CN106330615A - Ground digital broadcasting television signal physical layer bandwidth determining method based on occupied bandwidth measurement - Google Patents

Abstract

The invention provides a ground digital broadcasting television signal physical layer bandwidth determining method based on occupied bandwidth measurement. Bandwidths of two sides of central frequency of 99% power proportion almost comprise a signal main lobe width according to a result of a simulation experiment, and therefore the above mentioned method is firstly used for sampling ground digital broadcasting television signal base band time domain signals. Ground digital broadcasting television signal base band time domain sampling data is converted into frequency domain data to calculate 0.8Bw bandwidth total power. The 99% power proportion bandwidth is calculated in two phases, and in the first phase, rough positions of 0.5% power proportions of a left side and a right side of interval segments are quickly and effectively positioned, and in the second phase, accurate positioning in the intervals is carried out to find the starting position and the end position of the proportion bandwidth. The physical layer bandwidth mode of the ground digital broadcasting television signal is determined according to a measured bandwidth value.

Description

The received terrestrial digital broadcasting TV signal physical layer bandwidth measured based on occupied bandwidth judges Method

Technical field

The present invention relates to digital broadcasting divisions, have multiple physical layers bandwidth for received terrestrial digital broadcasting TV signal, propose A kind of received terrestrial digital broadcasting TV signal physical layer bandwidth decision method measured based on occupied bandwidth.

Background technology

Digital processing technology obtains success, phase greatly along with the high speed development of computer technology with image processing techniques Compared with simulated television, DTV can provide more preferable program quality and more preferably audiovisual experience for consumer.Typically, ground number Word broadcast television signal physical layer bandwidth has different patterns.If ground digital television broadcast (DVB) standard is the most in the world Most widely used general, digital television transfer standard that technology is the most ripe, have employed the OFDM modulation (C-of chnnel coding OFDM) technology.The basic cycle T of DVB-T signal, corresponding sample frequency is 1/T, for 8MHz channel basic cycle T is 7/64 μ s, is 1/8 μ s for 7MHz channel T, is 7/48 μ s for 6MHz channel T, is 7/40 μ s for 5MHz channel T.China CMMB (CMMB) physical layer bandwidth includes 8MHz and 2MHz.And signal energy has focused largely on main lobe, with As a example by 8MHz channel DVB-T signal, its preferable frequency spectrum main lobe is roomy is about 7.61MHz.

For digital demodulator, the problem that receiving terminal first has to solve is whether just to obtain with the sample rate of regulation True sampled signal, the most just can carry out correct demodulation.Nowadays at most digital television signal frequency spectrum detection instrument In, need manually to arrange the bandwidth chahnel of measured signal parameter, the physical layer band of the received terrestrial digital broadcasting TV signal i.e. received Width, this also means that the digital broadcasting-television signal physical layer bandwidth of transmission need to be known.This adds to user undoubtedly and makes Use difficulty.Simultaneously for portable signal detecting instrument, it is the most tired comparatively speaking that the continuous high-resolution of sample rate to be realized is adjustable Difficult.

Chinese invention patent application is open says that (CN 102724000 A) is in " taking disclosed in 10 days October in 2012 Bandwidth test system and method " step is used calculating occupied bandwidth divide bigness scale examination and accurate measurement to try two steps, wherein and by test Frequency range segmentation, can adjust for occupied bandwidth bigness scale examination and the parameter of accurate measurement examination, the party according to described power and described frequency Method Shortcomings:

The method does not accounts in field of digital signals, and Frequency point is discrete, can exist non-whole at start-stop Frequency point The what state of several points more accurately obtains performance number.

Summary of the invention

It is an object of the invention to find a kind of physical layer bandwidth quickly and easily judging received terrestrial digital broadcasting TV signal Decision method, it is provided that a kind of received terrestrial digital broadcasting TV signal physical layer bandwidth decision method measured based on occupied bandwidth.

