Method for realizing automatic pattern recognition via system information
Technical Field The invention relates to a technical field of digital signal transmission method, in particular relates to a transmission of the digital terrestrial broadcasting transmission mode judging method. Background Art Wireless transmission system includes a transmitter and a receiver. Figure 1 is the system block diagram of a typical digital radio transmission, transmission process includes: the transmission end, first of all to the input digital signal is encoded, then adding the necessary auxiliary information, such as synchronization signal, the pilot signal or the like; the encoded digital signal after filtering by the channel forming a baseband signal; the baseband signal after the up-converter is modulated to a frequency band corresponding to the signal is amplified after sending. At the receiving end, the tuner (if there is a tuner, they do not need to be down-conversion, so Figure 1 in broken line show the tuner and down-converter) the high-frequency signal is converted into the baseband after the analog-to-digital converter receiving the digital signal; after processing of the digital signal (such as a digital decoding) is restored to the information of the transmitting end of the consistent output. In the digital television terrestrial broadcast transmission system, the data frame transmission different business can choose to adopt different transmission mode. Four kinds of code rates corresponding to the ground mode of transmission channel coding structure as shown in Figure 2. In the digital TV terrestrial broadcast system transmission of the signal in the method is of the: transmitted in a digital transmission system by the multi-level symbols of the data stream is divided into a a continuous transmission of the data frames of; each data frame contains 3 parts, are respectively preset information, system information and data information, and so as to form the simple one-step cycle. Wherein the system information is used for determining the mode of transmission of the frame data information, system information can also be used for future expansion of the function. System information through the two level sequence to express. The length of the system information can be chosen, but should satisfy the 2 power. Digital TV terrestrial broadcast transmission system can transmit three kinds of service, are television signal (fixed service) for fixed receivers, television signal mobile receiving (mobile service) mobile receiving and the data stream (data service). Wherein selected fixed service can 16-OQAM modulation mode or 32-OQAM modulation mode; can be selected with the mobile service 4-OQAM modulation mode or 4-OQAM-E modulation mode; data service may choose 4-OQAM-E modulation mode. Various modulation mode is explicitly pointed out that the system information. In the hybrid transmission mode, various service according to their respective modulation modes of the arbitrary mixing in units of frames, each frame by the modulation modes of the explicitly pointed out that the system information of the frame. After receiving the data receiving terminal, the frame should be based on system information to determine the modulation modes of the frame data, then make the corresponding treatment, that is, the equalizer the judgement way of corresponding modulation mode, channel decoding the corresponding modulation mode, such as a corresponding mode. This involves the according to the received signal at the receiving end to the problem of distinguishing the modulation mode. Occasions for different applications using different convolution interleaving mode, digital TV terrestrial broadcast transmission system can adopt two kinds of interleaving mode, mode 1: interleaving/deinterleaving total delay to 170 signal, mode 2: interleaving/deinterleaving total delay to 510 signal frame. Strong real-time requirement for example, system cannot be too long delay requirement, short of interleave patterns can be adopted; the need for anti-burst wrong occasion of strong, long interleave pattern can be adopted. This involves the according to the received signal at the receiving end for symbol interleaving mode judging problems. Occasions for different applications, digital television terrestrial broadcast transmission system of the channel encoding LDPC code can be made of three kinds: 0.4, 0.6, 0.8. The mobile receiving and relatively severe to the fixed receiving mode is enhanced relatively low code rate error correction effect, the better the channel conditions to the fixed receiving selecting the use of higher bit rate transmission, increase the amount of information can be transmitted. This also relates to on the basis of the received signal at the receiving end to the problem of determining a code rate LDPC. Figure 2 shows the digital TV terrestrial broadcast transmission system of the high-bit-rate the 32-QAM, 16-QAM, code rate 4-QAM and low code rate 4-QAM-NR specific examples of the frame structure of the, wherein the predetermined information is realized by PN sequence (for example 595-bit pseudo-random sequence); by the system information 4 that the second level of the added signal after 64 a 32-bit bi-level symbol sequence in the system