass channel. The sample rate is chosen as an integer multiple of the symbol rate and carrier frequency to signifi-cantly reduce processing overhead. Reception of the acquired data is similar to transmission and involves an analogous ampli-tude and phase demodulation. The quadrature amplitude modulation technique of the present invention is applied to an oil well-logging application to transmit the data acquired from the downhole logging instruments over the logging cable (bandpass channel) at high transmission rates.

Joint space-time optimum filters (jstof) for interference cancellation

A filter for reducing co-channel interference within a communications receiver may include a multi-channel, space-time filter circuit that filters n signal parts that have been split from a communications signal by jointly estimating space-time filter weights and multi-channel impulse responses (CIRs). The filter may further include a multi-channel, matched filter circuit that receives multi-channel signals from the multi-channel, space-time filter circuit and has a filter response that is provided by a channel impulse response estimation from the space-time filter circuit.

Apparatus, method and computer program

An apparatus, method and computer program, the apparatus including: a modulator including a first input for receiving a data signal and a second input for receiving an output signal from a phase locked loop wherein the modulator is for modulating the output signal from the phase locked loop using the data signal and providing the modulated signal to an output for connection to an amplifier; and a phase shifter configured to result in a predetermined phase shift to the modulated signal.

Method of, and transmitter for, transmitting a digital signal

A digital modulator in which symbols representing bits are encoded and assigned to respective points of constellation of points representing the modulation scheme. The quadrature components of a vector representing each of the constellation points are contained in a truth table (14) in which the columns comprise the respective constellation points and the rows comprise the relative in-phase and quadrature component values. In response to the assignment of a symbol to a constellation point the appropriate column in the truth table is read out in parallel as a binary word and the bits of the word are applied to respective first stages (S10) of a plurality of shift registers (SR1 to SR8) which store the histories of the respective component values for the previous (N-1) symbols. Outputs of each of the stages (S1 to S10) of each shift register are applied as an address to a look-up table (16) storing the filter response sequences to all combinations of N bits to obtain weighted filter response sequences representative of the particular combination of bits currently stored in the stages (S1 to S 10) of each shift register (SR1 to SR8). The in-phase and quadrature phase weighted filter response sequences are combined and converted to analogue signals which are applied to a respective frequency up-conversion stage (18,20).

Multi-carrrier optical communication method and system based on DAPSK

The present invention provides an optical communication method, comprising: performing modulation on the obtained bit stream data to generate modulated signals; performing differential encoding on the modulated signals to generate differentially encoded signals; converting the differentially encoded signals into electrical signals; and mapping the electrical signals onto optical carriers to generate optical signals for transmission. With the present invention, it is possible to enhance the system's capability of resisting inter-carrier interference without decreasing spectrum efficiency, hence improving the tolerance of existing optical communication systems towards laser linewidth, fast-changing PMD, optical fiber nonlinearity, inter-channel interference and other damages, greatly enhancing system performances.

Fractional-N digital modulation with analog IQ interface

Digital I and Q (NRZ) data streams are generated by specially configured conversion circuits, the outputs of which are applied to a F-N synthesizer to modulate the synthesizer. All illustrative conversion circuit employs a system of comparators to detect the state of analog I and Q signals at each bit interval and to decode outputs of such comparators to determine the NRZ sequence that gave rise to detected states. Once so determined, these NRZ signals are applied to an F-N synthesizer in the same manner as NRZ signals. Advantageously, inputs to present inventive embodiments may be received either as analog or digital I and Q inputs, subject to selection between input modes using only a single binary input.

Digital GMSK filter

A digital GMSK filter for use for frequency modulation of a carrier signal in a GMSK transmission system is described. The GMSK filter uses a large number of individual current sources, whose current values are individually weighted. The current sources are driven via a control logic module using a shift register with a thermometer code, such that this results in a total current with a Gaussian characteristic, which is converted across a resistor to a voltage and drives a voltage controlled oscillator (VCO). The filter provides exact implementation of the sample values, virtually without any quantization error, and requires only a small chip area for its implementation.

