Amplifier offset cancellation using amplifier supply voltage

System and method for implementing power supply rejection and offset correction of an amplifier 9A (e.g audio amplifier) comprising generating a correction signal CORR by multiplying a quantity indicative of a power supply voltage VSUPPLY of the amplifier by a transfer function F(z) defining a response from the power supply voltage of the amplifier to an output signal of the amplifier VOUT and subtracting the correction signal (combiner 24) from a signal within a signal path of a circuit comprising the amplifier. The system/amplifier may also comprise a digital-to-analogue converter DAC (14 fig 3). The correction signal may be an analogue (figures 4, 5, 7-9) or a digital correction signal (figs 2-3 and 6) operating in the analogue or digital domain of the signal path respectively. An analogue correction signal may be applied via a multiplying digital-to-analogue converter (multiplying DAC fig 5). The quantity indicative of the power supply may also be a predicted estimate of the supply ...

Switching in an audio system with multiple playback paths

In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal.

Reducing audio artifacts in an amplifier with configurable final output stage

An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Control circuitry may reduce audio artifacts associated with switching between modes.

Switching in amplifier with configurable final output stage

An amplifier and method for amplifying audio signals has a final output stage 24 which is switchable among a plurality of modes, including a mode that is enabled by coupling an output driver 44 to an output of the final output stage. A preconditioning circuit 49 is also coupled to the output of the final output stage, and is configured to precondition at least one of a voltage or current of the output prior to coupling the output driver, to limit audio artifacts caused by mode switching. The output of the final output stage may be differential and may be clamped together during preconditioning. In an alternative arrangement the final output stage is switchable between at least first and second modes where first and second paths are coupled to the output respectively, and the preconditioning circuit is configured to perform a switching sequence to switch between first and second modes, during which the final output stage output terminals always have a known impedance. The amplifier modes ...

Enhancing dynamic range based on spectral content of signal

An analog signal path portion of a signal path may have: (i) an audio input Vin for receiving an analog signal, an audio output Vout for providing an output signal, and aselectable analog gain k/x, and may be configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain; and (ii) a digital path portion having a selectable digital gain 12 and configured to receive a digital input signal DIG_IN and convert the digital input signal into the analog signal in conformity with the selectable digital gain. A control circuit 20 may be configured to modify the digital and analog gains inresponse to an indication to switch between gain modes of the signal path. The gain switching may take place at zero-crossings in the signal. A level detection circuit 62 (and 42, fig.3) provides information to the gain controller (50, fig.3). The level detection circuit 64 may receive signal information via a filter 62, which may shape the spectral content of ...

Switching in an audio system with multiple playback paths

A system and method for selecting between a plurality of operating modes of a playback path, typically in an audio amplifier system, allows for improved efficiency and dynamic range. The system, or method, includes a playback path providing an output signal VOUT based on a received input signal VIN, where the playback path is configured to operate in a plurality of operational modes. An operational mode is selected by control circuit 28 based on a signal from within the playback path indicative of the input signal, and a signal generated from the input signal externally to the playback path. The input signal may be pulse density modulated and detection of the pulse density may further be used by the control circuit (Fig. 11) for mode selection. A multi-stage output driver may be provided, operating as a Class_D audio output stage 42 in a first operational mode and a Class_AB audio output stage 44 in a second operational mode.

Reducing audio artifacts in an amplifier with configurable final output stage

An amplifier 16 includes a first stage 22 that receives an input signal Vin and generates an intermediate signal Vint as a function of the input signal, an output stage 24 that generates an output signal Vout from the intermediate signal, and a signal feedback network 26 coupled between the amplifier output and input. The input stage 22 may include an integrator 30, 32. The output stage 24 may be switchable between at least a first mode in which the output stage generates a modulated output signal as a function of the intermediate signal, e.g. a class D amplifier mode, and a second mode in which the output stage generates an unmodulated output signal, e.g. a class AB amplifier mode. Control circuit 28 may switch between amplification modes based on a characteristic of a signal indicative of the output signal, e.g. when a magnitude of the signal crossed a threshold, or based on tracking signal peaks. Switching may also take account of the spectral content of the signal, which may be filtered ...

Reducing audio artifacts in an amplifier with configurable final output stage

Adaptation of dynamic range enhancement based on noise floor of signal

COMPARATOR TRACKING CONTROL SCHEME WITH DYNAMIC WINDOW LENGTH

A comparator tracking scheme for an analog-to-digital converter (ADC) may implement a dynamic window size by varying, over time, a number of comparators powered up to convert an analog input signal to a digital output signal. A comparator-tracking scheme may be implemented, for example, in a controller coupled to a plurality of comparators in an ADC. For example, the controller may determine a window size for the ADC and determine a window position for the ADC. The controller may then activate comparators of the ADC within a window centered at the window position and having a width of the window size. The controller may determine a window size by analyzing an output of a filter. When the filter output indicates a rapidly changing analog input signal, the controller may dynamically increase a window size of the ADC, which may increase a number of comparators powered on.

Switching in amplifier with configurable final output stage

An amplifier may include a final output stage switchable among a plurality of modes comprising a mode which is enabled by coupling an output driver to an output of the final output stage and a preconditioning circuit coupled to the output of the final output stage. The preconditioning circuit may be configured to precondition at least one of a voltage and a current of the output of the final output stage prior to coupling the output driver to the output of the final output stage to limit audio artifacts caused by switching the final output stage to the mode or may be configured to perform a switching sequence to switch between a first mode and a second mode of the plurality of modes, such that at all points of the switching sequence, output terminals of the output of the final output stage have a known impedance.

Systems and methods for reducing audio artifacts from switching between paths of a multi-path signal processing

An audio processing system may include a controller 220 and a plurality of processing paths, e.g. a first path 201a and a second path 201b, the paths being arranged to generate respective digital signals based on an analogue input signal. The first path 201a may have a lower gain and a higher noise floor than the second path 201b. The controller 220 may be configured to determine that a transition between the first path and the second path needs to occur based on the occurrence of the analogue input signal crossing a threshold, or a prediction that the input signal will cross the threshold. In response to determining that a transition between the first path and the second path needs to occur, the controller blends the transition between the ADC paths during or near zero crossing points of the analogue input signal.

