Background technology
Digital Television digital broadcasting wireless-related technologies and related industry thereof are that development is very fast in the Communications And Computer field, the industry of good market prospect.The key technology that the anti-interference transmitter transmission technology of digital broadcasting wireless signal is Digital Television digital broadcasting wireless system for whole system performance decisive role, is the object of everybody primary study.Because the develop rapidly of Digital Signal Processing and integrated circuit technique, the system of OFDM (OFDM) technology realizes becoming more and more easier.Because OFDM multi-carrier transmission technology has simple in structure, the availability of frequency spectrum high plurality of advantages such as becomes and extremely everybody concern and obtain deep research and the extensive use in numerous areas such as Xdsl, wide-band mobile communication, wideband wireless local area network, Digital Television digital broadcasting wireless transmitting system in the time of can resisting frequency selectivity and channel.
The higher peak-to-average power ratio (PAPR) of ofdm signal has very high requirement to the range of linearity of amplifier and digital to analog converter, if the system linearity scope can not satisfy the variation of signal, then can cause signal distortion, signal spectrum is changed, thereby cause the orthogonality between the subchannel to be destroyed, produce the phase mutual interference, make system performance degradation.Therefore, the solution that must consider how to reduce the probability of occurrence of big peak power signal in the ofdm signal and reduce the nonlinear distortion influence.
Chnnel coding is the important component part of digital communication system.Under multidiameter fading channel, can be by coding, interweave and the optimal design of modulation scheme reaches big as far as possible signal diversifying exponent number, in order in equaling or exceeding the symbol sebolic addressing of minimum free distance, obtain independent decline.BICM technology (Bit Interleave coded modulation, BitInterleaved Coded Modulation, BICM) adopt bit interleaver and feasible coding and modulated process relatively independent, thereby make and to expand diversity order to different binary bits number from different multi-system symbolic numbers, that is to say that its diversity order L is the smallest hamming distance between the binary code word sequence.Because the BICM technology makes diversity order be improved significantly, therefore, make communication system under multidiameter fading channel, have good bit error performance.
In the practical communication environment, Digital Television digital broadcasting performance in wireless communication systems is subjected to the influence of factors such as lock in time, clock jitter, channel fading, channel disturbance.The anti-interference transmitter transmission method of digital broadcasting wireless signal is the key technology that realizes reliable digit Television Digital broadcast wireless transmissions.
Utilizing Digital Television digital broadcasting wireless transmitting system to provide free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service etc. can control multi-service is the embodiment that Digital Television digital broadcasting wireless transmitting system of new generation satisfies social needs.
Just be based on above background, the present invention is directed to the practical communication environment and propose a kind of digital broadcasting wireless signal anti-jamming transmission method, can satisfy the needs that High Data Rate can be controlled multi-service Digital Television digital broadcasting wireless transmission.
Desire is done more deep understanding to the patent background can be with reference to following documents and materials:
R.V.Nee,R.Prasad.“OFDM?for?wireless?multimedia?communications”.Boston:Artech?House,2000.
Y.Wu,S.Hirakawa,U.H.Reimers,and?J.Whitaker.“Overview?of?digital?television?development,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.8-21,Jan.2006.
U.Ladebusch?and?C.A.Liss.“Terrestrial?DVB(DVB-T)A?broadcast?technology?for?stationary?portable?and?mobile?use,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.183-194,Jan.2006.
M.Takada?and?M.Saito.“Transmission?systems?for?ISDB-T,”Proceedings?of?the?IEEE,Special?Issue?on?Global?Digital?Television:Technology?and?Emerging?Services,pp.251-256,Jan.2006.
G.Caire,G.Taricco,E.Biglieri,“Bit-interleaved?coded?modulation,”IEEE?Trans.Information?Theory,vol.44,no.3,pp.927-946,May?1998.
Summary of the invention
The present invention is directed to High Data Rate and can control multi-service Digital Television digital broadcasting wireless transmission problem, proposed a kind of digital broadcasting wireless signal anti-jamming transmission method.
