CN103475895A - Frequency spectrum inversion judging device and frequency spectrum inversion judging method - Google Patents

Abstract

The invention provides a frequency spectrum inversion judging device which comprises a differential motion correlator and a judging module. The differential motion correlator is used for applying odd-order differential motion correlation operation on an input signal and a known signal so as to generate a differential motion relevant result. When the input signal is judged as a target signal corresponding to the known signal, the judging module judges whether frequency spectrum inversion exists in the input signal according to the phase of the differential motion relevant result.

Description

Reversing spectrum judgment means and reversing spectrum determination methods

Technical field

Whether the present invention is relevant to wireless communication technology, and especially to judging wireless communication signals, exist the technology of reversing spectrum (spectruminversion) situation relevant.

Background technology

Along with the progress of the communication technology, the development of digital television broadcasting is gradually ripe.Except transmitting via cable line, digital television signal also can the kenel with wireless signal be passed through equipment such as base station or artificial satellites.First generation Digital Television satellite broadcasting (digitalvideobroadcasting – satellite, referred to as DVB-S) standard and second generation Digital Television satellite broadcasting standard (DVB-S2) are all the standards be widely adopted in current this field.

In the DVB-S2 standard, the input signal that the fundamental frequency demodulator of digital television signal receiving terminal receives is process pi/2-skew binary phase offset modulation (pi/2-shiftedbinaryphaseshiftkeying, referred to as BPSK) signal, therefore by same phase constituent (in-phasecomponent) and orthogonal component (quadraturephasecomponent), formed.On practice, the tuner of DVB-S2 receiving terminal (tuner) and mixer (mixer) are likely by mistake by the same phase constituent in signal and orthogonal component exchange, and this is reversing spectrum (spectruminversion) phenomenon.If the fundamental frequency demodulator does not detect this problem early, after finishing, follow-up numerous signal processing flows just find that television system can't correctly start, just must, with after phase constituent and orthogonal component exchange, again carry out these signal processing flows.Hence one can see that, the available machine time of the serious deferred telegram viewing system of problem meeting of reversing spectrum.

Summary of the invention

For addressing the above problem, the present invention proposes a kind of reversing spectrum judgment means and reversing spectrum determination methods, input signal is imposed to the differential related operation of odd number order, and judges according to the phase place of operation result whether this input signal exists the reversing spectrum situation.Can not only be applied among the digital television signal receiving terminal of DVB-S2 standard according to reversing spectrum judgment means of the present invention and reversing spectrum determination methods, also can be extended to signal and have the other system of similar characteristic.

A specific embodiment according to the present invention is a kind of reversing spectrum judgment means, wherein comprises a differential correlator and a judge module.This differential correlator is in order to impose the differential related operation of odd number order to an input signal and a known signal, to produce a differential correlated results.When this input signal is judged as the echo signal corresponding to this known signal, this judge module judges according to the phase place of this differential correlated results whether this input signal exists a reversing spectrum situation.

Another specific embodiment according to the present invention is a kind of reversing spectrum determination methods, and at first the method carries out a calculation step, and an input signal and a known signal are imposed to the differential related operation of odd number order, to produce a differential correlated results.Then, when this input signal is judged as the echo signal corresponding to this known signal, the method carries out a determining step, according to the phase place of this differential correlated results, judges whether this input signal exists a reversing spectrum situation.

About the advantages and spirit of the present invention, can be further understood by following detailed description and accompanying drawings.

The accompanying drawing explanation

Fig. 1 is the calcspar according to the reversing spectrum judgment means in one embodiment of the invention.

Fig. 2 is the example that reversing spectrum judgment means according to the present invention further comprises a control module.

Fig. 3 (A) and Fig. 3 (B) are in order to present the analog result adopted according to the solution of the present invention gained.

Fig. 4 is according to the reversing spectrum determination methods flow chart in one embodiment of the invention.