Enhancing dynamic range based on spectral content of signal

Systems and methods for gain calibration of an audio signal path

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

Reducing audio artifacts in a system for enhancing dynamic range of audio signal path

Reducing audio artifacts in an amplifier with configurable final output stage

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

Cross-fading in dual-path pulse width modulation system

A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

A signal path may have an analog path portion and a digital signal path portion. The digital portion may have a selectable digitally-controlled gain and may be configured to convert a digital audio input signal into an analog input signal in conformity with the selectable digitally-controlled gain, the digital signal path portion comprising a modulator including a forward path and a feedback path. The forward path may include a loop filter for generating a filtered signal responsive to the digital audio input signal and a feedback signal, a quantizer responsive to the filtered signal for generating a quantized signal, and a first gain element configured to apply the selectable digitally-controlled gain to a signal within the forward path. The feedback path may be configured to generate the feedback signal responsive to the quantized signal, the feedback path including a second gain element having a gain inversely proportional to the selectable digitally-controlled gain.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

An audio system contains a signal path comprising an analog portion (16, fig.2) having a selectable analogue gain, and a digital portion (12, 14, fig.2) having a selectable digital gain. A controller (20, fig.2) switches the analogue gain between a first and a second analogue gain and switches the digital gain between a first and a second digital gain. The product of the first analog gain and the first digital gain is substantially equal to the product of the second analog gain and the second digital gain. The control circuit also controls an analog response of the signal path to reduce the occurrence of audio artefacts arising from the gain switching. The digital signal path portion (12, 14, fig.2) comprises a digital-to-analog converter 15 comprising a modulator. The reduction of audio artefacts is achieved by modifying the analog response of at least one of the modulator and the digital-to-analog converter for a duration of time, by bypassing a filter of the digital-to-analog converter ...

Offset calibration for amplifier and preceding circuit

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

Switching in an audio system with multiple playback paths

In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal.

Adaptation of dynamic range enhancement based on noise floor of signal

An analog signal path portion of a signal path may have: (i) an audio input Vin for receiving an analog signal, an audio output Vout for providing an output signal, and aselectable analog gain k/x, and may be configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain; and (ii) a digital path portion having a selectable digital gain 12 and configured to receive a digital input signal DIG_IN and convert the digital input signal into the analog signal in conformity with the selectable digital gain. A control circuit 20 may be configured to modify the digital and analog gains inresponse to an indication to switch between gain modes of the signal path. The control circuit may determine a noise floor of an audio signal comprising the digital input signal or a signal derived therefrom, and control modification of the digital and analog gains based on the noise floor. The noise floor may be determined by performing a fast Fourier transform (FFT) on the audio signal. The analysis may take place when the audio signal is expected to have low or zero amplitude.

Reducing audio artifacts in an amplifier with configurable final output stage

An amplifier 16 includes a first stage 22 that receives an input signal Vin and generates an intermediate signal Vint as a function of the input signal, an output stage 24 that generates an output signal Vout from the intermediate signal, and a signal feedback network 26 coupled between the amplifier output and input. The input stage 22 may include an integrator 30, 32. The output stage 24 may be switchable between at least a first mode in which the output stage generates a modulated output signal as a function of the intermediate signal, e.g. a class D amplifier mode, and a second mode in which the output stage generates an unmodulated output signal, e.g. a class AB amplifier mode. Control circuit 28 may switch between amplification modes based on a characteristic of a signal indicative of the output signal, e.g. when a magnitude of the signal crossed a threshold, or based on tracking signal peaks. Switching may also take account of the spectral content of the signal, which may be filtered ...

Systems and methods for gain calibration of an audio signal path

A signal path may operate in one of a plurality of gain modes such that for each gain mode, the product of a digital gain and an analog signal gain of the signal path associated with the particular gain mode are approximately equal to a fixed path gain. During each of one or more calibration phases, a calibration system may measure analog signals at a plurality of nodes of the first path portion, calculate an actual analog gain associated with the gain mode based on the analog signals measured at the plurality of nodes, calculate an error between the fixed path gain and a mathematical product of the actual analog gain associated with the gain mode and the digital gain associated with the gain mode, and modify at least one of the digital gain and the analog gain associated with the gain mode in conformity with the error.

Systems and methods for reducing audio artifacts from switching between paths of a multi-path signal processing system

Amplifier offset cancellation using amplifier supply voltage

System and method for implementing power supply rejection and offset correction of an amplifier 9A (e.g audio amplifier) comprising generating a correction signal CORR by multiplying a quantity indicative of a power supply voltage VSUPPLY of the amplifier by a transfer function F(z) defining a response from the power supply voltage of the amplifier to an output signal of the amplifier VOUT and subtracting the correction signal (combiner 24) from a signal within a signal path of a circuit comprising the amplifier. The system/amplifier may also comprise a digital-to-analogue converter DAC (14 fig 3). The correction signal may be an analogue (figures 4, 5, 7-9) or a digital correction signal (figs 2-3 and 6) operating in the analogue or digital domain of the signal path respectively. An analogue correction signal may be applied via a multiplying digital-to-analogue converter (multiplying DAC fig 5). The quantity indicative of the power supply may also be a predicted estimate of the supply ...

Offset calibration for amplifier and preceding circuit

An apparatus, and method of operation, comprises a closed loop amplifier 16, a signal processing block 14 generating an amplifier input signal VIN from a received input signal, and a calibration subsystem 28. The amplifier, e.g. audio amplifier, includes a first stage 22 generating an intermediate signal VINT from the received input signal, a second stage 42 generating an output signal VOUT from the intermediate signal, and an input network 24 and feedback network 26 configured to set a gain of the amplifier. In a calibration mode, the calibration subsystem decouples the first stage output from the second stage input, and determines an offset signal (CAL) that, when applied to the input of the signal processing block, generates approximately zero as the intermediate signal. The offset signal may be determined at two different amplifier gains. Based on the offset signal, one or more parameters of the apparatus are controlled by the calibration subsystem to compensate for an offset of at ...