A kind of digital broadcasting wireless signal anti-jamming transmission method that the present invention proposes is characterized in that it comprises the following steps:
1) the anti-interference transmitter of digital broadcasting wireless signal converts the multi-medium data media data processor of flowing through to bit stream, and the scrambler sequence of utilizing feedback shift register to produce is carried out scrambling and handled to form the input data bit flow;
2) the anti-interference transmitter of digital broadcasting wireless signal is flowed through the input data bit of oneself and is formed FFT Bit Interleave coding modulation data piece at frequency domain after multi code Rate of Chinese character is deleted surplus convolutional encoding, Bit Interleave, code element modulation, FFT represents the fast discrete Fourier conversion, and the length of FFT Bit Interleave coding modulation data piece is K;
3) the anti-interference transmitter of digital broadcasting wireless signal adopts IFFT that FFT Bit Interleave coding modulation data piece is transformed to time domain discrete Bit Interleave coding modulation data sample value piece D
Total, IFFT represents the fast discrete Fourier inverse transformation;
4) the anti-interference transmitter of digital broadcasting wireless signal is divided equally into two with time domain discrete Bit Interleave coding modulation data sample value piece in order, the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1With the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
2, D
Total=[D
1, D
2];
5) the anti-interference transmitter of digital broadcasting wireless signal passes through the peak-to-average power ratio adjustment unit to the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1, the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
2Carry out that signal adds, subtracts, conjugate operation is handled and synthetic new time domain discrete Bit Interleave coding modulation data sample value piece D again
New, new time domain discrete Bit Interleave coding modulation data sample value piece D
NewAdopt following generate pattern to obtain, generate pattern 1 is D
New=[D
1, D
2], generate pattern 2 is
Generate pattern 3 is
Generate pattern 4 is
Generate pattern 5 is
Generate pattern 6 is
Generate pattern 7 is D
New=[D
* 1, D
2], generate pattern 8 is
Generate pattern 9 is
Generate pattern 10 is
Generate pattern 11 is
Generate pattern 12 is
Compare the synthetic time domain discrete Bit Interleave coding modulation data sample value piece D of 12 kinds of generate patterns
New, choose wherein have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece falls
And peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece will fall
The corresponding generate pattern information that adopts send to the operational indicator sequence unit be set, wherein, D
* 1Expression is to the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1Each time domain discrete Bit Interleave coding modulation data sample value carry out that conjugate operation is handled and the sub-piece of time domain discrete Bit Interleave coding modulation data sample value that obtains;
6) the anti-interference transmitter of digital broadcasting wireless signal inserts Cyclic Prefix at interval as protection and falls peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece, peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece falls in formation, as frame, the length of Cyclic Prefix is C, and the length of falling peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece is C+K;
7) the anti-interference transmitter of digital broadcasting wireless signal with training sequence as the real part sequence of sequence of plural training, the operational indicator sequence is arranged the set operational indicator sequence in unit as the imaginary part sequence of sequence of plural training, constitute the discrete sample block of sequence of plural training in time domain, the length of the discrete sample block of training sequence, operational indicator sequence, sequence of plural training all is X, and the operational indicator sequence is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal;
8) discrete sample block of the anti-interference transmitter of the digital broadcasting wireless signal sequence of plural training that will constitute in time domain repeats 2 times continuously and forms time domain repetition training series of discrete sample value piece on time domain, as frame head;
9) the anti-interference transmitter of digital broadcasting wireless signal is that frame head is inserted into that to fall peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece be frame with time domain repetition training series of discrete sample value piece, to form signal frame;
10) the anti-interference transmitter of digital broadcasting wireless signal adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
11) the anti-interference transmitter of digital broadcasting wireless signal forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave;
12) radiofrequency signal that sends of the anti-interference transmitter of digital broadcasting wireless signal anti-interference reception machine testing receiving digital broadcast wireless signal and its down-conversion formed baseband signal is utilized the architectural characteristic of the Cyclic Prefix characteristic of signal frame and signal frame to carry out baseband signal and is received and handle.