Phase modulation equipment

1370396 Digital transmission; phase modulation SOC LANNIONNAISE D'ELECTRONIQUE 27 April 1972 [30 April 1971 15 March 1972] 19698/72 Heading H4P In a phase modulator receiving separate bit streams A, B from which signals α<SP>1</SP>, #<SP>1</SP> and α, # (defined in the Specification) are produced, the relative delay between incident and output signals is mT where m is an integer # 2 and T is the bit period. The arrangement is stated to allow an increase in bit rate by the multiple m. In an embodiment described m = 2 which renders the transmission system transparent to clock signals. In this case information is embodied in the phase shift between successive odd numbered bits and between successive even numbered bits, clock signals being recovered by applying alternately positive and negative phase shifts to successive bits which positive and negative shifts mutually cancel. Transcoder 10 receives separate bit streams A, B and provides logic signals α<SP>1</SP>, #<SP>1</SP> and α, # with relative delay mT. An oscillator 30 through splitter 31 provides one output to inversion or ring modulator 33, also receiving half modulation frequency F<SP>1</SP>, connected through attenuator 34 to adder 35 also receiving through delay line 32, which may be of coaxial type, an output from 31. To give a determined phase shift which is dependent on the amplitude ratio between inputs to 35, attentuator 34 is adjustable. Adder output passes to a further splitter 36 giving delayed and direct inputs to inverse modulators 39, 41 also receiving inputs α, # through amplifiers 38, 40 from transcoder 10 described in greater detail with respect to Fig. 1 (not shown); adder 42 receiving outputs from 39, 41 gives a phase modulated output 43. At the receiver distributer (50) Fig. 3 (not shown) divides input signals between outputs (a-c<SP>1</SP>) which are passed respectively to delays (53, 55) also to phase comparators ( ...

Wireless communication apparatus

Disclosed is a radio communication device which when transmitting both a first information sequence, on which π/4-shift differential phase shift modulation is performed, as a delayed wave and a second information sequence, on which a differential phase shift modulation is performed, as an advance wave by using a PADM method, interchanges signal points respectively belonging to quadrants which are one of a first quadrant and a third quadrant, a second quadrant and a fourth quadrant, the first quadrant and the second quadrant, the first quadrant and the fourth quadrant, the second quadrant and the third quadrant, and the third quadrant and the fourth quadrant, the signal points being included in signal points mapped onto a complex plane which consists of a real number axis and an imaginary number axis, to change the arrangement of the information sequence.

DEVICE FOR GENERATING AN ANGLE MODULATED CARRIER SIGNAL OF CONSTANT AMPLITUDE RESPONSE TO DATA SIGNALS.

Digital modulator

Unified modulator for continuous phase modulation and phase-shift keying

A “unified” modulator for multiple modulation schemes (e.g., GMSK and 8PSK) is described. The waveform for each modulation scheme is generated based on a set of one or more pulse shaping functions. The waveforms for all supported modulation schemes may be generated based on a composite set of all the different pulse shaping functions. The unified modulator includes a filter for each pulse shaping function in the composite set. To generate the waveform for a selected modulation scheme, the set of one or more filters for this modulation scheme is enabled and all other filters are disabled. The outputs from all enabled filters are summed to generate a modulator output. When switching between modulation schemes, a smooth transition may be obtained by (1) providing a suitable data pattern for each filter to be enabled or disabled and (2) generating symbols for the new modulation scheme with an appropriate initial phase.

Quadrature signal generation circuit

ABSTRACT OF THE DISCLOSURE : Quadrature signal generation circuit A quadrature signal generation circuit (QGM) is proposed that allows to directly control the phase shift between an in-phase (IS) and quadrature-phase (QS) carrier signal derived from a master carrier signal (CS) having a desired carrier frequency. The circuit (QGM) derives first and second signals which are roughly orthogonal through an untuned RC- and CR-filter respectively (IRC, RCQ) and then derives the mentioned carrier signals (IS, QS) by cross-wise adding to these first and second amplified signals, the output signals of the above filters. The orthogonality of the above carrier signals may then be controlled via a phase adjust signal (PAS) which modifies the sign and the amplitude with which the above mentioned output signals are added to the amplified signals.