SYSTEMS AND METHODS FOR GAIN CALIBRATION OF AN AUDIO SIGNAL PATH

A signal path may operate in one of a plurality of gain modes such that for each gain mode, the product of a digital gain and an analog signal gain of the signal path associated with the particular gain mode are approximately equal to a fixed path gain. During each of one or more calibration phases, a calibration system may measure analog signals at a plurality of nodes of the first path portion, calculate an actual analog gain associated with the gain mode based on the analog signals measured at the plurality of nodes, calculate an error between the fixed path gain and a mathematical product of the actual analog gain associated with the gain mode and the digital gain associated with the gain mode, and modify at least one of the digital gain and the analog gain associated with the gain mode in conformity with the error. 1. An integrated circuit , comprising: a first path portion comprising an amplifier having an audio input for receiving an analog input signal, an audio output for providing an output signal, and an analog gain selected from a plurality of analog gains in accordance with a gain mode, and configured to generate the output signal based on the analog input signal and in conformity with the analog gain; and', 'a second path portion having a digital gain selected from a plurality of digital gains in accordance with the gain mode and configured to convert a digital audio input signal into the analog input signal in conformity with the digital gain;', 'wherein the gain mode is selected from a plurality of gain modes such that for each particular gain mode of the plurality of gain modes, the product of the digital gain associated with the particular gain mode and the analog signal gain associated with the particular gain mode are approximately equal to a fixed path gain; and, 'a signal path comprising measure analog signals at a plurality of nodes of the first path portion;', 'calculate an actual analog gain associated with the gain mode based on the analog ...

SYSTEMS AND METHODS FOR REDUCING AUDIO ARTIFACTS FROM SWITCHING BETWEEN PATHS OF A MULTI-PATH SIGNAL PROCESSING SYSTEM

A processing path may include a controller and a plurality of processing paths including a first processing path and a second processing path. The first path may be configured to generate a first digital signal based on an analog input signal and the second path may be configured to generate a second digital signal based on the analog input signal, wherein the first path has a lower gain and a higher noise floor than the second path. The controller may be configured to determine that a transition between the first path and the second path needs to occur based on the analog input signal crossing a threshold or a prediction that the input signal will cross the threshold and in response to determining the transition between the first path and the second path needs to occur, blend the transition during or near zero cross points of the analog input signal. 1. A processing system comprising: the first processing path is configured to generate a first digital signal based on an analog input signal; and', 'the second processing path is configured to generate a second digital signal based on the analog input signal; and', 'wherein the first processing path has a lower gain and a higher noise floor than the second processing path;, 'a plurality of processing paths including a first processing path and a second processing path, wherein determine that a transition between the first processing path and the second processing path needs to occur based on the analog input signal crossing a threshold or a prediction that the input signal will cross the threshold;', 'in response to determining the transition between the first processing path and the second processing path needs to occur, blend the transition during or near zero cross points of the analog input signal., 'a controller configured to2. The processing system of comprising:a controller further configured to, transition continuously or in a plurality of steps the digital output signal between the first digital signal and ...

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

Polymorphic playback system with signal detection filters of different latencies

A polymorphic playback system is disclosed in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path, wherein the polymorphic playback system may include a lower-latency detection filter, a higher-latency detection filter, and a control subsystem that uses the lower-latency detection filter for detecting the one or more first characteristics of the playback signal and uses the higher-latency detection filter for detecting the one or more second characteristics of the playback signal.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path. A signal path may have an analog path portion and a digital signal path portion. The digital portion may have a selectable digitally-controlled gain and may be configured to convert a digital audio input signal into an analog input signal in conformity with the selectable digitally-controlled gain, the digital signal path portion comprising a modulator including a forward path and a feedback path. The forward path may include a loop filter for generating a filtered signal responsive to the digital audio input signal and a feedback signal, a quantizer responsive to the filtered signal for generating a quantized signal, and a first gain element configured to apply the selectable digitally-controlled gain to a signal within the forward path. The feedback path may be configured to generate the feedback signal responsive to the quantized signal, the feedback path including a second gain element having a gain inversely proportional to the selectable digitally-controlled gain.

Systems and methods for measuring inductor current in a switching DC-to-DC converter

A switch control circuit may be utilized for a sequence of switching events: a first event to activate a first switch and deactivate a second switch, wherein a current of an inductor coupled to the first switch and the second switch increases during the first event and has a positive value at an end of the first event; a second event to deactivate the first switch and activate the second switch, wherein the current of an inductor coupled to the first switch and the second switch decreases during the second event; and an impedance event during one of the first event and the second event such that during one of the first event and the second event, the impedance event causes an impedance of the one of the first switch and the second switch to decrease.

Systems and methods for gain calibration of an audio signal path

A signal path may operate in one of a plurality of gain modes such that for each gain mode, the product of a digital gain and an analog signal gain of the signal path associated with the particular gain mode are approximately equal to a fixed path gain. During each of one or more calibration phases, a calibration system may measure analog signals at a plurality of nodes of the first path portion, calculate an actual analog gain associated with the gain mode based on the analog signals measured at the plurality of nodes, calculate an error between the fixed path gain and a mathematical product of the actual analog gain associated with the gain mode and the digital gain associated with the gain mode, and modify at least one of the digital gain and the analog gain associated with the gain mode in conformity with the error.