For achieving the above object, the invention provides a kind of received terrestrial digital broadcasting TV signal measured based on occupied bandwidth Physical layer bandwidth decision method, the method utilizes occupied bandwidth to measure the interval shared by fast searching spectrum signal main lobe, thus Achieve the differentiation of its transmitting physical layer bandwidth.

The present invention includes the sampling to ground digital broadcast television base band time domain data, it is characterised in that include following step Rapid:

1, a kind of received terrestrial digital broadcasting TV signal physical layer bandwidth decision method, it is characterised in that comprise the following steps:

Step 1, the received terrestrial digital broadcasting TV signal base band time domain signal that total time span is T is done sample frequency is f_sSampling, obtaining frequency range is B_w, data volume be N_allReceived terrestrial digital broadcasting TV signal base band time domain sampled data r, wherein N_allFor received terrestrial digital broadcasting TV signal base band time domain samples sum；

Step 2, the base band time domain sampled data r obtaining step 1 carries out windowing and fast discrete Fourier transformation processes Become frequency domain data X；

Step 2.1, chooses window function and base band time domain sampled data r is carried out windowing process, and the formula in this step is as follows:

X (n)=r (n) w (n)

Wherein:

W (n) represents the window function value of nth point；

R (n) represents the base band time domain samples of nth point；

X (n) represents the base band time domain data sample value after nth point windowing；

Step 2.2, makees the conversion of fast discrete Fourier transformation to the base band time domain data sample value after windowing by the circulation of step-length K For frequency domain data X, the formula in this step is as follows:

$X\left(k\right)=\underset{n=0}{\overset{K-1}{\Σ}}x\left(n\right)e^{-j\frac{2\mathrm{\π}}{K}nk}$

Wherein:

X (n) represents the base band time domain data sample value after nth point windowing；

X (k) represents kth point frequency domain data sample value；

J represents imaginary unit；

K represents step-length；

N represents base band time domain data sequence number；

K represents frequency domain data sequence number；

π represents pi；

Step 3, signal calculated mid frequency both sides 0.8B altogether_wThe total power signal of bandwidth；

Step 3.1, takes bandwidth B altogether in signal transmission center frequency values both sides in frequency domain data X_wFrequency domain data be designated as X₁, calculate Mid frequency both sides bandwidth 0.8B_wOriginal position d of frequency domain data₁With final position d₂, original position d₁With final position d₂'s Computing formula is as follows:

$X\left(d_1\right)=\[X(\stackrel{\‾}{d_1}+1)-X\left(\stackrel{\‾}{d_1}\right)\]\[d_1-\stackrel{\‾}{d_1}\]+X\left(\stackrel{\‾}{d_1}\right)$

$X\left(d_2\right)=\[X(\stackrel{\‾}{d_2}+1)-X\left(\stackrel{\‾}{d_2}\right)\]\[d_2-\stackrel{\‾}{d_2}\]+X\left(\stackrel{\‾}{d_2}\right)$

Wherein:

Represent d respectively₁With d₂Round downwards；

X(d₁) represent in original position d₁The frequency domain data at place estimates sample value；

X(d₂) represent at final position d₂The frequency domain data at place estimates sample value；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Step 3.2, calculates original position d₁With final position d₂Between general power P of frequency-region signal_sum, its formula is as follows:

$P_{sum}=10\log \[\frac{Ch\×{\mathrm{Ph}}^2\×Enbw\×S}{mRBW\×{\mathrm{Eh}}^2(\stackrel{\‾}{d_2}-\stackrel{\‾}{d_1})}\]$

$S=\underset{i=d_1}{\overset{d_2}{\Σ}}\left|X\left(i\right)\right|$

Wherein:

Ch represents bandwidth 0.8B_w；

MRBW represents resolution bandwidth；

Ph represents power gain value；

Eh represents calculating yield value；

Enbw represents window yield value；

Represent d respectively₁With d₂Round downwards；

P_sumRepresent 0.8B_wBandwidth signal general power；

S represents frequency domain data amplitude sum between start-stop position；

X (i) represents the frequency domain data sample value of i-th；

Step 4, calculates and accounts for general power P_sumThe midbandwidth of 99%；

Step 4.1, calculates and accounts for general power P_sumThreshold value P of 0.5%_limit, its formula is:

$P_{\lim it}=10log({10}^{P_{sum}/10}\×0.5\%)$

Wherein:

P_sumRepresent 0.8B_wBandwidth signal general power；

P_limitRepresent and account for general power P_sumThe threshold value of 0.5%；

Step 4.2, at frequency domain data X₁Interior original position d₁With final position d₂In the range of, location left and right side merit respectively Rate is threshold value P_limitApproximate location interval, specific practice is: step-length K is divided into D group, respectively from left side with original position d₁ Start to the right, right side is with final position d₂Start the most successively by group accumulation calculating performance number P, when performance number P is first more than door Limit value P_limitTime, the class interval that record is added to, i.e. position P_LeftWith P_RightSubstantially place is interval, is designated as greatly in these two intervals Cause interval A₁With A₂；Described P_LeftWith P_RightRepresent respectively and account for general power P_sumThe bandwidth of 99% start stop bit on frequency domain point Put；

Step 4.3, calculates the most successively from left side original position d₁To the right to substantially interval A₁Position one by one, right side eventually Stop bit puts d₂To the left to substantially interval A₂Performance number P of position one by one, find performance number P for the first time more than threshold value P_limit's Position P_LeftWith P_Right, i.e. interval Z=[P_Left,P_Right] internal power accounts for general power P_sum99%, its conversion bandwidth length BW As follows:

BW=(P_Right-P_Left)f_s/K

Wherein:

P_LeftWith P_RightRepresent and account for general power P_sumThe bandwidth of 99% start-stop position on frequency domain point；

f_sRepresent sample frequency；

K represents fast discrete Fourier transformation step-length；

Step 5, the threshold value that the physical layer bandwidth of terrestrial digital broadcasting signal judges is respectively BW₁、BW₂、BW₃And BW₄, (0, BW₁]、(BW₁,BW₂]、(BW₂,BW₃]、(BW₃,BW₄] and (BW₄,+∞) respectively corresponding 2MHz channel, 5MHz channel, 6MHz channel, The judgement of 7MHz channel and 8MHz channel is interval, and the interval that BW is positioned at can obtain the transmission signal physical layer bandwidth mould of correspondence Formula.

Preferably for terrestrial digital broadcasting signal, time-domain signal time span T described in step 1 takes 1ms.

Preferably, the K value described in step 3 is 4096.

Preferably, the D value described in step 4 is 20.

Preferably, the BW described in step 5₁、BW₂、BW₃And BW₄Respectively value be 3.148MHz, 5.2335MHz, 6.185MHz and 7.135MHz.

Preferably, the received terrestrial digital broadcasting TV signal base band time domain signal described in step 1 is DVB-T base band time domain letter Number.

Compared with prior art, the invention has the beneficial effects as follows: provide a kind of ground number measured based on occupied bandwidth Word broadcast singal physical layer bandwidth method, the characteristic of the digital field discrete signal taken into full account, simultaneously to different physical layer bands Terrestrial digital broadcasting signal time domain data under Kuan, all has only to sampling with the most relatively high sampling rate 12.5MHz, then Repeatable utilize these data to make the conversion of down-sampled rate to be changed into the terrestrial digital broadcasting signal time-domain signal of standard sample rate, and The method is simple and quick to be easily achieved.

Accompanying drawing explanation

Fig. 1 is basic skills schematic flow sheet of the present invention；

Fig. 2 is the power spectrum chart of DVB-T signal 5MHz channelling mode occupied bandwidth test；

Fig. 3 is the power spectrum chart of DVB-T signal 6MHz channelling mode occupied bandwidth test；

Fig. 4 is the power spectrum chart of DVB-T signal 7MHz channelling mode occupied bandwidth test；

Fig. 5 is the power spectrum chart of DVB-T signal 8MHz channelling mode occupied bandwidth test；

Fig. 6 is that the DVB-T signal utilizing the embodiment of the present invention finally demodulates planisphere；

Detailed description of the invention

Below in conjunction with the accompanying drawings embodiments of the invention are described in further detail.