Digital broadcasting wireless signal anti-jamming transmission method according to above-mentioned is characterized in that: the anti-interference transmitter of digital broadcasting wireless signal fall peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece by the signal that the sub-piece of time domain discrete Bit Interleave coding modulation data sample value is undertaken by specific 12 kinds of generate patterns add, subtract, conjugate operation is handled and synthetic again; Has periodic time domain repetition training series of discrete sample value piece in the signal frame of the anti-interference transmitter of digital broadcasting wireless signal; The length X of the training sequence of the anti-interference transmitter of digital broadcasting wireless signal is in 512,1024,2048, the length K of corresponding FFT Bit Interleave coding modulation data piece is respectively 2048,4096,8192, the frequency interval of corresponding subcarrier is respectively 4KHz, 2KHz, 1KHz, and corresponding circulating prefix-length C is respectively 1/4,1/8,1/16 of FFT Bit Interleave coding modulation data block length K size; The training sequence of the anti-interference transmitter of digital broadcasting wireless signal, operational indicator sequence are formed by a series of 1 or-1, have pseudo-random characteristics; Training sequence, the operational indicator sequence of the anti-interference transmitter of digital broadcasting wireless signal have orthogonality each other; Each different operational indicator sequence of the anti-interference transmitter of digital broadcasting wireless signal is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal; The input data are carried out multi code Rate of Chinese character, and to delete the encoding rate of surplus convolutional encoding be in 1/4,1/2,5/8,3/4 and 7/8 one; Bit Interleave adopts the random interleaving mode; Code element is modulated to a kind of among QPSK, 16QAM, 32QAM and the 64QAM, and symbol constellations figure mapping mode adopts the Gray code mapping.Digital broadcasting wireless signal antijam receiver can take full advantage of the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame is carried out baseband signal reception processing, handles comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
Characteristics of the present invention:
The present invention is the transmission plan that a kind of time-domain and frequency-domain mixes.Generate pattern of falling peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece of the present invention and have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece choosing method falls, but the very high big peak power signal probability of the maximum peak power that not only can take full advantage of ofdm signal is very low, the real part (or imaginary part) of the ofdm signal when number of sub carrier wave is big is the characteristic of multiple Gaussian random process and whose amplitude obeys Rayleigh distribution, the amount of information of the required extra transmission of adopting of generate pattern is little, be easy to handle the primary signal of recovering to obtain ofdm signal at receiver end, the orthogonal property that can not destroy sub-carrier signal simultaneously can not produce extra nonlinear distortion yet.Has periodic time domain repetition training series of discrete sample value piece in the signal frame of the anti-interference transmitter of digital broadcasting wireless signal, the training sequence of the anti-interference transmitter of digital broadcasting wireless signal, the operational indicator sequence has pseudo-random characteristics, the training sequence of the anti-interference transmitter of digital broadcasting wireless signal, the operational indicator sequence has orthogonality each other, the signal frame of the anti-interference transmitter of digital broadcasting wireless signal is that frame head is inserted into that to fall peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece be frame and forming by time domain repetition training series of discrete sample value piece, and these have guaranteed that digital broadcasting wireless signal antijam receiver can realize frame synchronization fast and accurately, Frequency Synchronization, time synchronized, channel transfer characteristic is estimated, and phase noise and channel transfer characteristic reliably followed the tracks of.Cyclic Prefix is fallen peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece to form signal frame body as the insertion of protection interval, can reduce the interference effect between signal frame head and the frame Bit Interleave coding modulation data.Adopt BICM that the input data are carried out the Bit Interleave coded modulation and improved diversity order, make communication system under multidiameter fading channel, have good bit error performance.Each different operational indicator sequence of the anti-interference transmitter of digital broadcasting wireless signal is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal, Digital Television digital broadcasting wireless transmitting system can satisfy social needs so that can provide free television broadcasting, paid television broadcasting, security information transmission, multimedia value-added service etc. can control multi-service.Transmission method of the present invention has the equal power ratio of ebb, lock in time is short, clock jitter is little, anti-channel fading, anti-channel disturbance, can provide higher bit interweaving encoding modulation data rate can control plurality of advantages such as multi-service Digital Television digital broadcasting wireless transmission.
Embodiment
Below in conjunction with accompanying drawing specific embodiments of the invention are described in detail.