Digital pre-modulation filter

A digital pre-modulation filter with a finite impulse response having the value k(t)=h(t)·w(t), where h(t) represents an impulse response of the type that is customary for a modulator, for generating in response to data signals an angle-modulated carrier signal having a substantially constant amplitude, and w(t) represents a window function by which the impulse response of the pre-modulation filter is truncated softly. It turns out to be possible to reduce the disturbing effects with respect to the power spectrum caused by such a soft truncation and cancel them with respect to the phase of the angle-modulated carrier signal. Thereto, according to the invention the impulse response k(t)=A{g(t)+x(t)}·w(t) is selected where A is a correction factor which is usually equal to one, g(t) is the untruncated impulse response of the filter, x(t) is a constant c c or a time-dependent correction function which in a preferred embodiment has such a variation that for example ##EQU1## for any integer value of i.

Synchronisation and detection of modulation type

In a communication system, including a transmitter and a receiver, the receiver is synchronized with the transmitter, and a modulation type in a signal transmitted by the transmitter and received by the receiver is detected. A first portion of the received signal is correlated with one or more signals, representing modulation types used by the communication system to detect the type of modulation being used. Synchronization is established between the transmitter and the receiver. The first portion may be correlated with each of one or more different signals, representing various modulation types used in the communication system to detect the type of modulation used. Alternately, the first portion of the received signal may be derotated by different amounts, to produce a plurality of derotated signals that are correlated with the signal representing modulation used by the communication system, in order to detect the type of modulation used. If the correlation does not result in a determination of the modulation type, either a predetermined modulation type is selected or the decision of modulations type is made at a later stage, based, e.g., on a comparison of signal qualities or equalization results.

Constant amplitude modulator

Method for quadrature-quadrature amplitude modulation with constant amplitude characteristic and its apparatus

현재, 이동통신이나 개인통신 또는 위성통신 등에 있어서는 그 변조방식으로서 QPSK(Quadrature Phase Shift Keying)나 MSK(Minium Shift Keying) 계열의 변조방식을 채용하고 있고, 최근에는 기존의 Q 2 PSK(Quadrature-Quadrature PSK)와 QAM(Quadrature Amplitude Modulation) 방식을 결합하여 대역폭효율을 향상시킨 Q 2 AM, 즉 쌍직교진폭변조방식에 대해 연구가 진행되고 있다. Currently, modulation schemes such as QPSK (Quadrature Phase Shift Keying) and MSK (Minium Shift Keying) are adopted as modulation methods in mobile communication, personal communication, satellite communication, and the like. Recently, existing Q 2 PSK (Quadrature-Quadrature PSK) and QAM (Quadrature Amplitude Modulation) to improve the bandwidth efficiency of Q 2 AM, that is, a pair of quadrature amplitude modulation methods. 그러나, 상기한 쌍직교진폭변조방법은 송신데이터에 따라 그 출력신호의 진폭이 변동되기 때문에 비선형 증폭기를 채용하는 상기한 무선통신 시스템에는 사용할 수 없다는 문제가 있게 된다. However, the above-described quadrature amplitude modulation method has a problem in that it can not be used in the above-mentioned wireless communication system employing a nonlinear amplifier because the amplitude of its output signal varies according to transmission data. 본 발명에 있어서는 예컨데 8비트를 2비트 단위로 레벨변환하여 변조한 후, 이를 가산하여 전송하도록 된 종래의 쌍직교진폭변조방식에 있어서, 전송비트를 4비트로 하면서 4비트의 용장비트(Parity bit)를 부가하게 된다. 그리고, 상기 용장 비트는 출력되는 변조신호의 진폭이 정진폭을 갖도록 그 데이터값이 설정된다. In the present invention, for example, in a conventional bi-quadrature amplitude modulation scheme in which 8 bits are level-converted by 2-bit units and then modulated and added, a 4-bit parity bit is generated, . The redundant bit is set such that the amplitude of the output modulated signal has a constant amplitude. 본 발명에 있어서는 상기 용장비트를 생성하는 정진폭부호기가 제공된다. 그리고, 상기 정진폭부호기는 송신할 데이터를 소정의 조합단위로 가산하는 모듈로-2 가산기를 포함하여 구성된다. In the present invention, a constant amplitude encoder for generating the redundant bits is provided. The constant amplitude coder includes a modulo-2 adder for adding data to be transmitted in a predetermined combination unit. 따라서, 본 발명은 비교적 간단한 구성으로 쌍직교진폭변조방식에 정진폭특성을 부가함으로써 비선형 시스템에 적용할 수 있는 대역폭효율이 우수한 변조방법을 제공하게 된다. ...