information of a representation of the vector, each data frame contains 3744 data information of one symbol. The existing digital TV terrestrial broadcast mode of transmission of the most discriminating method of reference ATSC standard "ATSC STANDARD TELEVISION DIGITAL" or DVB-T standard "Digital Video Broadcasting (DVB); Framing structure, and channel coding for digital terrestrial television modulation". High grade digital television broadcasting in the United States ( Committee Television Systems Advanced) the 2003 years 12 months of literature in "ATSC TELEVISION STANDARD DIGITAL", mode judgement is made in the field synchronizing the 24bit. The 24bit front 16bit is a reservation bit. Rear 8bit the representative 2 of the existing transmission mode, and a 6 retention of mode. In Europe, Serial numbers are EN ETSI 300 744 V1.4.1 literature " Video Digital Broadcasting (DVB); Framing structure, channel coding modulation for digital terrestrial television and" in, the transmission mode is realized by the frequency domain of the TPS. TPS transmission information includes the current data frame of the selected channel coding and modulation mode, information. The above-mentioned ATSC and DVB-T of the transmission mode, the data can be correctly received under the condition of relatively simple to obtain system information. Of the above-mentioned ATSC and DVB-T mode of transmission, the shortcoming lies in the absence of special spread spectrum protection, it must be in the correct the premise of demodulated data transmission mode can be known. Content of the invention The present invention is directed to the deficiency in the prior art, provides a is applicable to the digital TV terrestrial broadcast transmission method for discriminating the mode of transmission. This invention, through the balanced before the pattern recognition of the data transmission, a modulation mode matching, symbol interleaving mode, the code rate LDPC coding. Moreover, this kind of method can be in signal-to-noise ratio is very low (frame data cannot be correctly demodulated) under the condition of, still mode of transmission can be judged. The purpose of this invention is realized through the following technical scheme: Transmission system of multi-level symbols by the transmission of the data stream is divided into a a continuous transmission of the data frames of; each data frame contains can be used for system synchronization, the clock recovery, the channel estimates and the equalizer training the preset information, data frames can be used for representing the information modulation mode, interleaving mode and the system information of the code rate LDPC, and the three-part data information, and so as to form the simple one-step cycle, the preset information is the m to realize PN sequence; Digital TV terrestrial broadcast transmission system comprising in a data frame of a data information representing the system information of the transmission mode, the system information after the m+n to randomize the sequence of the second level, the generation process of the sending end to: the m sure behind the two level of signal n Walsh sequence is added, containing n n-n Walsh block is a Walsh sequence, the Walsh sequence is a n n the original of the Walsh sequence to form a n 2n sequence, then the this 2n which are respectively connected with a sequence of random sequence is multiplied by n to obtain 2n a system information vector, used for showing the system information, the above-mentioned n to 2 power; a transmission mode corresponding to the system one of the information vectors, the mode bit definition of the system information of each agreement with the system information of the mode of transmission of one-to-one correspondence relationship; transmission system the receiving end the equalization processing of the data stream before the recognition of the transmission mode, including the steps of: (1) data frames of the received data flow reaches the system information bits, with n input data is multiplied by random sequence data one by one, the n bit random sequence data and system information in the process of generating the Walsh block the randomized same of random sequence; (2) after the transmission of n symbols, these symbols is multiplied by n bits corresponding to the Walsh transform result; (3) after taken out of the Walsh transform output n in one of the largest absolute value, information transmission system according to the mode word to find out its corresponding system definition information, then, according to the system information matching the transmission mode of the data frame, comprising modulation mode, interleaving mode and LDPC coding rate mode. At the transmitting end of the process of producing the above-mentioned system information can also be in the n a first n-bit Walsh sequence randomises processing, then the randomises processing generated after the method of Walsh sequence is a n 2n a system information vector, in order to indicate that the system information. The above-mentioned system information generating process for the Walsh block the randomized can be of random sequence (n-1) add PN sequence is marked "0 the random sequence of [...] ; at this moment at the receiving end for convenient processing, can