The embodiment schematic diagram of signal transmission between certain transmitter and receiver of the digital broadcasting wireless signal anti-jamming transmission method that proposes according to the present invention as shown in Figure 1, follows these steps to carry out:
1) the anti-interference transmitter of this certain digital broadcasting wireless signal converts the multi-medium data media data processor of flowing through to bit stream, and the scrambler sequence of utilizing feedback shift register to produce is carried out scrambling and handled to form the input data bit flow;
2) the anti-interference transmitter of this certain digital broadcasting wireless signal is flowed through the input data bit of oneself and is formed FFT Bit Interleave coding modulation data piece at frequency domain after multi code Rate of Chinese character is deleted surplus convolutional encoding, Bit Interleave, code element modulation, FFT represents the fast discrete Fourier conversion, and the length of FFT Bit Interleave coding modulation data piece is K; The input data are carried out multi code Rate of Chinese character deletes the multi code Rate of Chinese character of surplus convolutional encoding, Bit Interleave, code element modulation treatment to delete the encoding rate of surplus convolutional encoding is in 1/4,1/2,5/8,3/4 and 7/8 one, Bit Interleave adopts the random interleaving mode, code element is modulated to a kind of among QPSK, 16QAM, 32QAM and the 64QAM, and symbol constellations figure mapping mode adopts the Gray code mapping;
3) the anti-interference transmitter of this certain digital broadcasting wireless signal adopts IFFT that FFT Bit Interleave coding modulation data piece is transformed to time domain discrete Bit Interleave coding modulation data sample value piece D
Total, IFFT represents the fast discrete Fourier inverse transformation;
4) the anti-interference transmitter of this certain digital broadcasting wireless signal is divided equally into two with time domain discrete Bit Interleave coding modulation data sample value piece in order, the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1With the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
2, D
Total=[D
1, D
2];
5) the anti-interference transmitter of this certain digital broadcasting wireless signal passes through the peak-to-average power ratio adjustment unit to the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1, the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
2Carry out that signal adds, subtracts, conjugate operation is handled and synthetic new time domain discrete Bit Interleave coding modulation data sample value piece D again
New, new time domain discrete Bit Interleave coding modulation data sample value piece D
NewAdopt following generate pattern to obtain, generate pattern 1 is D
New=[D
1, D
2], generate pattern 2 is
Generate pattern 3 is
Generate pattern 4 is
Generate pattern 5 is
Generate pattern 6 is
Generate pattern 7 is D
New=[D
* 1, D
2], generate pattern 8 is
Generate pattern 9 is
Generate pattern 10 is
Generate pattern 11 is
Generate pattern 12 is
Compare the synthetic time domain discrete Bit Interleave coding modulation data sample value piece D of 12 kinds of generate patterns
New, choose wherein have a minimum peak-to-average power ratio peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece falls
And peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece will fall
The corresponding generate pattern information that adopts send to the operational indicator sequence unit be set, wherein, D
* 1Expression is to the sub-piece D of time domain discrete Bit Interleave coding modulation data sample value
1Each time domain discrete Bit Interleave coding modulation data sample value carry out that conjugate operation is handled and the sub-piece of time domain discrete Bit Interleave coding modulation data sample value that obtains;
6) the anti-interference transmitter of digital broadcasting wireless signal inserts Cyclic Prefix at interval as protection and falls peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece, peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece falls in formation, as frame, the length of Cyclic Prefix is C, and the length of falling peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece is C+K;
7) the anti-interference transmitter of digital broadcasting wireless signal is with the real part sequence of training sequence as sequence of plural training, the operational indicator sequence is arranged the set operational indicator sequence in unit as the imaginary part sequence of sequence of plural training, constitute the discrete sample block of sequence of plural training in time domain, training sequence, the operational indicator sequence, the length of the discrete sample block of sequence of plural training all is X, the operational indicator sequence is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal, and X gets 512,1024, in 2048 one; When X got 512, K got 2048, C and gets 1/4 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 4KHz; When X got 1024, K got 4096, C and gets 1/8 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 2KHz; When X got 2048, K got 8192, C and gets 1/16 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 1KHz;
8) discrete sample block of the anti-interference transmitter of the digital broadcasting wireless signal sequence of plural training that will constitute in time domain repeats 2 times continuously and forms time domain repetition training series of discrete sample value piece on time domain, as frame head;
9) the anti-interference transmitter of digital broadcasting wireless signal is that frame head is inserted into that to fall peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece be frame with time domain repetition training series of discrete sample value piece, to form signal frame;
10) the anti-interference transmitter of this certain digital broadcasting wireless signal adopts square root raised cosine filter that the signal pulse of signal frame is shaped;
11) the anti-interference transmitter of this certain digital broadcasting wireless signal forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave;
12) radiofrequency signal that sends of the anti-interference transmitter of this certain digital broadcasting wireless signal anti-interference reception machine testing receiving digital broadcast wireless signal and its down-conversion formed baseband signal, utilize the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame to carry out baseband signal reception processing, handle comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
According to the embodiment schematic diagram that signal frame in the signals transmission between certain transmitter and receiver of digital broadcasting wireless signal anti-jamming transmission method of the present invention forms, as shown in Figure 2, specifically implement as follows:
The anti-interference transmitter of this certain digital broadcasting wireless signal converts the multi-medium data media data processor of flowing through to bit stream, and the scrambler sequence of utilizing feedback shift register to produce is carried out scrambling and handled to form the input data bit flow.