The main element symbol description

100: reversing spectrum judgment means 12: differential correlator

14: judge module 14A: phase detecting circuit

16: control module

Embodiment

Be the reversing spectrum judgment means 100 shown in Fig. 1 according to one embodiment of the invention, wherein comprise differential correlator (differentialcorrelator) 12 and judge module 14.In actual applications, reversing spectrum judgment means 100 can be incorporated in the digital television signal receiving terminal that adopts the DVB-S2 standard, but not as limit.

According to the DVB-S2 standard, the beginning of Frame zone (startofframe, referred to as SOF) comprises 26 symbols (symbol) S altogether ₀~ S ₂₅, S wherein ₀, S ₂, S ₄..., S ₂₄deng 13 symbols, homophase (in-phase) composition separately is identical and positive and negative identical with quadrature (quadrature) composition size; Moreover, S ₁, S ₃, S ₅..., S ₂₅identical with the orthogonal component size and positive and negative contrary etc. other 13 symbols same phase constituent separately.If indicate these symbols, S in complex number plane ₀, S ₂, S ₄..., S ₂₄there will be at first quartile or third quadrant S Deng symbol ₁, S ₃, S ₅..., S ₂₅deng symbol, there will be in the second quadrant or fourth quadrant.

Based on above-mentioned symbol characteristic, even the situation of reversing spectrum, the symbol S after reversion occur ₀, S ₂, S ₄..., S ₂₄the quadrant at place can't change, that is maintains first quartile or third quadrant.But, symbol S ₁, S ₃, S ₅..., S ₂₅can be subject to the impact of reversing spectrum and change its quadrant.More particularly, while reversing originally the symbol at the second quadrant after reversion, not there will be in fourth quadrant, and while not reversing originally the symbol in fourth quadrant after reversion, there will be at the second quadrant.In other words, if there is the situation of reversing spectrum, the symbol S in the initiation region of DVB-S2 Frame ₀, S ₂, S ₄..., S ₂₄can not change, but symbol S during reversing spectrum ₁, S ₃, S ₅..., S ₂₅symbol S while not reversing with frequency spectrum ₁, S ₃, S ₅..., S ₂₅differ a negative sign.

The standard content of the initiation region of DVB-S2 Frame is known to receiving terminal.Therefore, reversing spectrum judgment means 100 can be set a known signal S as reference frame, the standard content s of the initiation region that it comprises the DVB-S2 Frame ₀~ s ₂₅.Below at first explanation supposes that reversing spectrum judgment means 100 confirmed that an input signal R is for the initiation region of certain DVB-S2 Frame, but still whether uncertain input signal R exists the reversing spectrum situation.

If there is not the reversing spectrum situation in input signal R, i symbol r wherein _iwith i symbol s in known signal S _ipass be:

R _i=s _ie ^{j2 π f (iT)}for i=0,1,2,3 ..., (N-1), (formula one)

T represents the Cycle Length of these symbols, f represent when input signal R enters differential correlator 12 with carrier frequency shift (carrierfrequencyoffset, referred to as CFO), N represents input signal R and each self-contained symbol quantity of known signal S (in this example, equaling 26).

After receiving input signal R, 12 couples of input signal R of differential correlator and known signal S carry out the differential related operation of at least one odd number order.In the present embodiment, the following equation signifier is a step differential related operation, and differential correlator 12 can produce differential correlated results d1:

$d_1=\underset{i=1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-1}{s}_{i-1}^{*},$ (formula two)

According to formula one, formula two can be as follows by abbreviation:

$d_1=(s_1^{*}{s}_1{s}_0{s}_0^{*}+s_2^{*}{s}_2{s}_1{s}_1^{*}+...+s_{25}^{*}{s}_{25}{s}_{24}{s}_{24}^{*})\·e^{-j2\mathrm{\πfT}}$

$=({\left|s_1\right|}^2{\left|s_0\right|}^2+{\left|s_2\right|}^2{\left|s_1\right|}^2+...+{\left|s_{25}\right|}^2{\left|s_{24}\right|}^2)\·e^{-j2\mathrm{\πfT}},$ (formula three)

By formula three, can be found out, when there is not the reversing spectrum situation in input signal R, differential correlated results d ₁phase place Arg (d ₁) be (2 π fT); If carrier frequency shift f levels off to zero, Arg (d ₁) also level off to zero.On practice, after reversing spectrum judgment means 100 can be arranged at an offset correction of carrier frequency device, carrier frequency shift f is dwindled as far as possible.