be the above-mentioned step (1) in the n bit random sequence in" 0 the corresponding [...] mapped to "-1 the after [...] multiplied by the input data. The above-mentioned step (1) of the data frame in the data stream to the received system information of the starting point, the time required for processing the input data at a time when the system information bits. In the above-mentioned step (1) in, can be used for a memory for storing the random sequence data, can also use a random sequence generating unit instead of the above-mentioned memory, G31 (x) = 1 +x+ x3 + x4 + x5, the initial phase is 00001, the reset at the beginning of each signal frame. The random sequence generation unit can be made of as shown in Figure 4 the structure of the LFSR. The above-mentioned step (2) can be used in converting unit of a Walsh transform Walsh, Walsh transform to the following method can be adopted: for Walsh n×n of the block matrix with the input of the n n × 1 bit data is multiplied by a column vector, n results obtained, of the block matrix Walsh n×n for the above-mentioned the sending end in the process of generating the system information of the block matrix Walsh n×n, for convenient processing, n×n in this step of the block matrix of Walsh "0 the mapped into [...] "-1 the after [...] participate in the operation. N-bit Walsh transform to the realization of the method can also be used: the Walsh transform on and fast Fourier transform of the same algorithm, the fast Fourier transform of the coefficients in the sign bit, n results obtained. The method for realizing this is the reason for a Walsh transform algorithm and fast Fourier transform (FFT) algorithm of the same leaf. Adopting this kind of method for realizing Walsh transform in only needs to adder, multiplier-free, and the number of times of the addition operation are also less, therefore, can reduce the hardware configuration, the calculation speed is accelerated. The above-mentioned step (3) after Walsh transform used in the comparator is taken out of the output n in the one with the greatest absolute value. Pattern recognition method of the present invention can be applied to a digital TV terrestrial broadcast receiving end of the system, the pattern recognition method to the before equalization, that is to say before the equalizer operation for mode judging, matching the transmission mode. In the ATSC and DVB-T compared with the transmission mode judging method, this invention, because of the protection of the spreading sequence, gain is very high, on the receive side can be obtained in data demodulation before transmission mode. In the interference is very strong and still can work normally. Description of drawings Figure 1 is the system block diagram of a typical digital transmission of the prior art; Figure 2 is the high code rate 32-QAM, 16-QAM, code rate 4-QAM and low code rate 4-QAM-NR frame structure; Figure 3 to 5 meta-m sequence generating structure diagram; Figure 4 is the transmission mode judging method the total block diagram of the implementation of example one; Figure 5 is the transmission mode judging method the total block diagram of the implementation of example two; Figure 6 is the transmission mode judging method the total block diagram of the implementation of example three ; Figure 7 is the total diagram transmission mode judging method of implementing example four. Mode of execution The specific embodiment according to the Figures and further description of the present invention. The embodiment disclosed is the method of the present invention in a digital TV terrestrial broadcast transmission system the specific application, in this embodiment the applicable digital TV terrestrial broadcast transmission system technical scheme, transmission system of multi-level symbols by the transmission of the data stream is divided into a a continuous transmission of the data frames of; each data frame contains can be used for system synchronization, the clock recovery, the channel estimates and the equalizer training the preset information, data frames can be used for information transmission mode, interleaving mode and the system information of the code rate LDPC, and the three-part data information, and so as to form the simple one-step cycle. Ground transmission system of the digital television in the technical scheme, the system information through the two level sequence to express, its length according to the business needs of the n different and chosen, but should satisfy the 2 power. For example, under the wired transmission mode, system information may be 32 or 64 bit long, and in the wireless transmission mode, can select 64 or 1 28 bit long. The method of the present invention can be applied using the above-mentioned different length information design system in the transmission system, in order to the present invention is more convenient to be understood, the introduction of the first embodiment to be disclosed to the application of an exemplary transmission system of the technical scheme, wherein n is set to be 32: Digital TV terrestrial broadcast transmission system comprising in a data frame of a data information representing the system information of the transmission mode, the system information of the transmitting end of the generating process is as follows: 32 meta-(n=32=25) containing the Walsh block 32 a 32-bit Walsh sequence, generate a method is as follows: in the basic Walsh block Each transmission mode corresponding to the 64 system one of the information vectors, other vector as a reservation mode. For the sake of convenient processing at the receiving end, when the pattern recognition of the use of Walsh block and random sequence of in "0 the are [...] mapped to"-1 the [...]