The anti-interference transmitter of this certain digital broadcasting wireless signal is deleted surplus convolutional encoding with the input data bit of oneself multi code Rate of Chinese character of flowing through, Bit Interleave, code element modulation back forms FFT Bit Interleave coding modulation data piece at frequency domain, the length of FFT Bit Interleave coding modulation data piece is K, FFT Bit Interleave coding modulation data piece is made up of subcarrier, through IFFT it is transformed to the discrete bits interweaving encoding modulating data sample value piece of time domain again, generates by the peak-to-average power ratio adjustment unit and choose the peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece that falls that wherein has minimum peak-to-average power ratio and simultaneously the generate pattern information of the corresponding employing of institute is sent to the operational indicator sequence unit is set.The input data are carried out multi code Rate of Chinese character deletes the multi code Rate of Chinese character of surplus convolutional encoding, Bit Interleave, code element modulation treatment to delete the encoding rate of surplus convolutional encoding is in 1/4,1/2,5/8,3/4 and 7/8 one, Bit Interleave adopts the random interleaving mode, code element is modulated to a kind of among QPSK, 16QAM, 32QAM and the 64QAM, and symbol constellations figure mapping mode adopts the Gray code mapping.
The anti-interference transmitter of this certain digital broadcasting wireless signal inserts Cyclic Prefix at interval as protection and falls peak-to-average power ratio time domain discrete Bit Interleave coding modulation data sample value piece; peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece falls in formation; as frame, the length of Cyclic Prefix is C.
The anti-interference transmitter of this certain digital broadcasting wireless signal with training sequence as the real part sequence of sequence of plural training, the operational indicator sequence is arranged the set operational indicator sequence in unit as the imaginary part sequence of sequence of plural training, constitute the discrete sample block of sequence of plural training in time domain, the length of the discrete sample block of training sequence, operational indicator sequence, sequence of plural training all is X, and the operational indicator sequence is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal.
The discrete sample block of the sequence of plural training that the anti-interference transmitter of this certain digital broadcasting wireless signal will constitute in time domain repeats 2 times continuously and forms time domain repetition training series of discrete sample value piece on time domain, as frame head.
The anti-interference transmitter of this certain digital broadcasting wireless signal is that frame head is inserted into that to fall peak-to-average power ratio time domain cyclic prefix discrete bits interweaving encoding modulating data sample value piece be frame with time domain repetition training series of discrete sample value piece, to form signal frame.
The anti-interference transmitter of this certain digital broadcasting wireless signal adopts square root raised cosine filter that the signal pulse of signal frame is shaped.
The X of the anti-interference transmitter of this certain digital broadcasting wireless signal gets in 512,1024,2048; When X got 512, K got 2048, C and gets 1/4 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 4KHz; When X got 1024, K got 4096, C and gets 1/8 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 2KHz; When X got 2048, K got 8192, C and gets 1/16 of K size, and the frequency interval of FFT Bit Interleave coding modulation data piece subcarrier is got 1KHz; Training sequence, operational indicator sequence as the anti-interference transmitter of digital broadcasting wireless signal are formed by a series of 1 or-1, have pseudo-random characteristics, and training sequence, operational indicator sequence have orthogonality each other.The training sequence that satisfies above-mentioned feature can be by realizing as one group of displacement m sequence of a kind of specific type of pseudo-random number sequence with as the walsh sequence of orthogonal sequence, Hadamard sequences or by the orthogonal sequence that other modes produce.Each different operational indicator sequence is comprising and unique each system parameters and business model information of expressing the anti-interference transmitter of digital broadcasting wireless signal.When X got 512, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.1; When X got 1024, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.05; When X got 2048, the corresponding signal to signal frame carried out the rolloff-factor of the square root raised cosine filter of pulse shaping and gets 0.025.
The anti-interference transmitter of this certain digital broadcasting wireless signal forms emission of radio frequency signals to the on-air radio channel with the baseband signal up-conversion to carrier wave.
The radiofrequency signal that the anti-interference transmitter of this certain digital broadcasting wireless signal anti-interference reception machine testing receiving digital broadcast wireless signal sends also forms baseband signal with its down-conversion, utilize the Cyclic Prefix characteristic of signal frame and the architectural characteristic of signal frame to carry out baseband signal reception processing, handle comprising the time domain and frequency domain combined alternate analysis to signal frame head and signal frame body.
By reference to the accompanying drawings specific embodiments of the invention are had been described in detail above, but the present invention is not limited to above-described embodiment, under the spirit and scope situation of the claim that does not break away from the application, those skilled in the art can make various modifications or remodeling.