Relatively, if there is the reversing spectrum situation in input signal R, i symbol r wherein _iwith i symbol s in known signal S _ipass be:

$\left\{\begin{array}{cc}{r}_i=s_i{e}^{j2\mathrm{\πf}\left(\mathrm{iT}\right)}& \mathrm{fori}=\mathrm{0,2,4,6,8}...\\ r_i=s_i{e}^{j2\mathrm{\πf}\left(\mathrm{iT}\right)}\·e^{\mathrm{j\π}}& \mathrm{fori}=\mathrm{1,3,5,7,9}...\end{array}\right.,$ (formula four)

If can obtain according to formula four rewriting formulas two:

$d_1=(s_1^{*}{s}_1{s}_0{s}_0^{*}+s_2^{*}{s}_2{s}_1{s}_1^{*}+...+s_{25}^{*}{s}_{25}{s}_{24}{s}_{24}^{*})\·e^{-j2\mathrm{\πfT}}\·e^{\mathrm{j\π}}$

$=({\left|s_1\right|}^2{\left|s_0\right|}^2+{\left|s_2\right|}^2{\left|s_1\right|}^2+...+{\left|s_{25}\right|}^2{\left|s_{24}\right|}^2)\·e^{-j2\mathrm{\πfT}}\·e^{\mathrm{j\π}}.$ (formula five)

By formula five, can be found out, when there is the reversing spectrum situation in input signal, differential correlated results d ₁phase place Arg (d ₁) be (2 π fT+ π); If carrier frequency shift f levels off to zero, Arg (d ₁) level off to π.

As shown in Figure 1, a phase detecting circuit 14A can be set in judge module 14, in order to judge differential correlated results d ₁phase place Arg (d ₁).Subsequently, judge module 14 can be according to Arg (d ₁) judge whether input signal R exists the reversing spectrum situation.For example, can to set threshold value be pi/2 to judge module 14; If the Arg (d corresponding to an input signal ₁) being less than pi/2, judge module 14 judges that there is not the reversing spectrum situation in this input signal.Relatively, if the Arg (d of an input signal ₁) being greater than pi/2, judge module 14 just notifies subsequent conditioning circuit in-phase signal and orthogonal signalling must be exchanged.

The method that may there is no when in actual applications, reversing spectrum judgment means 100 is received an input signal determines whether this input signal is the initiation region of certain DVB-S2 Frame.In theory, if an input signal is the initiation region of DVB-S2 Frame really, the degree of correlation between this input signal and aforementioned known signal must be not low, makes differential correlated results d ₁absolute value must surpass certain threshold value.Relatively, if an input signal is not the initiation region of DVB-S2 Frame, its differential correlated results d ₁absolute value can be less than this threshold value.Therefore, the differential correlated results d that differential correlator 12 produces ₁also can be as judging whether an input signal is the foundation of the initiation region of DVB-S2 Frame.

In sum, for an input signal, judge module 14 at first can be according to its differential correlated results d ₁absolute value | d _m1| judge whether this input signal is the initiation region of DVB-S2 Frame.If this judgment result is that, be that judge module 14 is just further according to differential correlated results d ₁phase place Arg (d ₁) judge whether this input signal exists the reversing spectrum situation.