. The following discloses a transmission system adopting the design the method of pattern recognition of the receiving end. Implementation of the example one Attached Figure 4 is the total block diagram of the implementation of the method, in the implementation of the method, a length of 32 bits of memory storage random sequence (32 bit random vector), the random sequence is the generation process of the above-mentioned system information in the randomized Walsh sequence block of the 32 bits in the random sequence of "0 the mapped into [...] "-1 the formed after the [...] a random sequence, the value of the integrity of, for example, as follows: 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1-1 In the implementation of the method for the identification of the mode of transmission of the data before equalization, comprising the steps of: (1) input data arrival in the data frame when the system information, the input data and the data in the memory is multiplied by one by one. (2) transmission 32 after one symbol, the symbol corresponding to the 32 bits of the multiplication result into a 32 bit Walsh transform Walsh transform unit; the Walsh transform on and fast Fourier transform of the same algorithm, the fast Fourier transform of the coefficients in the sign bit, to obtain 32 outputs the result. (3) after Walsh transform of the 32 output result is sent to the comparison device. (4) taking the above-mentioned comparator 32 output in one of the largest absolute value, together with its symbol is sent into the pre-established system information lookup table (system information lookup table content comprises a system information the mode word definition, wherein each in a sequence of "0 the [...] are mapped to a"-1 the [...]), the following is the mode with the above-mentioned system information for example the word corresponding to the definition of the system information of the part of the contents of lookup table comprises: Paragraph 8 vector: 4QAM-NR and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 Paragraph 14 vector: 4QAM and LDPC code rate 3, interleaving mode 2 1 -1 1 1 -1 1 -1 -1 -1 -1 -1 -1 -1 1 -1 -1 1 1 1 -1 -1 -1 1 -1 -1 -1 -1 1 1 -1 -1 1 Section 20 vector: 16QAM and LDPC code rate 3, interleaving mode 2 1 1 -1 1 -1 -1 1 -1 -1 1 1 -1 -1 -1 1 -1 1 -1 -1 -1 -1 1 -1 -1 -1 1 1 1 1 1 1 1 Section 26 vector 32QAM and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 1 -1 -1 -1 1 1 -1 -1 -1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 -1 1 1 -1 1 -1 Through the lookup table to find out the stated 32 the largest absolute value of the output in the corresponding one of the system information, according to the system information matching the transmission mode of the data frame. Adopting the above-mentioned method according to the mode of the system information can be defined accurately identify the word the ground transmission system of the digital television in the transmission mode of the data of each frame. Digital television terrestrial transmission system the receiving end of the method of the present invention for matching the transmission mode, and after the mode of the module such as equalizer and the work of the channel decoding. Implementation of the example two Attached Figure 5 is the total block diagram of the implementation of the method, in the implementation of the method, a length of 32 bits of memory storage random sequence (32 bit random vector), the random sequence is the generation process of the above-mentioned system information in the randomized sequence block Walsh of the 32 bits in the random sequence of "0 the mapped into [...] "-1 the formed after the [...] a random sequence, the integrity of the following values: 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 In the implementation of the method for the identification of the mode of transmission of the data before equalization, comprising the steps of: (1) input data arrival in the data frame when the system information, the input data and the data in the memory is multiplied by one by one. (2) transmission 32 after one symbol, the symbol corresponding to the 32 bits of the multiplication result into a 32 bit Walsh transform Walsh transform unit; for Walsh transform of the 32 × 32 block matrix Walsh of the input 32 bit data forming 32 × 1 column vector multiplication, to obtain 32 after the result output; said 32 × 32 block matrix Walsh of the above-mentioned sending end in the generation of the system information in the course of the 32 × 32 block matrix Walsh of the same ("0 the [...] mapped to"-1 the [...]). (3) after Walsh transform of the 32 output is sent to the comparison device. (4) taking the above-mentioned comparator 32 output in one of the largest absolute value, together with its symbol is sent into the pre-established system information