In an embodiment, the input signal chosen is DVB-T base band time domain signal；DVB-T base band time domain signal is sampled Time sample frequency f_sTake 12.5MHz, signal frequency range B_wFor 12.5MHz；DVB-T time-domain signal time span T takes 1ms.

Fig. 1 is basic skills schematic flow sheet of the present invention.It may be seen that the invention mainly includes steps:

Step 1, the DVB-T base band time domain signal that total time span is 1ms is done sample frequency is adopting of 12.5MHz Sample, obtaining frequency range is B_w, data volume be N_allDVB-T base band time domain sampled data r, wherein N_allFor DVB-T base band time domain sample Value sum.

Step 2, the DVB-T base band time domain sampled data r obtaining step 1 carries out windowing and fast discrete Fourier transformation Process becomes frequency domain data X.

Step 2.1, chooses window function and DVB-T base band time domain data r is carried out windowing process, and the formula in this step is such as Under:

X (n)=r (n) w (n)

Wherein:

W (n) represents the window function value of nth point；

R (n) represents the base band time domain samples of nth point；

X (n) represents the base band time domain data sample value after nth point windowing；

Step 2.2, makees the conversion of fast discrete Fourier transformation to the base band time domain data sample value after windowing by the circulation of step-length K For frequency domain data X, K takes 4096 in the present embodiment, and the formula in this step is as follows:

$X\left(k\right)=\underset{n=0}{\overset{K-1}{\Σ}}x\left(n\right)e^{-j\frac{2\mathrm{\π}}{K}nk}$

Wherein:

X (n) represents the base band time domain data sample value after nth point windowing；

X (k) represents kth point frequency domain data sample value；

J represents imaginary unit；

K represents step-length；

N represents base band time domain data sequence number；

K represents frequency domain data sequence number；

π represents pi.

Step 3, signal calculated mid frequency both sides 0.8B altogether_wThe total power signal of bandwidth.

Step 3.1, takes bandwidth B altogether in signal transmission center frequency values both sides in frequency domain data X_wFrequency domain data be designated as X₁, calculate Mid frequency both sides bandwidth 0.8B_wOriginal position d of frequency domain data₁With final position d₂, original position d₁With final position d₂'s Computing formula is as follows:

$X\left(d_1\right)=\[X(\stackrel{\‾}{d_1}+1)-X\left(\stackrel{\‾}{d_1}\right)\]\[d_1-\stackrel{\‾}{d_1}\]+X\left(\stackrel{\‾}{d_1}\right)$

$X\left(d_2\right)=\[X(\stackrel{\‾}{d_2}+1)-X\left(\stackrel{\‾}{d_2}\right)\]\[d_2-\stackrel{\‾}{d_2}\]+X\left(\stackrel{\‾}{d_2}\right)$

Wherein:

Represent d respectively₁With d₂Round downwards；

X(d₁) represent in original position d₁The frequency domain data at place estimates sample value；

X(d₂) represent at final position d₂The frequency domain data at place estimates sample value；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Step 3.2, calculates the general power of signal between start-stop position, and its formula is as follows:

$P_{sum}=10\log \[\frac{Ch\×{\mathrm{Ph}}^2\×Enbw\×S}{mRBW\×{\mathrm{Eh}}^2(\stackrel{\‾}{d_2}-\stackrel{\‾}{d_1})}\]$

$S=\underset{i=d_1}{\overset{d_2}{\Σ}}\left|X\left(i\right)\right|$

Wherein:

Ch represents bandwidth 0.8B_w；

MRBW represents resolution bandwidth；

Ph represents power gain value；

Eh represents calculating yield value；

Enbw represents window yield value；

P_sumRepresent 0.8B_wBandwidth signal general power；

S represents frequency domain data amplitude sum between start-stop position；

X (i) represents the frequency domain data sample value of i-th.