Should be noted that, the performed computing of differential correlator 12 is not limited to an above-mentioned step differential related operation.One input signal R and known signal S are imposed to the differential correlated results dm that m step differential related operation produces can be expressed as follows:

$d_m=\underset{i=m}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m}{s}_{i-m}^{*}.$ (formula six)

According to formula one, formula six can be as follows by abbreviation:

$d_m=(s_m^{*}{s}_m{s}_0{s}_0^{*}+s_{m+1}^{*}{s}_{m+1}{s}_1{s}_1^{*}+...+s_{25}^{*}{s}_{25}{s}_{25-m}{s}_{25-m}^{*})\·e^{-j2\mathrm{\πf}\left(\mathrm{mT}\right)}$

When m is even number, according to the result of formula four rewriting formula six gained, can obtain:

D _m=(| s _m| ²| s ₀| ²+ | s _m+1| ²| s ₁| ²+ ...+| s ₂₅| ²| s _25-m| ²) e ^{-j2 π f (mT)}, (formula seven)

When m is odd number, according to formula four rewriting formulas six, can obtain:

D _m=(| s _m| ²| s ₀| ²+ | s _m+1| ²| s ₁| ²+ ...+| s ₂₅| ²| s _25-m| ²) e ^{-j2 π f (mT)}e ^{j π}, (formula eight)

By formula seven and formula eight, can be found out if m is even number, no matter whether have the reversing spectrum situation, differential correlated results d _mphase place Arg (d _m) be all [2 π f (mT)].If m is odd number, there do not is the corresponding Arg (d of input signal of reversing spectrum situation _m) be [2 π f (mT)], there is the corresponding Arg (d of input signal of reversing spectrum situation _m) be [2 π f (mT)+π].Easy speech, only have the differential related operation of odd number order, just can produce and can judge according to this whether input signal exists the differential correlated results of reversing spectrum situation.Therefore, differential correlator 12 is designed at least carry out an odd number order (single order, three rank, five rank ...) differential related operation.

On practice, the result that the inferior differential related operation of higher-order produces is relatively accurate.As shown in Figure 2, reversing spectrum judgment means 100 can further comprise a control module 16, in order to the channel environment passed through according to input signal, determines the order m that differential correlator 12 should adopt.Channel environment is poorer, and control module 16 can be selected the order m of healing large, improves by this accuracy.In one embodiment, for good channel environment, even control module 16 order m are 1; For severe channel environment, even control module 16 order m are 3.

In another embodiment, differential correlator 12 is designed to simultaneously or successively carries out the differential related operation of at least two different odd-order time (m1, m2):

$d_{m1}=\underset{i=m1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m1}{s}_{i-m1}^{*}$ And $d_{m2}=\underset{i=m2}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m2}{s}_{i-m2}^{*}.$

Accordingly, judge module 14 can be designed to simultaneously with reference to the first differential correlated results d _m1phase place Arg (d _m1) and the second differential correlated results d _m2phase place Arg (d _m2) judge whether input signal exists the reversing spectrum situation.For example, judge module 14 can be according to Arg (d _m1) * w1+Arg (d _m2) whether * w2 judge higher than a threshold value whether input signal exists the reversing spectrum situation, w1, the w2 proportion parameter for predetermining wherein.In addition, judge module 14 also can be according to the first differential correlated results d _m1absolute value | d _m1| with the second differential correlated results d _m2absolute value | d _m2|, (for example | d _m1| with | d _m2| summation), judge whether input signal is the initiation region of DVB-S2 Frame.

In another embodiment, differential correlator 12 can be designed to optionally produce the second differential correlated results d _m2.For example, the control module in Fig. 2 16 can determine whether to need to produce the second differential correlated results d according to channel environment _m2.If it is severe that the determination result of control module 16 is current channel environment, differential correlator 12 just additionally produces the second differential correlated results d _m2, otherwise only produce the first differential correlated results d _m1.