REDUCING AUDIO ARTIFACTS IN A SYSTEM FOR ENHANCING DYNAMIC RANGE OF AUDIO SIGNAL PATH

In accordance with embodiments of the present disclosure, an apparatus for providing an output signal to an audio transducer may include a control circuit. The control circuit may be configured to predict, based on a magnitude of a signal indicative of the output signal, an occurrence of an event for changing a selectable digital gain and a selectable analog gain and an audio signal path, and responsive to predicting the occurrence of the event, change, at an approximate time in which a zero crossing of the signal indicative of the output signal occurs, the selectable digital gain and the selectable analog gain. 1. An apparatus for providing an output signal to an audio transducer , comprising: an analog signal path portion having an audio input for receiving an analog signal, an audio output for providing an output signal, and a selectable analog gain, and configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain; and', 'a digital path portion having a selectable digital gain and configured to receive a digital input signal and convert the digital input signal into the analog signal in conformity with the selectable digital gain; and, 'a signal path comprising predict, based on one or more characteristics of a signal indicative of the output signal, an occurrence of a condition for changing the selectable digital gain and the selectable analog gain; and', 'responsive to predicting the occurrence of the condition, change, at an approximate zero crossing of the signal indicative of the output signal, the selectable digital gain and the selectable analog gain., 'a control circuit configured to2. The apparatus of claim 1 , wherein the condition for changing the selectable digital gain and the selectable analog gain comprises the magnitude of the signal indicative of the output signal crossing a predetermined threshold magnitude.3. The apparatus of claim 2 , wherein the control circuit is configured to predict ...

Switching in amplifier with configurable final output stage

An amplifier may include a final output stage switchable among a plurality of modes comprising a mode which is enabled by coupling an output driver to an output of the final output stage and a preconditioning circuit coupled to the output of the final output stage. The preconditioning circuit may be configured to precondition at least one of a voltage and a current of the output of the final output stage prior to coupling the output driver to the output of the final output stage to limit audio artifacts caused by switching the final output stage to the mode or may be configured to perform a switching sequence to switch between a first mode and a second mode of the plurality of modes, such that at all points of the switching sequence, output terminals of the output of the final output stage have a known impedance.

SYSTEMS AND METHODS FOR REDUCTION OF AUDIO ARTIFACTS IN AN AUDIO SYSTEM WITH DYNAMIC RANGE ENHANCEMENT

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path. 1. An apparatus for providing an output signal to an audio transducer , comprising: an analog signal path portion having an audio input for receiving an analog input signal, an audio output for providing the output signal, and a selectable analog gain, and configured to generate the output signal based on the analog input signal and in conformity with the selectable analog gain; and', 'a digital signal path portion having a selectable digital gain and configured to convert a digital audio input signal into the analog input signal in conformity with the selectable digital gain; and, 'a signal path comprising switch the selectable analog gain between a first analog gain and a second analog gain;', 'switch the selectable digital gain between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain; and', 'control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path., 'a control circuit ...

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

Full-scale range enhancement in a dual-path pulse width modulation playback system

A method may include, in a system comprising a digital PWM subsystem having a tunable digital gain, a first path coupled to an output of the digital PWM subsystem and configured to drive an open-loop driver stage, and a second path coupled to the output of the digital PWM subsystem and configured to drive a closed-loop driver stage having a tunable analog gain: selecting one of the first path and the second path for processing an input signal to generate an output signal based on one or more characteristics of the input signal, setting the digital gain to a maximum digital gain and the analog gain to a minimum analog gain when the input signal is lesser than a first threshold, setting the digital gain to a minimum digital gain and the analog gain to a maximum analog gain when the input signal is greater than a second threshold magnitude, and varying the analog gain and the digital gain when the input signal is in a range greater than the first threshold and lesser than a second threshold ...

Systems and methods for measuring inductor current in a switching DC-to-DC converter

A switch control circuit may be utilized for a sequence of switching events occurring in an order of a first event, a second event, a third event, and a fourth event: the first event to activate the first switch and deactivate the second switch wherein an inductor current increases during the first event and has a positive value at an end of the first event, the second event to deactivate the first switch and activate the second switch wherein the switch control circuit maintains the current above zero during the second event, the third event to activate the first switch and deactivate the second switch, and the fourth event to deactivate the first switch and activate the second switch wherein the current decreases to a value below zero at an end of the fourth event and when the current reaches zero, a zero crossing time point is defined.

Comparator tracking control scheme with dynamic window length

A comparator tracking scheme for an analog-to-digital converter (ADC) may implement a dynamic window size by varying, over time, a number of comparators powered up to convert an analog input signal to a digital output signal. A comparator-tracking scheme may be implemented, for example, in a controller coupled to a plurality of comparators in an ADC. For example, the controller may determine a window size for the ADC and determine a window position for the ADC. The controller may then activate comparators of the ADC within a window centered at the window position and having a width of the window size. The controller may determine a window size by analyzing an output of a filter. When the filter output indicates a rapidly changing analog input signal, the controller may dynamically increase a window size of the ADC, which may increase a number of comparators powered on.

Enhancing dynamic range based on spectral content of signal

In accordance with embodiments of the present disclosure, an apparatus for providing an output signal to an audio transducer may include a signal path and a control circuit. The signal path may include an analog signal path portion having an audio input for receiving an analog signal, an audio output for providing an output signal, and a selectable analog gain, and configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain and a digital path portion having a selectable digital gain and configured to receive a digital input signal and convert the digital input signal into the analog signal in conformity with the selectable digital gain. The control circuit may be configured to determine a spectral content of a signal indicative of the output signal and change the selectable digital gain and the selectable analog gain based on the spectral content.

Signal amplitude-selected signal predistortion in an amplifier

An amplification system with an output driver stage for providing an output signal to acoustic output transducers such as speakers or haptic output devices removes signal distortion caused by output stage non-linearities by pre-distorting an input signal. The system includes the output driver stage, an input stage for receiving the input signal, and a processing block that receives the input signal and provides an output signal to the output driver stage. The processing block includes a pre-distortion circuit that applies a pre-distortion function to the input signal to generate the output signal if a signal level of the input signal is greater than a threshold amplitude, and if the signal level is less than or equal to the threshold amplitude, generates the output signal from the input signal by bypassing the pre-distortion circuit.