Systems, methods, and apparatus for reducing dynamic range requirements of a power amplifier in a wireless device

Systems, methods, and apparatus for reducing dynamic range requirements of a power amplifier in a wireless device are provided. An exemplary method may include modulating a symbol stream to generate a modulated waveform. The exemplary method may further include generating at least one pulse having a peak aligned with an anticipated position of a peak or a null corresponding to the modulated waveform, where the anticipated position of the a peak or the null corresponding to modulated waveform may be determined by detecting a transition in a phase or an amplitude of the modulated waveform.

Apparatus for reducing degradation in performance caused by coupling

Digital gaussian frequency shift keying modulator

A GFSK modulator suitable for use in an RF communication system comprising a modular subsystem and a baseband processor subsystem which is implemented digitally. The baseband processor subsystem comprises a Gaussian filter, phase accumulator and cosine and sine look up tables. The baseband processor functions to convert an input data sequence into I and Q output signals. The I and Q signals are subsequently modulated by a quadrature modulator to yield a GFSK modulated signal which can then be amplified and placed into the channel. The response of the Gaussian filter is pre-calculated for all possible combinations of the input data and the results are quantized and stored in a look up table. The quantized phase results (either magnitude or differences), generated in response to the input data, are accumulated digitally and converted to I and Q signals. The modulator may be implemented using three look up tables: two of which are for storing cosine and sine values and the third is used to store the pre-calculated quantized phase results (either absolute magnitudes or differences). The size of the three look up tables may be reduced by taking advantage of the symmetry properties of the Gaussian filter response and the cosine and sine functions.

PHASE SHIFT KEY MODULATOR

System and method for communicating data using constant amplitude equalized waveform

A system communicates data and includes an encoder for encoding communications data with a forward error correction code. A data randomizer randomizes the communications data with a random bit sequence and a combining circuit combines the communications data with known symbols into frames. A modulator maps the communications data into minimum shift keying or Gaussian minimum shift keying (MSK or GMSK) symbols based on a specific mapping algorithm to form a communications signal having an MSK or GMSK waveform over which the communications data can be transmitted.

Method and apparatus for quadriphase-shift-key and linear phase modulation

A submultiple (30Fl) of an S-band transmitter output frequency (240Fl) is divided equally between a linear phase modulation branch and a QPSK modulation branch. The linear modulation branch includes a multiplier (X7) to increase the carrier frequency to a level (210Fl) which, when combined with the carrier in the QPSK branch in an up-converter (utilizing a mixer at the input thereof followed by a bandpass filter), produces the transmitter output frequency. This allows the QPSK modulator to operate at one-eighth of the output frequency where repeatable and precisely controlled modulation can be easily achieved. This also allows linear phase modulation at one-eighth the output frequency where low modulator deviation and good linearity can be easily maintained.