lookup table (system information lookup table content comprises a system information the mode word definition, wherein each in a sequence of "0 the [...] are mapped to a"-1 the [...]), the following is the mode with the above-mentioned system information for example the word corresponding to the definition of the system information of the part of the contents of lookup table comprises: Paragraph 8 vector: 4QAM-NR and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 Paragraph 14 vector: 4QAM and LDPC code rate 3, interleaving mode 2 1 -1 1 1 -1 1 -1 -1 -1 -1 -1 -1 -1 1 -1 -1 1 1 1 -1 -1 -1 1 -1 -1 -1 -1 1 1 -1 -1 1 Section 20 vector: 16QAM and LDPC code rate 3, interleaving mode 2 1 1 -1 1 -1 -1 1 -1 -1 1 1 -1 -1 -1 1 -1 1 -1 -1 -1 -1 1 -1 -1 -1 1 1 1 1 1 1 1 Section 26 vector 32QAM and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 1 -1 -1 -1 1 1 -1 -1 -1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 -1 1 1 -1 1 -1 Through the lookup table to find out the stated 32 the largest absolute value of the output in the corresponding one of the system information, according to the system information matching the transmission mode of the data frame. Adopting the above-mentioned method according to the mode of the system information can be defined accurately identify the word the ground transmission system of the digital television in the transmission mode of the data of each frame. Digital television terrestrial transmission system the receiving end of the method of the present invention for matching the transmission mode, and after the mode of the module such as equalizer and the work of the channel decoding. example three implementation Attached Figure 6 is a shift register (an example is shown in a Figure of the embodiment method of the total block diagram, in the implementation of the method, using a random sequence generating unit to generate 32-bit random sequence, the random sequence generating unit can, for example, includes a 5 bit 3 shown), the shift register 00001 reset to the initial value, the generation polynomial is random sequence G31 (x) = 1 +x+x3 + x4 + x5, its ends need to add a " the 0 [...]. Output, "0 the mapped into [...] "-1 the [...]. 32 bit of the value of the random sequence integrity is as follows: 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 The method of the embodiment in the identification of the mode of transmission of the data before equalization, comprising the steps of: (1) input data arrival of the data frame when the system information, the input data and the random sequence generating unit of the 32 is multiplied by one of random sequence. (2) transmission 32 after one symbol, the symbol corresponding to the 32 bits of the multiplication result into a 32 bit Walsh transform Walsh transform unit; the Walsh transform on and fast Fourier transform of the same algorithm, the fast Fourier transform of the coefficients in the sign bit, to obtain 32 outputs the result. (3) after Walsh transform of the 32 output result is sent to the comparison device. (4) taking the above-mentioned comparator 32 output in one of the largest absolute value, information together with its symbol lookup table into the system (system information lookup table content comprises a system information the mode word definition, wherein, the random in a sequence of "0 the [...] are mapped to a"-1 the [...]), the following is the mode with the above-mentioned system information for example the word corresponding to the definition of the system information of the part of the contents of lookup table comprises: Paragraph 8 vector: 4QAM-NR and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 Paragraph 14 vector: 4QAM and LDPC code rate 3, interleaving mode 2 1 -1 1 1 -1 1 -1 -1 -1 -1 -1 -1 -1 1 -1 -1 1 1 1 -1 -1 -1 1 -1 -1 -1 -1 1 1 -1 -1 1 Section 20 vector: 16QAM and LDPC code rate 3, interleaving mode 2 1 1 -1 1 -1 -1 1 -1 -1 1 1 -1 -1 -1 1 -1 1 -1 -1 -1 -1 1 -1 -1 -1 1 1 1 1 1 1 1 Section 26 vector 32QAM and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 1 -1 -1 -1 1 1 -1 -1 -1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 -1 1 1 -1 1 -1 Through the lookup table to find out the stated 32 the largest absolute value of the output in the corresponding one of the system information, according to the system information matching the transmission mode of the data frame. In the present embodiment, random sequence generating unit for the working process: in random sequence generating unit 7-bit shift register 00001 reset to the initial value, when the input data information when the system, door is opened, the shift register to produce the symbol clock speed of 32 bit random sequence (output "0 the [...] mapped to"-1 the [...]), and multiplied by the input data one by one. This 32 bit random sequence generation process is as follows: 5 the bit shift register 31 generates a symbol clock after PN31 sequence, then the unit re-produce a 0 output (mapped to "-1 the output [...]), and the shift register is reset in the unit, to the initial value 00001. Adopting the above-mentioned method according to the mode of the system information can be defined accurately identify the word the ground transmission system of the digital television in the transmission mode of the data of each frame. Digital television terrestrial transmission system the receiving end of the method of the present invention for matching the transmission mode, and after the mode of the module such as equalizer and the work of the channel decoding. example four implementation Attached Figure 7 is a shift register (for example as shown in Figure of the embodiment method of the total block diagram, in the implementation of the method, using a random sequence generating unit to generate 32-bit random sequence, the random sequence generating unit can include, for example, a 5 bit 3 shown), the shift register 00001 reset to the initial value, the generation polynomial is random sequence G31 (x) = 1 +x+x3 + x4 + x5, its ends need to add a " the 0 [...]