Low-latency audio output with variable group delay

A system may include a filter configured to receive a digital audio input signal quantized at between two and 257 quantization levels and sampled at at least 500 kilohertz, the filter further configured to perform filtering on the digital audio input signal to generate a filtered digital audio input signal, the filter having a selectable variable group delay, a digital-to-analog converter configured to receive the filtered digital audio input signal and convert the filtered digital audio input signal into an equivalent analog audio input signal, and a driver configured to receive the equivalent analog audio input signal and drive an analog audio output signal to a transducer.

Reducing audio artifacts in a system for enhancing dynamic range of audio signal path

In accordance with embodiments of the present disclosure, an apparatus for providing an output signal to an audio transducer may include a control circuit. The control circuit may be configured to predict, based on a magnitude of a signal indicative of the output signal, an occurrence of an event for changing a selectable digital gain and a selectable analog gain and an audio signal path, and responsive to predicting the occurrence of the event, change, at an approximate time in which a zero crossing of the signal indicative of the output signal occurs, the selectable digital gain and the selectable analog gain.

Polymorphic playback system with switching oscillation prevention

A polymorphic playback system in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path may include a control subsystem configured to detect an out-of-band noise profile of the playback signal and set one or more playback signal magnitude thresholds for switching between polymorphic modes of the polymorphic playback system based on the out-of-band noise profile, wherein the polymorphic modes comprise at least a first polymorphic mode in which one or more first parameters are applied to the signal path and a second polymorphic mode in which one or more second parameters are applied to the signal path.

SYSTEMS AND METHODS FOR REDUCTION OF AUDIO ARTIFACTS IN AN AUDIO SYSTEM WITH DYNAMIC RANGE ENHANCEMENT

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path. 127.-. (canceled)28. An apparatus for providing an output signal to an audio transducer , comprising: an analog signal path portion having an audio input for receiving an analog input signal, an audio output for providing the output signal, and a selectable analog gain, and configured to generate the output signal based on the analog input signal and in conformity with the selectable analog gain; and', [ a loop filter configured to generate a filtered signal responsive to the digital audio input signal and a feedback signal; and', 'a quantizer responsive to the filtered signal and configured to generate a quantized signal; and, 'a forward path comprising, 'a feedback path configured to generate the feedback signal responsive to the quantized signal, wherein the feedback path includes a first gain element having a selectable first digitally-controlled gain such that a signal gain of the modulator is inversely proportional to the selectable analog gain; and, 'a digital signal path portion having a selectable digitally-controlled gain and configured to convert a digital audio input signal into the analog input signal in conformity with the selectable ...

Systems and methods for reducing audio artifacts from switching between paths of a multi-path signal processing system

A processing path may include a controller and a plurality of processing paths including a first processing path and a second processing path. The first path may be configured to generate a first digital signal based on an analog input signal and the second path may be configured to generate a second digital signal based on the analog input signal, wherein the first path has a lower gain and a higher noise floor than the second path. The controller may be configured to determine that a transition between the first path and the second path needs to occur based on the analog input signal crossing a threshold or a prediction that the input signal will cross the threshold and in response to determining the transition between the first path and the second path needs to occur, blend the transition during or near zero cross points of the analog input signal.

Reducing audio artifacts in an amplifier with configurable final output stage

An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Control circuitry may reduce audio artifacts associated with switching between modes.

SIGNAL AMPLITUDE-SELECTED SIGNAL PREDISTORTION IN AN AMPLIFIER

An amplification system with an output driver stage for providing an output signal to acoustic output transducers such as speakers or haptic output devices removes signal distortion caused by output stage non-linearities by pre-distorting an input signal. The system includes the output driver stage, an input stage for receiving the input signal, and a processing block that receives the input signal and provides an output signal to the output driver stage. The processing block includes a pre-distortion circuit that applies a pre-distortion function to the input signal to generate the output signal if a signal level of the input signal is greater than a threshold amplitude, and if the signal level is less than or equal to the threshold amplitude, generates the output signal from the input signal by bypassing the pre-distortion circuit.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path. A signal path may have an analog path portion and a digital signal path portion. The digital portion may have a selectable digitally-controlled gain and may be configured to convert a digital audio input signal into an analog input signal in conformity with the selectable digitally-controlled gain, the digital signal path portion comprising a modulator including a forward path and a feedback path. The forward path may include a loop filter for generating a filtered signal responsive to the digital audio input signal and a feedback signal, a quantizer responsive to the filtered signal for generating a quantized signal, and a first gain element configured to apply the selectable digitally-controlled gain to a signal within the forward path. The feedback path may be configured to generate the feedback signal responsive to the quantized signal, the feedback path including a second gain element having a gain inversely proportional to the selectable digitally-controlled gain.

AUDIO PROCESSING SYTEM SIGNAL-LEVEL BASED TEMPORAL MASKING

An audio processing system reduces perception of audible artifacts due to changes in an element in an audio channel of the audio processing system. The system reproduces an audio input signal and produces an audio output signal with the audio channel. The channel has an adjustable or selectable element that, responsive to a control signal, changes a characteristic of the audio processing channel, which generates a transient in the audio output signal. The systems include a level detector for measuring a signal level of the audio input signal and a controller responsive to an output of the level detector to determine a masking time interval available from the audio output signal due to signal content in the audio input signal. The controller generates the control signal to change the characteristic of the audio processing channel so that at least a portion of the transient occurs in the masking time interval. 1. An audio processing system , comprising:an audio processing channel having an input for receiving an audio input signal and producing an audio output signal, wherein the audio processing channel has an adjustable or selectable element that changes a characteristic of the audio processing channel that generates a transient in the audio output signal, wherein the adjustable or selectable element is responsive to a control signal to change the characteristic;a signal level detector for measuring a signal level of the audio input signal; anda controller responsive to an output of the signal level detector to determine a masking time interval available from the audio output signal due to signal content in the audio input signal and that generates the control signal to change the characteristic of the audio processing channel so that at least a portion of the transient occurs in the masking time interval.2. The audio processing system of claim 1 , wherein the masking time interval is a time interval commenced in response to a drop in the signal level measured by ...