Method and system for block arq with reselection of fec coding and/or modulation

A communication system supports multiple modulation/coding schemes. When connection quality drops below an acceptable threshold, ARQ techniques use an alternative modulation/coding scheme which is more resistant to noise and/or interference. Flexible resegmentation and mapping of information blocks is supported.

Nonlinear constant envelope modulator and transmission architecture

A system for interrupting a transmitter output wave

In a transmitter, a modulator (1) switchably operates on one of two modes of operations, that is, in a first mode of the operation, such as an offset QPSK, FSK or π/4shift QPSK, an amplitude of an output signal of the modulator does not become zero at any instant, and in a second mode of the operation, such as two-phase FSK or four-phase PSK, the output signal of the modulator is 100% amplitude-­modulated or 180 phase-modulated. The operation mode is switched by changing the mode of the parallel input signals to the modulator, where the parallel signals have been converted from a serial input data signal to be transmitted. After the first mode operation is switched to the second mode operation the output signal is interrupted preferably on a first moment that the amplitude of the output signal becomes zero, as well as, before the second mode operation is switched to the first mode operation the output signal is resumed preferably on a second moment that the amplitude of the output signal is to become zero. The interruption of the modulated output signal may be done by cutting theiocal frequency or modulated signal, or by the parallel input signals. Thus, spurious wave is not generated on the transition of interrupting or resuming the modulated transmittal wave, and the period of the interrupting can be short enough.

Transmit method and system for Ka band transmissions

An improved method and system for generating quadrature phase shift keying signals for use in data transmission is provided. A pair of oscillators are slaved to the transmit frequency and produce two quadrature signal components with the same frequency but 90 degrees out of phase. The two signal components are carried to separate bi-phase switches by mirrored waveguides. Each bi-phase switch has a reflective waveguide coupler which directs the received signal into a waveguide terminated by a hard short and has a controllable shorting plane spaced approximately one-quarter wavelength from the termination point. The shorting planes are controlled by the output data signals and each introduces a 180 degree phase shift in the respective signal component when activated. The reflective couplers direct the selectively phase shifted signal components to an in-phase combiner, where they are combined to produce the quadrature phase shift keyed output signal.

Converter for converting a modulating signal with variable envelope to two modulating signals without variable envelope, transmitter using the converter and method for transmitting a modulated wave with variable envelope

A base band waveform generation circuit 10 calculates the equations: I1 = {I+Q SQRT(4/a2 - 1)}/2; Q1 = {Q-I SQRT(4/a2 - 1)}/2; I2 = {I-Q SQRT(4/a2 - 1)}/2; and Q2 = {Q+I SQRT(4/a2 - 1)}/2, based on I and Q of a modulating signal. Where, SQRT(x) refers to a square root of x, that is, a2 = (I2)2 + (Q2)2. A quadrature modulator 12 quadrature modulates a carrier with the I1 and Q1. A quadrature modulator 22 quadrature modulates a carrier with the I2 and Q2. The output signals of the quadrature modulators 12 and 13 are amplified with a transmission power amplifiers 13 and 23, then composed.

Transmission and detection of the type of modulation in digital communication systems by means of a phase rotation factor imprinted on the training sequence

Für eine blinde Modulationsdetektion werden senderseitig die Datensymbole der Trainingssequenz um einen für die verwendete Modulationsart spezifischen Phasenrotationsfaktor rotiert und empfängerseitig werden die Datensymbole um verschiedene Phasenrotationsfaktoren rück- oder derotiert und zwischen den dadurch erhaltenen Sequenzen und der ursprünglichen Trainingssequenz wird eine Korrelationsfunktion gebildet. Die verwendete Modulationsart ergibt sich daraus, bei welchem Phasenrotationsfaktor sich ein Maximum der Korrelationsfunktion ergibt. For blind modulation detection, the data symbols of the training sequence are rotated on the transmitter side by a phase rotation factor specific to the type of modulation used and on the receiver side, the data symbols are reversed or derotated by various phase rotation factors and a correlation function is formed between the sequences thus obtained and the original training sequence. The type of modulation used results from the phase rotation factor at which a maximum of the correlation function results.