In another embodiment, differential correlator 12 is designed to simultaneously or successively carries out the differential related operation of an odd number order (m1) and an even number order (m3):

$d_{m1}=\underset{i=m1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m1}{s}_{i-m1}^{*}$ And $d_{m3}=\underset{i=m3}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m3}{s}_{i-m3}^{*}.$

Take m1 as 1, m3 is as 2 being example, when there is not the reversing spectrum situation in input signal, differential correlated results d ₁phase place Arg (d1) equal (2 π fT), differential correlated results d ₂phase place Arg (d ₂) equal (4 π fT); Phase difference [Arg (d ₁)-Arg (d ₂)] be (2 π fT).Relatively, when there is the reversing spectrum situation in input signal, the phase place Arg (d of differential correlated results d1 ₁) equal (2 π fT+ π), the phase place Arg (d of differential correlated results d2 ₂) equal (4 π fT); Phase difference [Arg (d ₁)-Arg (d ₂)] be (2 π fT+ π).Based on above-mentioned phase difference characteristic, because carrier frequency shift f levels off to zero, judge module 14 also can be according to the first differential correlated results d _m1with the 3rd differential correlated results d _m3phase difference [Arg (d _m1)-Arg (d _m3)] find out whether input signal exists the reversing spectrum situation.

On the other hand, even differential correlated results d _m3phase place Arg (d _m3) can't be separately as judging whether input signal exists the foundation of reversing spectrum situation, differential correlated results d _m3absolute value | d _m3| still have a reference value.For example, judge module 14 can be according to the first differential correlated results d _m1absolute value | d _m1| with the 3rd differential correlated results d _m3absolute value | d _m3|, (for example | d _m1| with | d _m3| summation), judge whether input signal is the initiation region of DVB-S2 Frame.

On practice, differential correlator 12 also can be designed to carry out a plurality of odd number orders and the differential related operation of a plurality of even number orders.For example, differential correlator 12 can be carried out four kinds of differential related operations such as single order, second order, three rank, quadravalence simultaneously for an input signal.Under these circumstances, judge module 14 can be according to the absolute value summation of four operation results, judge whether this input signal is the initiation region of DVB-S2 Frame, and only according to the phase place of the result of single order and three step differential related operations, judge whether this input signal exists the reversing spectrum situation.

Should be noted that, 100 treatable input signals of reversing spectrum judgment means are not limited with the initiation region of DVB-S2 Frame; So long as there is the signal (s of same nature _2jsame phase constituent and orthogonal component size identical and positive and negative identical, s _2j+1same phase constituent and orthogonal component size identical and positive and negative contrary) all be applicable to aforementioned determining program.

For example, provide to the input signal of reversing spectrum judgment means 100 and also can further comprise the physical layer signal code (physicallayersignalingcode followed behind the initiation region of DVB-S2 Frame, referred to as PLSC), or only comprise the part section of the initiation region of DVB-S2 Frame.

Table content in Fig. 3 (A) and Fig. 3 (B) is than (signaltonoiseratio for the unlike signal noise, referred to as SNR) the analog result that produces of the white gaussian noise of additivity (additivewhiteGaussiannoise, referred to as AWGN) passage.SR conventional letter rate (symbolrate).

By these two forms, can be found out, when there is not the reversing spectrum situation in input signal, the phase place of the differential correlated results of single order ~ quadravalence is all quite little.When there is the reversing spectrum situation in input signal, the phase place of single order and three step differential correlated results all quite approaches π.Known according to these analog results, really can effectively judge according to reversing spectrum judgment means 100 of the present invention whether input signal exists the reversing spectrum situation.

Be the reversing spectrum determination methods according to another embodiment of the present invention, its flow chart as shown in Figure 4.At first, step S41 is for to impose following m1 step differential related operation (m1 is odd number) to an input signal and a known signal, to produce the first differential correlated results d _m1:

$d_{m1}=\underset{i=m1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m1}{s}_{i-m1}^{*}.$

Step S42 is judged as the echo signal corresponding to this known signal when this input signal, according to this first differential correlated results d _m1phase place judge whether this input signal exists a reversing spectrum situation.

Previous several circuit operation flow change of describing when introducing reversing spectrum judgment means 100, (for example before step S42, first judge whether this input signal is echo signal, carry out two different odd-order time differential related operation, carry out the differential related operation of an odd number order and an even number order ...), also can be applied in the reversing spectrum determination methods that Fig. 4 illustrates, its details repeats no more.