Step 4, calculates and accounts for general power P_sumThe midbandwidth of 99%.

Step 4.1, calculates and accounts for general power P_sumThreshold value P of 0.5%_limit, its formula is:

$P_{\lim it}=10log({10}^{P_{sum}/10}\×0.5\%)$

Wherein:

P_sumRepresent 0.8B_wBandwidth signal general power；

P_limitRepresent and account for general power P_sumThe threshold value of 0.5%；

Step 4.2, at frequency domain data X₁Interior original position d₁With final position d₂In the range of, location left and right side merit respectively Rate is threshold value P_limitApproximate location interval, specific practice is: step-length K is divided into 20 groups, respectively from left side with original position d₁Start to the right, right side is with final position d₂Start the most successively by group accumulation calculating performance number P, when performance number P is first more than door Limit value P_limitTime, the class interval that record is added to, i.e. position P_LeftWith P_RightSubstantially place is interval, is designated as greatly in these two intervals Cause interval A₁With A₂；Described P_LeftWith P_RightRepresent respectively and account for general power P_sumThe bandwidth of 99% start stop bit on frequency domain point Put；

Step 4.3, calculates the most successively from left side original position d₁To the right to substantially interval A₁Position one by one, right side eventually Stop bit puts d₂To the left to substantially interval A₂Performance number P of position one by one, find performance number P for the first time more than threshold value P_limit's Position P_LeftWith P_Right, i.e. interval Z=[P_Left,P_Right] internal power accounts for general power P_sum99%, its conversion bandwidth length BW As follows:

BW=(P_Right-P_Left)f_s/K

Wherein:

P_LeftWith P_RightRepresent and account for general power P_sumThe bandwidth of 99% start-stop position on frequency domain point；

f_sRepresent sample frequency；

K represents fast discrete Fourier transformation step-length.

Step 5, the threshold value that the physical layer bandwidth of terrestrial digital broadcasting signal judges is respectively BW₁、BW₂、BW₃And BW₄, (0, BW₁]、(BW₁,BW₂]、(BW₂,BW₃]、(BW₃,BW₄] and (BW₄,+∞) respectively corresponding 2MHz channel, 5MHz channel, 6MHz channel, The judgement of 7MHz channel and 8MHz channel is interval, and the interval that BW is positioned at can obtain the transmission signal physical layer bandwidth mould of correspondence Formula, in the present embodiment, BW₁、BW₂、BW₃And BW₄Respectively value be 3.148MHz, 5.2335MHz, 6.185MHz and 7.135MHz。

For verifying the implementation result of the inventive method, carry out this judgement DVB-T signal physical layer bandwidth decision method Checking.

Accompanying drawing 2 is the 5MHz physical layer bandwidth DVB-T signal occupied bandwidth test at Visual Studio platform building Power spectrum chart, calculates, and under display carries a width of 10MHz, its preferable main lobe width is 4.76MHz, occupies general power 99% Frequency range be 4.69MHz, almost enumerate whole channel main lobe portions of bandwidth.

Accompanying drawing 3 is the 6MHz physical layer bandwidth DVB-T signal occupied bandwidth test at Visual Studio platform building Power spectrum chart, calculates, and under display carries a width of 10MHz, its preferable main lobe width is 5.71MHz, occupies general power 99% Frequency range be 5.62MHz, almost enumerate whole channel main lobe portions of bandwidth.

Accompanying drawing 4 is the 7MHz physical layer bandwidth DVB-T signal occupied bandwidth test at Visual Studio platform building Power spectrum chart, calculates, and under display carries a width of 10MHz, its preferable main lobe width is 6.66MHz, occupies general power 99% Frequency range be 6.55MHz, almost enumerate whole channel main lobe portions of bandwidth.