Angular modulation signal generator and amplitude and phase modulation signal generator relative thereto

(57)【要約】本公報は電子出願前の出願データであるた め要約のデータは記録されません。

Rf transmitter with interleaved iq modulation

광대역 신호를 지원하는 RF 변조기는 동위상 및 직교 신호를 인터리빙함으로써 IQ 변조를 포함한다. 변조기는 동위상 아날로그 입력 신호를 수신하는 기저대역 동위상 스테이지(10), 직교 아날로그 입력 신호를 수신하는 기저 대역 직교 스테이지(12), 및 복수의 스위치를 갖는 스위칭 믹서(18)를 구비하는 집적 회로를 이용하여 구현될 수 있다. 스위칭 믹서는 기저 대역 동위상 스테이지 및 기저 대역 직교 스테이지로부터 동위상 및 직교 신호를 수신한다. 스위칭 믹서는, 복수의 반송파 구간의 페이즈에 걸쳐 신호를 인터리빙하여 동위상 및 직교 신호를 결합하는 차분 신호를 생성한다. 광대역 신호, 변조기, 직교 위상 신호, 동위상 신호, 셀룰러 전화 RF modulators supporting wideband signals include IQ modulation by interleaving in-phase and quadrature signals. The modulator is an integrated circuit comprising a baseband in-phase stage 10 for receiving an in-phase analog input signal, a baseband orthogonal stage 12 for receiving an orthogonal analog input signal, and a switching mixer 18 having a plurality of switches. It can be implemented using. The switching mixer receives in-phase and quadrature signals from the baseband in-phase stage and the baseband orthogonal stage. The switching mixer interleaves the signals over phases of a plurality of carrier intervals to generate differential signals that combine in-phase and quadrature signals. Wideband signal, modulator, quadrature signal, in-phase signal, cellular phone

Process for digital transmission and direct conversion receiver

The transmitter uses a synthesized oscillator (1A) whose reference (24) is provided by the clock (H) of the data (P, Q). The demodulation oscillator (13A) of the receiver is a synthesizer which is functionally identical to that (1A) of the transmitter, and its reference (23) is provided by the clock (H, 36) recovered from the received data.

Wireless communication apparatus, communication method, and communication system

Disclosed is a radio communication device which when transmitting both a first information sequence, on which À/4-shift differential phase shift modulation is performed, as a delayed wave and a second information sequence, on which a differential phase shift modulation is performed, as an advance wave by using a PADM method, interchanges signal points respectively belonging to quadrants which are one of a first quadrant and a third quadrant, a second quadrant and a fourth quadrant, the first quadrant and the second quadrant, the first quadrant and the fourth quadrant, the second quadrant and the third quadrant, and the third quadrant and the fourth quadrant, the signal points being included in signal points mapped onto a complex plane which consists of a real number axis and an imaginary number axis, to change the arrangement of the information sequence.

A data frequency modulator with deviation control

An automatic deviation control circuit for an angle modulated data transmitter wherein the deviation level of modulated data output from VCO (300) is controlled by a modulation cancelling deviation error detection feedback loop comprising mixer (600), phase detector (408A), low pass filter (410), and VCO (406). After the modulation is cancelled by said feedback loop from a sample of modulated carrier by a predetermined value of deviation developed by divider (302), residual modulation is detected by phase detector (408A), sampled by S/H (808 and 810) following a predetermined number of like-level data bits, and applied to the modulation path gain of amplifier (802) to increase or decrease the deviation such that the residual modulation is minimized.