As mentioned above, the present invention proposes a kind of reversing spectrum judgment means and reversing spectrum determination methods, input signal is imposed to the differential related operation of odd number order, and judges according to the phase place of operation result whether this input signal exists the reversing spectrum situation.Can not only be applied among the digital television signal receiving terminal of DVB-S2 standard according to reversing spectrum judgment means of the present invention and reversing spectrum determination methods, also can be extended to signal and have the other system of similar characteristic.

By the above detailed description of preferred embodiments, hope can be known description feature of the present invention and spirit more, and not with the above-mentioned preferred embodiment disclosed, category of the present invention is limited.On the contrary, its objective is that hope can contain in the category of the scope of the claims of being arranged in of various changes and tool equality institute of the present invention wish application.

Claims (24)

1. a reversing spectrum judgment means comprises:

One differential correlator, in order to an input signal and a known signal are imposed to the differential related operation of odd number order, to produce one first differential correlated results d _m1; And

One judge module, be coupled to this differential correlator, and when this input signal is judged as the echo signal corresponding to this known signal, this judge module is according to this first differential correlated results d _m1phase place judge whether this input signal exists a reversing spectrum situation.

2. reversing spectrum judgment means as claimed in claim 1, is characterized in that, this judge module is according to this first differential correlated results d _m1absolute value judge whether this input signal is this echo signal.

3. reversing spectrum judgment means as claimed in claim 1, is characterized in that, the differential related operation of this odd number order comprises:

$d_{m1}=\underset{i=m1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m1}{s}_{i-m1}^{*}$

Wherein, the odd number order represents that order m1 is odd number, each self-contained N symbol of this input signal and this known signal, r _irepresent i symbol in this input signal, s _irepresent i symbol in this known signal, s _2jsame phase constituent and orthogonal component size identical and positive and negative identical, s _2j+1same phase constituent and orthogonal component size identical and positive and negative contrary, N is greater than 1 integer, i be scope 0 to the integer index between (N-1), j be scope 0 to the integer index between (N/2-1).

4. reversing spectrum judgment means as claimed in claim 3, is characterized in that, also comprises:

Single order time control module, determine in order to the channel environment passed through according to this input signal the order m1 that this differential correlator adopts, and this channel environment is poorer, and this control module is selected the order m1 of healing large.

5. reversing spectrum judgment means as claimed in claim 1, is characterized in that, this differential correlator also produces the one second differential correlated results d corresponding to the different odd order _m2; And

This judge module is according to this first differential correlated results d _m1phase place and this second differential correlated results d _m2phase place judge whether this input signal exists this reversing spectrum situation.

6. reversing spectrum judgment means as claimed in claim 5, is characterized in that, this judge module is according to this first differential correlated results d _m1absolute value and this second differential correlated results d _m2absolute value judge whether this input signal is this echo signal.

7. reversing spectrum judgment means as claimed in claim 1, is characterized in that, also comprises:

One environment measuring module, the channel environment passed through in order to detect this input signal, determine whether to produce the one second differential correlated results d corresponding to the different odd order according to this _m2;

Wherein, if the determination result of this environment measuring module is yes, this differential correlator produces this second differential correlated results d _m2,

This judge module is according to this first differential correlated results d _m1phase place and this second differential correlated results d _m2phase place judge whether this input signal exists this reversing spectrum situation.

8. reversing spectrum judgment means as claimed in claim 7, is characterized in that, this judge module is according to this first differential correlated results d _m1absolute value and this second differential correlated results d _m2absolute value judge whether this input signal is this echo signal.

9. reversing spectrum judgment means as claimed in claim 1, is characterized in that, this differential correlator also produces one the 3rd differential correlated results d corresponding to an even number order _m3; And

This judge module is according to this first differential correlated results d _m1with the 3rd differential correlated results d _m3phase difference, judge whether this input signal exists this reversing spectrum situation.

10. reversing spectrum judgment means as claimed in claim 9, is characterized in that, this judge module is according to this first differential correlated results d _m1absolute value and the 3rd differential correlated results d _m3absolute value, judge whether this input signal is this echo signal.