. Output, "0 the mapped into [...] "-1 the [...]. 32 bit of the value of the random sequence integrity is as follows: 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1 -1 1 -1 The method of the embodiment in the identification of the mode of transmission of the data before equalization, comprising the steps of: (1) input data arrival of the data frame when the system information, the input data and the random sequence generating unit of the 32 is multiplied by one of random sequence. (2) transmission 32 after one symbol, the symbol corresponding to the 32 bits of the multiplication result into a 32 bit Walsh transform Walsh transform unit; for Walsh transform of the 32 × 32 block matrix Walsh of the input 32 bit data forming 32 × 1 column vector multiplication, to obtain 32 after the result output; said 32 × 32 block matrix Walsh of the above-mentioned sending end in the generation of the system information in the course of the 32 × 32 block matrix Walsh of the same ("0 the [...] mapped to"-1 the [...]). (3) after Walsh transform of the 32 output result is sent to the comparison device. (4) taking the above-mentioned comparator 32 output in one of the largest absolute value, information together with its symbol lookup table into the system (system information lookup table content comprises a system information the mode word definition, wherein, the random in a sequence of "0 the [...] are mapped to a"-1 the [...]), the following is the mode with the above-mentioned system information for example the word corresponding to the definition of the system information of the part of the contents of lookup table comprises: Paragraph 8 vector: 4QAM-NR and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 -1 1 1 1 -1 -1 1 1 -1 1 1 1 1 1 -1 1 -1 -1 -1 1 -1 -1 1 -1 1-1 1 -1 Paragraph 14 vector: 4QAM and LDPC code rate 3, interleaving mode 2 1 -1 1 1 -1 1 -1 -1 -1 -1 -1 -1 -1 1 -1 -1 1 1 1 -1 -1 -1 1 -1 -1 -1 -1 1 1 -1 -1 1 Section 20 vector: 16QAM and LDPC code rate 3, interleaving mode 2 1 1 -1 1 -1 -1 1 -1 -1 1 1 -1 -1 -1 1 -1 1 -1 -1 -1 -1 1 -1 -1 -1 1 1 1 1 1 1 1 Section 26 vector 32QAM and LDPC code rate 3, interleaving mode 2 1 -1 -1 -1 1 -1 -1 -1 1 1 -1 -1 -1 1 1 1 1 1 -1 1 1 1 1 -1 1 1 -1 1 1 -1 1 -1 Through the lookup table to find out the stated 32 the largest absolute value of the output in the corresponding one of the system information, according to the system information matching the transmission mode of the data frame. In the present embodiment, random sequence generating unit for the working process: in random sequence generating unit 7-bit shift register 00001 reset to the initial value, when the input data information when the system, valve is opened, the shift register to produce the symbol clock speed of 32 bit random sequence (output "0 the [...] mapped to"-1 the [...]), and multiplied by the input data one by one. This 32-bit random sequence for the process of:7 bit of the shift register 31 is produced after a symbol clock PN31 sequence, then the unit re-produce a 0 output (mapped to "-1 the output [...]), and the shift register is reset in the unit, to the initial value 00001. Adopting the above-mentioned method according to the mode of the system information can be defined accurately identify the word the ground transmission system of the digital television in the transmission mode of the data of each frame. Digital television terrestrial transmission system the receiving end of the method of the present invention for matching the transmission mode, and after the mode of the module such as equalizer and the work of the channel decoding. The invention relates to a transmission mode distinguishing method suitable for transmission of digital television ground broadcasting, wherein the receiving terminal of the transmission system distinguishes the transmission mode before equalizing the data stream. The method includes: (1) when the received data stream arrives the system information position of data frame, the input data begin to multiply a random sequence of data of n digits one by one, the random sequence of data of n digits has the same generating mode as that of the random sequence used by randomizing Walsh sequence block in the system information generating process; (2) after transmitting n signs, conduct Walsh transformation on the multiplied results of n digits corresponding to these signs; (3) take out the maximum absolute valve from the n output under Walsh transformation, find the corresponding system information based on the mode self-definition of system information during transmission, then match a transmission mode of data frame based on the system information, wherein n is the power of 2. 