Switching in an audio system with multiple playback paths

In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal.

POLYMORPHIC PLAYBACK SYSTEM WITH SIGNAL DETECTION FILTERS OF DIFFERENT LATENCIES

A polymorphic playback system is disclosed in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path, wherein the polymorphic playback system may include a lower-latency detection filter, a higher-latency detection filter, and a control subsystem that uses the lower-latency detection filter for detecting the one or more first characteristics of the playback signal and uses the higher-latency detection filter for detecting the one or more second characteristics of the playback signal.

Adjusting peak inductor current to limit supply input current

A method may include monitoring an input power supply, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating a target peak inductor current based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a target average current of the inductor during a switching cycle of the boost converter. A method may include monitoring an input power supply voltage, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating an average current of the inductor during a switching cycle of the boost converter based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a peak inductor current of the inductor.

CARPOOL ARRANGER AND METHOD OF OPERATION

The present invention is a carpool arranger and a method of operating the carpool arranger. The carpool arranger comprises at least one passenger internet device, at least one vehicle internet device and a central processing module. The method of operating the carpool arranger comprises steps of transmitting information from each passenger internet device and each vehicle internet device to a central processing module; planning an optimal route for a passenger internet device that transmits a carpool request; choosing appropriate vehicles; planning carpool routes for the chosen vehicles; and transmitting information from the central processing module to each passenger internet device and each vehicle internet device. 1. A carpool arranger having at least one potential passenger and at least one vehicle and comprisingat least one potential passenger internet device having a global positioning system unit and a communication unit;at least one vehicle internet device having a global positioning system unit and a communication unit; anda central processing module that has a passenger database, a vehicle database, a route planning unit that plans a carpool route for each vehicle such that original route of each vehicle is a subset of the planned carpool route, an expense calculating unit and a communication unit.2. The carpool arranger as claimed in claim 1 , wherein the communication unit of the user communication device transmits information of carpool request and passenger pick-up point claim 1 , drop-off point and parameters and receives information.3. The carpool arranger as claimed in claim 1 , wherein the communication unit of the vehicle internet device transmits information of vehicle position and status and receives information.4. The carpool arranger as claimed in claim 1 , wherein the passenger internet device is a cell-phone.5. The carpool arranger as claimed in claim 1 , wherein the passenger internet device is a computer.6. The carpool arranger as claimed ...

CARPOOL FARE ORGANIZER AND METHOD FOR GENERATING CARPOOL FARES

A carpool fare organizer is useful when there is at least one passenger and comprises a distance recording unit, a passenger calculating unit, a fare calculating module and at least one display device. The distance recording unit records a get-in distance, a get-out distance and an accumulated distance of each passenger. The passenger calculating unit calculates a number of passengers. The fare calculating module calculates an original fare, an accumulated discount and an economical fare. A method for generating carpool fares comprises steps of recording a get-in distance, a get-out distance and an accumulated distance of each passenger and a number of passengers, and calculating an economical fare with the get-in distance, the get-out distance, the accumulated distance and the number of passengers.

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

Adaptation of dynamic range enhancement based on noise floor of signal

An analog signal path portion of a signal path may have: (i) an audio input for receiving an analog signal, an audio output for providing an output signal, and a selectable analog gain, and may be configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain; and (ii) a digital path portion having a selectable digital gain and configured to receive a digital input signal and convert the digital input signal into the analog signal in conformity with the selectable digital gain. A control circuit may be configured to modify the digital and analog gains in response to an indication to switch between gain modes of the signal path, determine a noise floor of an audio signal comprising the digital input signal or a signal derived therefrom, and control modification of the digital and analog gains based on the noise floor.

OFFSET CALIBRATION FOR AMPLIFIER AND PRECEDING CIRCUIT

A method may include, in an apparatus comprising a closed loop amplifier and a signal processing block configured to generate an amplifier input signal as a function of an upstream signal received at an input of the signal processing block, in a calibration mode of the apparatus: decoupling a second stage input of the amplifier from a first stage output of the amplifier; determining an offset signal that when applied to the input of a signal processing block as the upstream signal generates approximately zero as an intermediate signal generated by the first stage of the amplifier; and controlling one or more parameters of the apparatus based on the offset signal to compensate for an offset of at least one of the first stage and the signal processing block. 1. An apparatus comprising: a first stage configured to receive an amplifier input signal at an amplifier input and generate at a first stage output an intermediate signal which is a function of the amplifier input signal;', 'a second stage configured to receive the intermediate signal at a second stage input and configured to generate at a second stage output an output signal from the intermediate signal which is a function of the amplifier input signal; and', 'an input network and a feedback network configured to set a gain of the closed loop amplifier;, 'a closed loop amplifier comprisinga signal processing block configured to generate the amplifier input signal as a function of an upstream signal received at an input of the signal processing block; and decouple the second stage input from the first stage output;', 'determine an offset signal that when applied to the input of the signal processing block as the upstream signal generates approximately zero as the intermediate signal; and', 'control one or more parameters of the apparatus based on the offset signal to compensate for an offset of at least one of the first stage and the signal processing block., 'a calibration subsystem configured to, in a ...