Accompanying drawing 5 is the 8MHz physical layer bandwidth DVB-T signal occupied bandwidth test at Visual Studio platform building Power spectrum chart, calculates, and under display carries a width of 10MHz, its preferable main lobe width is 7.61MHz, occupies general power 99% Frequency range be 7.49MHz, almost enumerate whole channel main lobe portions of bandwidth.

Accompanying drawing 6 can successfully judge DVB-T signal physical layer bandwidth, then when former 12.5M sample rate for utilizing the method In numeric field data, after down-sampled rate is changed, become standard sample rate DVB-T time-domain signal, the letter that final unsuccessful demodulation realizes Number planisphere.

Claims (6)

1. the received terrestrial digital broadcasting TV signal physical layer bandwidth decision method measured based on occupied bandwidth, its feature exists In, comprise the following steps:

Step 1, the received terrestrial digital broadcasting TV signal base band time domain signal that total time span is T is done sample frequency is f_s's Sampling, obtaining frequency range is B_w, data volume be N_allReceived terrestrial digital broadcasting TV signal base band time domain sampled data r, wherein N_all For received terrestrial digital broadcasting TV signal base band time domain samples sum；

Step 2, the base band time domain sampled data r obtaining step 1 carries out windowing and fast discrete Fourier transformation processes and becomes Frequency domain data X；

Step 2.1, chooses window function and base band time domain sampled data r is carried out windowing process, and the formula in this step is as follows:

X (n)=r (n) w (n)

Wherein:

W (n) represents the window function value of nth point；

R (n) represents the base band time domain samples of nth point；

X (n) represents the base band time domain data sample value after nth point windowing；

Step 2.2, makees fast discrete Fourier transformation to the base band time domain data sample value after windowing by the circulation of step-length K and is converted to frequency Numeric field data X, the formula in this step is as follows:

$X\left(k\right)=\underset{n=0}{\overset{K-1}{\Σ}}x\left(n\right)e^{-j\frac{2\mathrm{\π}}{K}nk}$

Wherein:

X (n) represents the base band time domain data sample value after nth point windowing；

X (k) represents kth point frequency domain data sample value；

J represents imaginary unit；

K represents step-length；

N represents base band time domain data sequence number；

K represents frequency domain data sequence number；

π represents pi；

Step 3, signal calculated mid frequency both sides 0.8B altogether_wThe total power signal of bandwidth；

Step 3.1, takes bandwidth B altogether in signal transmission center frequency values both sides in frequency domain data X_wFrequency domain data be designated as X₁, calculate center Frequency both sides bandwidth 0.8B_wOriginal position d of frequency domain data₁With final position d₂, original position d₁With final position d₂Calculating Formula is as follows:

$X\left(d_1\right)=\[X(\stackrel{\‾}{d_1}+1)-X\left(\stackrel{\‾}{d_1}\right)\]\[d_1-\stackrel{\‾}{d_1}\]+X\left(\stackrel{\‾}{d_1}\right)$

$X\left(d_2\right)=\[X(\stackrel{\‾}{d_2}+1)-X\left(\stackrel{\‾}{d_2}\right)\]\[d_2-\stackrel{\‾}{d_2}\]+X\left(\stackrel{\‾}{d_2}\right)$

Wherein:

Represent d respectively₁With d₂Round downwards；

X(d₁) represent in original position d₁The frequency domain data at place estimates sample value；

X(d₂) represent at final position d₂The frequency domain data at place estimates sample value；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Represent in positionThe frequency domain data sample value at place；

Step 3.2, calculates original position d₁With final position d₂Between general power P of frequency-region signal_sum, its formula is as follows:

$P_{sum}=10log\[\frac{Ch\×{\mathrm{Ph}}^2\×Enbw\×S}{nRBW\×{\mathrm{Eh}}^2(\stackrel{\‾}{d_2}-\stackrel{\‾}{d_1})}$