1. A is applicable to the digital TV terrestrial broadcast transmission method for discriminating the mode of transmission, transmission system comprising in a data frame of a data information representing the system information of the transmission mode, the system information of the n the randomization in the bi-level sequence representation, the n 2 power of, the system information generating process is:n n-n Walsh block contains a Walsh sequence is, this n n bits of a Walsh sequence after taking anti-processing and randomises processing to obtain 2n a system information vector, used for showing the system information, each transmission mode corresponding to the system one of the information vectors, the mode bit definition of the system information of each agreement with the mode of transmission corresponding to the relationship of the system information, the processing to be a n said randomization of n with a n Walsh sequence is multiplied by the random sequence, the stated anti-processing and randomises processing of the sequence may transform, transmission system the receiving end before the equalization processing of the data stream for transmission mode judging, the method comprises the steps of: (1) of the received data flow reaches the system information of the data frame, the input data of n bits with a random sequence data is multiplied by one by one, the n bits of random sequence data and system information generation process of the n bits in the same manner as the generation of the random sequence; (2) after the transmission of n symbols, these symbols is multiplied by n bits corresponding to the Walsh transform result; (3) after taken out of the Walsh transform output n in one of the largest absolute value, information transmission system according to the mode word to find out its corresponding system definition information, then, according to the system information matching the transmission mode of the data frame. 2. Is suitable for the digital television terrestrial broadcasting transmission method for discriminating the transmission mode of the according to Claim 1, characterized in that the system information in the process of generating, Walsh block to the n-order of the randomized for the random sequence n-1 added PN sequence of marked " 0 the generated [...] a random sequence. 3. The is applicable to the digital TV terrestrial broadcasting transmission method for discriminating the transmission mode of the according to Claim 1, characterized in that the step (1) in, the n in the random sequence of "0 the corresponding [...] mapped to"-1 the multiplication of the input data after [...]. 4. Is suitable for the digital television terrestrial broadcasting transmission as in Claim 2 or Claim 3 the transmission mode judging method, is characterized in that n 32, n bit random sequence generating method is as follows: the initial value 00001, according to the generating polynomial G31 (x) = 1 +x+x3 + x4 + x5 generating 31 bit PN sequence, added in its marked " 0 the formed [...] 32 bit random sequence. 5. Is applicable to the digital TV terrestrial broadcast transmission of the transmission mode judging method as in Claim 1 or Claim 3, characterized in that the step (1) in, a memory for storing said n bit random sequence. 6. Is applicable to the digital TV terrestrial broadcast transmission of the transmission mode judging method as in Claim 1 or Claim 3, characterized in that the above-mentioned step (1) in, with a random sequence generating unit to produce said n bit random sequence. 7. Is suitable for the digital television terrestrial broadcasting transmission method for discriminating the transmission mode of the according to Claim 1, characterized in that said step (2) in, with a n-bit Walsh transform Walsh transform unit, the n and n Walsh transform algorithm of the fast Fourier transform FFT algorithm consistent, the Walsh transform FFT transform of the coefficients in the sign bit. 8. Or 7 the is applicable to the digital TV terrestrial broadcasting transmission method for discriminating the transmission mode of the according to Claim 1, characterized in that the step (2) in, with a n-bit Walsh transform unit to perform Walsh transform, n-bit Walsh transform algorithm is completed by the following steps: of the block matrix Walsh n×n for the input of the n n × 1 bit data is multiplied by a column vector, n results obtained. 9. Is suitable for the digital television terrestrial broadcasting transmission method for discriminating the transmission mode of the according to Claim 1, characterized in that the step (3) in, according to the transmission mode of the system information of the word definition to find the corresponding to the method of the system information in: the Walsh transform of the output n in the absolute value of one of the biggest together with its symbol is sent into the pre-established system information lookup table, the lookup table to find the absolute value of the output n in the largest one of the corresponding system information, the system information of the contents of the lookup table system information the definition of the mode word.