11. reversing spectrum judgment means as claimed in claim 1, is characterized in that, the initiation region content that this input signal comprises a second generation Digital Television satellite broadcasting Frame.

12. reversing spectrum judgment means as claimed in claim 11, is characterized in that, this known signal comprises the content met in this second generation Digital Television satellite broadcast standard relevant for the Frame initiation region.

13. reversing spectrum judgment means as claimed in claim 1, is characterized in that, be to be applied in a digital baseband demodulating equipment, and this digital baseband demodulating equipment receives this input signal formed with the phase deviation modulation.

14. a reversing spectrum determination methods comprises following steps:

(a) input signal and a known signal are imposed to the differential related operation of odd number order, to produce one first differential correlated results d _m1; And

(b) be judged as the echo signal corresponding to this known signal when this input signal, according to this first differential correlated results d _m1phase place judge whether this input signal exists a reversing spectrum situation.

15. reversing spectrum determination methods as claimed in claim 14, is characterized in that, further comprises following steps between step (a) and step (b): according to this first differential correlated results d _m1absolute value judge whether this input signal is this echo signal.

16. reversing spectrum determination methods as claimed in claim 14, is characterized in that, the differential related operation of this odd number order comprises:

$d_{m1}=\underset{i=m1}{\overset{N-1}{\mathrm{\Σ}}}{r}_i^{*}{s}_i{r}_{i-m1}{s}_{i-m1}^{*}$

Wherein, the odd number order represents that order m1 is odd number, each self-contained N symbol of this input signal and this known signal, r _irepresent i symbol in this input signal, s _irepresent i symbol in this known signal, s _2jsame phase constituent and orthogonal component size identical and positive and negative identical, s _2j+1same phase constituent and orthogonal component size identical and positive and negative contrary, N is greater than 1 integer, i be scope 0 to the integer index between (N-1), j be scope 0 to the integer index between (N/2-1).

17. reversing spectrum determination methods as claimed in claim 16, is characterized in that, further comprises before in step (a):

The order m1 that a channel environment deciding step (a) of passing through according to this input signal adopts, this channel environment is poorer, selects the order m1 of healing large.

18. reversing spectrum determination methods as claimed in claim 14, is characterized in that, step (a) further comprises generation one second differential correlated results d _m2; And

Step (b) is according to this first differential correlated results d _m1phase place and this second differential correlated results d _m2phase place judge whether this input signal exists this reversing spectrum situation.

19. reversing spectrum determination methods as claimed in claim 18, is characterized in that, further comprises following steps between step (a) and step (b): according to this first differential correlated results d _m1absolute value and this second differential correlated results d _m2absolute value, judge whether this input signal is this echo signal.

20. reversing spectrum determination methods as claimed in claim 14, is characterized in that, further comprises:

The channel environment passed through according to this input signal, determine whether to produce the one second differential correlated results d corresponding to the different odd order _m2; If produce this second differential correlated results d _m2

, and step (b) is according to this first differential correlated results d _m1phase place and this second differential correlated results d _m2phase place, judge whether this input signal exists this reversing spectrum situation.

21. reversing spectrum determination methods as claimed in claim 20, is characterized in that, further comprises following steps between step (a) and step (b): according to this first differential correlated results d _m1absolute value and this second differential correlated results d _m2absolute value judge whether this input signal is this echo signal.

22. reversing spectrum determination methods as claimed in claim 14, is characterized in that, step (a) further comprises one the 3rd differential correlated results d produced corresponding to an even number order _m3, and step (b) is according to this first differential correlated results d _m1with the 3rd differential correlated results d _m3phase difference judge whether this input signal exists this reversing spectrum situation.

23. reversing spectrum determination methods as claimed in claim 22, is characterized in that, further comprises between step (a) and step (b):

According to this first differential correlated results d _m1absolute value and the 3rd differential correlated results d _m3absolute value judge whether this input signal is this echo signal.

24. reversing spectrum determination methods as claimed in claim 14, is characterized in that, the initiation region that this input signal comprises a second generation Digital Television satellite broadcasting Frame.

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