FULL-SCALE RANGE ENHANCEMENT IN A DUAL-PATH PULSE WIDTH MODULATION PLAYBACK SYSTEM

A method may include, in a system comprising a digital PWM subsystem having a tunable digital gain, a first path coupled to an output of the digital PWM subsystem and configured to drive an open-loop driver stage, and a second path coupled to the output of the digital PWM subsystem and configured to drive a closed-loop driver stage having a tunable analog gain: selecting one of the first path and the second path for processing an input signal to generate an output signal based on one or more characteristics of the input signal, setting the digital gain to a maximum digital gain and the analog gain to a minimum analog gain when the input signal is lesser than a first threshold, setting the digital gain to a minimum digital gain and the analog gain to a maximum analog gain when the input signal is greater than a second threshold magnitude, and varying the analog gain and the digital gain when the input signal is in a range greater than the first threshold and lesser than a second threshold. 1. A system comprising:a digital pulse width modulator subsystem having a tunable digital gain;a first path coupled to an output of the digital pulse width modulator subsystem and configured to drive an open-loop driver stage;a second path coupled to the output of the digital pulse width modulator subsystem and configured to drive a closed-loop driver stage having a tunable analog gain, wherein the open-loop driver stage and the closed-loop driver stage are powered from a low-dropout (LDO) regulator that generates a supply voltage shared by the open-loop driver stage and the closed-loop driver stage; and select one of the first path and the second path for processing an input signal to generate an output signal based on one or more characteristics of the input signal;', 'set the tunable digital gain to a maximum tunable digital gain and the tunable analog gain to a minimum tunable analog gain to compensate for an LDO attenuation of the LDO regulator when a magnitude of the input ...

SWITCHING IN AN AUDIO SYSTEM WITH MULTIPLE PLAYBACK PATHS

In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal. 1. (canceled)2. A system comprising: the playback path is configured to operate in a plurality of operational modes; and', 'the playback path comprises an inline filter configured to filter the input signal to generate a first filtered input signal; and, 'a playback path having a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein receive a first signal from within the playback path and indicative of the input signal and the first filtered input signal;', 'receive a second signal generated from the input signal externally to the playback path; and', 'select a selected operational mode from the plurality of operational modes based on the first signal and the second signal., 'a control circuit configured to3. The system of claim 2 , further comprising an offline filter external to the playback path and configured to filter the input signal to generate a second filtered input signal claim 2 , and wherein the second signal is indicative of the second filtered input signal.4. The system of claim 3 , wherein the control circuit is configured to switch the selected operational mode in response to one of the first signal crossing a first predetermined threshold and ...

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

A system and a method for carpool fares

Switching in amplifier with configurable final output stage

An amplifier may include a final output stage switchable among a plurality of modes comprising a mode which is enabled by coupling an output driver to an output of the final output stage and a preconditioning circuit coupled to the output of the final output stage. The preconditioning circuit may be configured to precondition at least one of a voltage and a current of the output of the final output stage prior to coupling the output driver to the output of the final output stage to limit audio artifacts caused by switching the final output stage to the mode or may be configured to perform a switching sequence to switch between a first mode and a second mode of the plurality of modes, such that at all points of the switching sequence, output terminals of the output of the final output stage have a known impedance.

Reducing audio artifacts in an amplifier with configurable final output stage

An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Control circuitry may reduce audio artifacts associated with switching between modes.

Signal amplitude-selected signal pre-distortion in an amplifier

Signal amplitude-selected signal pre-distortion in an amplifier

An amplification system 10 for providing an output drive signal to an acoustic output transducer, comprising: an input stage for receiving an input signal to be amplified; an output driver stage for providing the drive signal to the transducer; and a processing block 20 for receiving the input signal IN and providing an output signal OUT A, OUT B to the driver stage. The processing block comprises a pre-distortion circuit (20A, fig 2, 20B, fig 3) that applies a pre-distortion function to the input signal to generate the modified output signal if a signal level of the input signal is greater than a threshold amplitude, and if the signal level is less than or equal to the threshold amplitude, generates the output signal from the input signal by bypassing the pre-distortion circuit. A method of reducing distortion in an amplifier is also provided. The pre-distortion circuit may be disabled if the signal level is below the threshold amplitude. The modified signal may be computed by applying a polynomial or telescoped polynomial to values of the input signal. The system may have a second threshold amplitude less than the first threshold amplitude by an amplitude hysteresis value. The amplifier may include multiple amplification paths which are selectively enabled.

Systems and methods for gain calibration of an audio signal path

A signal path may operate in one of a plurality of gain modes such that for each gain mode, the product of a digital gain and an analog signal gain of the signal path associated with the particular gain mode are approximately equal to a fixed path gain. During each of one or more calibration phases, a calibration system may measure analog signals at a plurality of nodes of the first path portion, calculate an actual analog gain associated with the gain mode based on the analog signals measured at the plurality of nodes, calculate an error between the fixed path gain and a mathematical product of the actual analog gain associated with the gain mode and the digital gain associated with the gain mode, and modify at least one of the digital gain and the analog gain associated with the gain mode in conformity with the error.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

An audio system contains a signal path comprising an analog portion (16, fig.2) having a selectable analogue gain, and a digital portion (12, 14, fig.2) having a selectable digital gain. A controller (20, fig.2) switches the analogue gain between a first and a second analogue gain and switches the digital gain between a first and a second digital gain. The product of the first analog gain and the first digital gain is substantially equal to the product of the second analog gain and the second digital gain. The control circuit also controls an analog response of the signal path to reduce the occurrence of audio artefacts arising from the gain switching. The digital signal path portion (12, 14, fig.2) comprises a digital-to-analog converter 15 comprising a modulator. The reduction of audio artefacts is achieved by modifying the analog response of at least one of the modulator and the digital-to-analog converter for a duration of time, by bypassing a filter of the digital-to-analog converter. The response may be modified by activating a switch 17 to bypass a low-pass filter of the DAC.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path.

Adjusting peak inductor current to limit supply input current

A method may include monitoring an input power supply, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating a target peak inductor current based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a target average current of the inductor during a switching cycle of the boost converter. A method may include monitoring an input power supply voltage, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating an average current of the inductor during a switching cycle of the boost converter based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a peak inductor current of the inductor.