$S=\underset{i=d_1}{\overset{d_2}{\Σ}}\left|X\left(i\right)\right|$

Wherein:

Ch represents bandwidth 0.8B_w；

MRBW represents resolution bandwidth；

Ph represents power gain value；

Eh represents calculating yield value；

Enbw represents window yield value；

Represent d respectively₁With d₂Round downwards；

P_sumRepresent 0.8B_wBandwidth signal general power；

S represents frequency domain data amplitude sum between start-stop position；

X (i) represents the frequency domain data sample value of i-th；

Step 4, calculates and accounts for general power P_sumThe midbandwidth of 99%；

Step 4.1, calculates and accounts for general power P_sumThreshold value P of 0.5%_limit, its formula is:

$P_{\lim it}=10log({10}^{P_{sum}/10}\×0.5\%)$

Wherein:

P_sumRepresent 0.8B_wBandwidth signal general power；

P_limitRepresent and account for general power P_sumThe threshold value of 0.5%；

Step 4.2, at frequency domain data X₁Interior original position d₁With final position d₂In the range of, location left and right side power is respectively Threshold value P_limitApproximate location interval, specific practice is: step-length K is divided into D group, respectively from left side with original position d₁Start To the right, right side is with final position d₂Start the most successively by group accumulation calculating performance number P, when performance number P is first more than threshold value P_limitTime, the class interval that record is added to, i.e. position P_LeftWith P_RightSubstantially place is interval, and these two intervals are designated as substantially district Between A₁With A₂；Described P_LeftWith P_RightRepresent respectively and account for general power P_sumThe bandwidth of 99% start-stop position on frequency domain point；

Step 4.3, calculates the most successively from left side original position d₁To the right to substantially interval A₁Position one by one, right side stop bit Put d₂To the left to substantially interval A₂Performance number P of position one by one, find performance number P for the first time more than threshold value P_limitPosition P_LeftWith P_Right, i.e. interval Z=[P_Left,P_Right] internal power accounts for general power P_sum99%, its conversion bandwidth length BW such as Under:

BW=(P_Right-P_Left)f_s/K

Wherein:

P_LeftWith P_RightRepresent and account for general power P_sumThe bandwidth of 99% start-stop position on frequency domain point；

f_sRepresent sample frequency；

K represents fast discrete Fourier transformation step-length；

Step 5, the threshold value that the physical layer bandwidth of terrestrial digital broadcasting signal judges is respectively BW₁、BW₂、BW₃And BW₄, (0, BW₁]、 (BW₁,BW₂]、(BW₂,BW₃]、(BW₃,BW₄] and (BW₄,+∞) and the most corresponding 2MHz channel, 5MHz channel, 6MHz channel, 7MHz The judgement of channel and 8MHz channel is interval, and the interval that BW is positioned at can obtain the transmission signal physical layer bandwidth mode of correspondence.

A kind of terrestrial digital broadcasting signal physical layer bandwidth decision method the most according to claim 1, it is characterised in that right In terrestrial digital broadcasting signal, the sample frequency described in step 1 is f_sTake 12.5MHz, frequency range B_wFor 12.5MHz, base band time domain is believed Number time span T takes 1ms.

A kind of terrestrial digital broadcasting signal physical layer bandwidth decision method the most according to claim 1, it is characterised in that step K value described in rapid 3 is 4096.

A kind of terrestrial digital broadcasting signal physical layer bandwidth decision method the most according to claim 1, it is characterised in that step D value described in rapid 4 is 20.

A kind of terrestrial digital broadcasting signal physical layer bandwidth decision method the most according to claim 1, it is characterised in that step BW described in rapid 5₁、BW₂、BW₃And BW₄Value is 3.148MHz, 5.2335MHz, 6.185MHz and 7.135MHz respectively.

A kind of terrestrial digital broadcasting signal physical layer bandwidth decision method the most according to claim 1, it is characterised in that step Received terrestrial digital broadcasting TV signal base band time domain signal described in rapid 1 is DVB-T base band time domain signal.