CLUTCH TO MAKE AN ANGLE-MODULATED BEAR SIGNAL WITH CONSTANT AMPLITUDE REPLYING TO DATA SIGNALS

Method of producing modulating waveforms with constant envelope

Table-driven modulation signal generation

Dibits (i.e., pairs of bits) in an input data stream are converted into a modulation signal (e.g., a .pi./4-DQPSK modulation signal) using a technique that relies on pre-computed filter output values to reduce the processing required to generate each sample in the modulation signal. The pre-computed filter output values are stored in one or more look-up tables, which are accessed in real time during signal conversion to retrieve values as needed. In one implementation, the dibits, which are represented by complex values in a complex symbol space, are converted into two streams of state variables: one stream for the even symbols and one stream for the odd symbols. The two streams of state variables are used to generate address pointers that are used to access the pre-computed filter output values from the look-up tables. Addition/subtraction operations are then applied to the retrieved values to generate the real and imaginary parts of the complex samples in the modulation signal. By greatly reducing the computations involved in generating each complex sample in the modulation signal, the present invention can be used to reduce the costs of implementing the modulation process and/or increase the rate at which the input data stream is over-sampled, thereby reducing distortion in the modulation signal.

Constant amplitude psk modulator

A phase modulating system for providing PSK modulation with minimum side lobe generation. Phase changes, during the phase transition period, are accomplished with a minimum of carrier amplitude variation. I and Q components of the carrier system are multiplied (39,43) by functions derived from the data and then combined (47) to form a constant amplitude signal during all phases of the data signal.

Photoreceptor using mach-zehnder interferometer

The present invention relates to an optical receiver, in which the transmittance of a Mach-Zehnder interferometer can be locked at a normal operation point in a simple structure and control. A transmittance detecting circuit and a minute modulation signal detecting circuit are provided in parallel after a balanced optical receiver, and a switch is selectively connectable either a minute modulation signal detecting circuit and a transmittance detecting circuit. In the initial stage of frequency pull-in, the switch is set to connect the transmittance detecting circuit to the synchronous detection circuit. If the transmittance detecting circuit detects that the transmittance of the Mach-Zehnder interferometer at the carrier frequency becomes a desired transmittance, the connection of the switch is switched from the transmittance detecting circuit to the minute modulation signal detecting circuit.

A method of and an apparatus for effecting a smooth transition between adjacent symbol bursts transmitted in different modulation formats

평활한 트랜지션은, 송신될 제 1 디지털 심볼 버스트에 대한 제 1 시퀀스를 선택함으로써 상이한 변조 포맷으로 송신될 인접한 디지털 정보 버스트들 사이에서 달성되며, 그 제 1 시퀀스는 제 1 특정 심볼 패턴을 갖는 종료 심볼의 세트를 포함한다. 또한, 제 2 디지털 심볼 버스트에 대한 제 2 시퀀스는 그 제 1 디지털 심볼 버스트 이후에 송신을 위해 선택되며, 그 제 2 시퀀스는 제 2 특정 심볼 패턴을 갖는 시작 심볼의 세트를 포함한다. 그 제 1 디지털 심볼 버스트는 제 1 변조 포맷으로 변조되고 그 제 2 디지털 심볼 버스트는 그 제 1 변조 포맷과는 상이한 제 2 변조 포맷으로 변조된다. 그 후, 그 변조된 제 1 및 제 2 디지털 심볼 버스트가 송신된다. 그 제 2 디지털 심볼 버스트의 송신은, 제 1 코드 시퀀스의 비트들 중 종료 세트의 송신이 그 제 2 코드 시퀀스의 비트들 중 시작 세트에 맞추어 동기화되도록 선택되기 위해 일 인스턴트에서 그 제 1 디지털 심볼의 송신의 완료 시에 시작한다. 평활한 트랜지션, GMSK 버스트, 8PSK 버스트

Photoreceptor using mach-zehnder interferometer

Phase modulator

Multi-step phase shift modulator demodulator

A multi-phase shift modulator-demodulator system employs a pair of pulse trains as the information source for phase modulating a carrier wave. The phase differences between selected bit positions of the pulse trains are employed to modulate the carrier wave through the use of typical ring modulators. In the demodulator phase comparison and delay circuitry is employed to extract the clock frequency for removing the information pulse trains.

Frequency synthesis loop having controlled loop gain

A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.