Audio processing system signal-level based temporal masking

An audio processing system reduces perception of audible artifacts due to changes in an element in an audio channel of the audio processing system. The system reproduces an audio input signal and produces an audio output signal with the audio channel. The channel has an adjustable or selectable element that, responsive to a control signal, changes a characteristic of the audio processing channel, which generates a transient in the audio output signal. The systems include a level detector for measuring a signal level of the audio input signal and a controller responsive to an output of the level detector to determine a masking time interval available from the audio output signal due to signal content in the audio input signal. The controller generates the control signal to change the characteristic of the audio processing channel so that at least a portion of the transient occurs in the masking time interval.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

Amplifier offset cancellation using amplifier supply voltage

Amplifier offset cancellation using amplifier supply voltage

In accordance with embodiments of the present disclosure, a method for power supply rejection for an amplifier may include generating a correction signal by multiplying a quantity indicative of a power supply voltage of the amplifier by a transfer function defining a response from the power supply voltage of the amplifier to an output signal of the amplifier and subtracting the correction signal from a signal within a signal path of a circuit comprising the amplifier.

Systems and methods for reduction of audio artifacts in an audio system with dynamic range enhancement

In accordance with embodiments of the present disclosure, a control circuit may be configured to, responsive to an indication to switch between gain modes of a signal path having an analog path portion and a digital signal path portion, switch a selectable analog gain of the analog path portion between a first analog gain and a second analog gain, switch a selectable digital gain of the digital signal path portion between a first digital gain and a second digital gain, wherein the product of the first analog gain and the first digital gain is approximately equal to the product of the second analog gain and the second digital gain, and control an analog response of the signal path to reduce the occurrence of audio artifacts present in the output signal as a result of the switch between gain modes of the signal path.

Comparator tracking control scheme with dynamic window length

A comparator tracking scheme for an analog-to-digital converter (ADC) may implement a dynamic window size by varying, over time, a number of comparators powered up to convert an analog input signal to a digital output signal. A comparator-tracking scheme may be implemented, for example, in a controller coupled to a plurality of comparators in an ADC. For example, the controller may determine a window size for the ADC and determine a window position for the ADC. The controller may then activate comparators of the ADC within a window centered at the window position and having a width of the window size. The controller may determine a window size by analyzing an output of a filter. When the filter output indicates a rapidly changing analog input signal, the controller may dynamically increase a window size of the ADC, which may increase a number of comparators powered on.

動的ウィンドウ長さを用いるコンパレータ追跡制御方式

【課題】動的ウィンドウ長さを用いるコンパレータ追跡制御方式の提供。【解決手段】アナログ／デジタルコンバータ（ＡＤＣ）のためのコンパレータ追跡方式は、経時的に、アナログ入力信号をデジタル出力信号に変換するためにパワーアップされるコンパレータの数を変動させることによって、動的ウィンドウサイズを実装し得る。コンパレータ追跡方式は、例えば、ＡＤＣ内の複数のコンパレータに結合されるコントローラ内に実装され得る。例えば、コントローラは、ＡＤＣのためのウィンドウサイズを判定し、かつＡＤＣのためのウィンドウ位置を判定し得る。コントローラは、次いで、そのウィンドウ位置を中心とし、ある幅のウィンドウサイズを有する、ウィンドウ内のＡＤＣのコンパレータをアクティブ化し得る。コントローラは、フィルタの出力を分析することによってウィンドウサイズを判定し得る。【選択図】図４

Comparator tracking control scheme with dynamic window length

A comparator tracking scheme for an analog-to-digital converter (ADC) may implement a dynamic window size by varying, over time, a number of comparators powered up to convert an analog input signal to a digital output signal. A comparator-tracking scheme may be implemented, for example, in a controller coupled to a plurality of comparators in an ADC. For example, the controller may determine a window size for the ADC and determine a window position for the ADC. The controller may then activate comparators of the ADC within a window centered at the window position and having a width of the window size. The controller may determine a window size by analyzing an output of a filter. When the filter output indicates a rapidly changing analog input signal, the controller may dynamically increase a window size of the ADC, which may increase a number of comparators powered on.

Switching in an audio system with multiple playback paths

Switching in an audio system with multiple playback paths

Audio processing system signal-level based temporal masking

The invention relates to an audio processing system having a channel containing selectable elements that, responsive to a control signal, change a characteristic of the channel, such as its gain. Such switching can cause transients and audible artefacts. The present invention uses the phenomenon of audio masking (mask threshold 32A, fig.4) to make such artefacts less perceptible by allowing gain, etc., to be switched only when the characteristics of the audio signal are such as to mask any artefacts that arise (fig.9). The system includes a level detector for measuring a signal level of the audio input signal. Based on the signal level, a controller determines a masking time interval during which the controller may change the characteristics of the audio channel so that at least a portion of the transient occurs in the masking time interval (figure 9).

Audio processing system signal-level based temporal masking

The invention relates to an audio processing system having a channel containing selectable elements that, responsive to a control signal, change a characteristic of the channel, such as its gain. Such switching can cause transients and audible artefacts. The present invention uses the phenomenon of audio masking (mask threshold 32A, fig.4) to make such artefacts less perceptible by allowing gain, etc., to be switched only when the characteristics of the audio signal are such as to mask any artefacts that arise (fig.9). The system includes a level detector for measuring a signal level of the audio input signal. Based on the signal level, a controller determines a masking time interval during which the controller may change the characteristics of the audio channel so that at least a portion of the transient occurs in the masking time interval (figure 9).

Audio processing system signal-level based temporal masking

Adaptation of dynamic range enhancement based on noise floor of signal

An analog signal path portion of a signal path may have: (i) an audio input for receiving an analog signal, an audio output for providing an output signal, and a selectable analog gain, and may be configured to generate the output signal based on the analog signal and in conformity with the selectable analog gain; and (ii) a digital path portion having a selectable digital gain and configured to receive a digital input signal and convert the digital input signal into the analog signal in conformity with the selectable digital gain. A control circuit may be configured to modify the digital and analog gains in response to an indication to switch between gain modes of the signal path, determine a noise floor of an audio signal comprising the digital input signal or a signal derived therefrom, and control modification of the digital and analog gains based on the noise floor.