CN112020830A - Method and device for broadcasting text signal based on phase discontinuous R-CSK modulation - Google Patents

Abstract

The invention discloses a method and a device for broadcasting telegraph text signals based on phase discontinuous R-CSK modulation, wherein the method comprises the following steps: modulating the basic message on the in-phase I branch, carrying out BPSK-DSSS direct sequence spread spectrum on the basic message, and constructing an in-phase I branch baseband signal; modulating the spread message on the orthogonal Q branch, performing phase non-continuous R-CSK-DSSS direct sequence spread spectrum on the spread message, and constructing an orthogonal Q branch baseband signal; when the spread message is modulated, determining a pseudorandom spread spectrum sequence for each symbol to be modulated, and keeping a fixed phase interval between two symbols to be modulated which are adjacent in value by adopting a cyclic shift mode on a basic pseudorandom spread spectrum sequence, wherein the fixed phase interval is at least larger than the chip phase of one pseudorandom spread spectrum sequence, namely the phase interval between the initial phases (taking the chip as a unit) of the pseudorandom spread spectrum sequences which are respectively corresponding to two modulation symbols which are adjacent in any value is a fixed value and has a difference of more than two chips; and carrying out IQ quadrature modulation on the basic message baseband signal of the in-phase I branch and the expanded message baseband signal of the quadrature Q branch to form a double-rate composite message signal and broadcast the double-rate composite message signal.

Description

Method and device for broadcasting text signal based on phase discontinuous R-CSK modulation

technical field

The invention relates to a method and a device for broadcasting a message signal based on phase discontinuous R-CSK modulation, belonging to the technical field of communication and navigation signal design.

Background technique

In the design of contemporary communication and navigation systems, according to different application requirements, it is often necessary to broadcast composite messages that meet different requirements in the signal of the same frequency point at the same time. For example, basic telegrams are broadcast at a certain information rate to meet the requirements of the system's basic service performance or public service performance, while extended telegrams with the same or different information rates are broadcast to meet the system's additional service performance or non-public service performance requirements. Since the extended message signal may not be fully disclosed, the system requires the designed composite message signal to ensure that the basic message user can receive the basic message in the composite message signal with good performance without knowing whether the extended message signal exists or not.

For communication and navigation systems using the direct-sequence spread spectrum signal system, the rate of broadcast messages is generally less than the reciprocal of the spread spectrum code period. For example, the spreading code period of the GPS L1 C/A code in the United States is 1ms, and the rate of the navigation message is 50bps; the spreading code period of the WAAS satellite navigation satellite-based augmentation system is 1ms, and the rate of the navigation message is 500sps. If the transmission rate of the message is to be improved, the code length of the spreading code should be shortened, or the polarity of the spreading code should be reversed several times in a code period, which will reduce the correlation characteristics of signal reception and tracking, and damage the signal reception performance.

On the other hand, for the Japanese QZSS quasi-zenith satellite navigation system, which also uses the code shift keying modulation method (CSK modulation method for short) to broadcast telegrams, in order to provide the necessary spread spectrum code chips and code cycle time information for CSK demodulation , The QZSS system designs a dedicated pilot channel that does not broadcast the message in the L6 signal that broadcasts the CSK modulated message. The pilot channel signal and the message broadcast signal are combined by TDM time division multiplexing and broadcast in the same carrier phase.

In order to reduce the bit error rate of CSK demodulation, an intuitive solution is to repeatedly broadcast the spread spectrum code sequence modulated by a given information symbol to increase the signal broadcast energy of a single modulation symbol. At the same time, in order to avoid the problem of decreasing the information rate due to repeated broadcasting, the number of information bits occupied by a single modulation symbol is increased in the same proportion to keep the information rate unchanged. For such a CSK modulation scheme, this patent refers to a repetitive phase-shift code-shift keying modulation scheme (abbreviated as R-CSK modulation scheme).

Usually, for the convenience of engineering implementation, CSK/R-CSK modulation generally adopts the phase sequence advance or phase sequence lag mode, assigns different PRN (pseudo-random noise) phases to the modulation information symbols one by one, and maps the modulation information to the PRN code a continuous phase region. When there is multipath interference, the CSK/R-CSK modulated signal using this phase configuration is prone to generate large correlation peak side lobes at the output of the signal demodulator, which interferes with the CSK/R-CSK demodulation decision and increases the CSK /R-CSK demodulation bit error rate.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a teletext signal broadcast control method based on phase discontinuous R-CSK modulation, which can effectively solve the requirements for broadcasting multi-type telegram services in the application of communication and navigation systems, and has good multipath suppression performance. device.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

The present invention provides a method for broadcasting a message signal based on phase discontinuous R-CSK modulation, comprising:

Modulate the basic message on the in-phase I branch, perform BPSK-DSSS direct-sequence spread spectrum on the basic message, and construct the in-phase I branch baseband signal;

The extended message is modulated on the quadrature Q branch, and the phase non-continuous R-CSK-DSSS direct-sequence spread spectrum is performed on the extended message to construct the quadrature Q branch baseband signal; The modulation symbol determines a pseudo-random spread spectrum sequence, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence, and the fixed phase interval is at least greater than one The chip phase of the pseudorandom spread spectrum sequence, that is, the phase interval between the initial phases (in chips) of the pseudorandom spread spectrum sequence corresponding to two adjacent modulation symbols of any value is a fixed value, and the difference is two chip or more;

Perform IQ quadrature modulation on the basic teletext baseband signal of the in-phase I branch and the extended teletext baseband signal of the quadrature Q branch to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain a radio frequency carrier signal. Amplify and process to form a double-rate composite message signal, which is handed over to the transmitting antenna for broadcast.

As a preferred technical solution of the present invention: assuming that the phase interval is Z, when any value in the to-be-modulated message is expressed as i, the initial phase of the pseudo-random spread spectrum sequence is PRN(i*Z); i= 0～M-1, M is the number of information symbols of the message to be modulated, and the value of Z is greater than or equal to 2 chips and M*Z is less than or equal to the number of chips corresponding to a pseudo-random spread spectrum sequence period.

As a kind of preferred technical scheme of the present invention: in the above-mentioned dissemination method of message signal based on phase discontinuous R-CSK modulation, on the in-phase I branch, construct the in-phase I branch baseband signal as follows:

Channel coding is performed on the basic message to obtain the coded bit stream _DB (t);

According to the basic message spreading code periodic clock and Chip clock provided by the timing generator, the basic message spreading code _{C B} (t) is generated by the basic message spreading code generator. t) perform BPSK-DSSS direct-sequence spread spectrum modulation, and update the corresponding bit stream of the basic message as C _B (t) D _B (t);

Based on the power ratio coefficient A _I of the preset basic message, the in _- phase I branch baseband signal S _I (t) is obtained according to S _I (t)=A _I ·C _B (t)·DB (t).

As a preferred technical solution of the present invention: in the above-mentioned method for broadcasting a message signal based on phase discontinuous R-CSK modulation, on the quadrature Q branch, the quadrature Q branch baseband signal is constructed as follows:

Channel coding is performed on the extended message to obtain the coded bit stream;

According to the extended message symbol clock provided by the timing generator, 1->K _R bit serial/parallel conversion is performed on the corresponding bit stream after extended message encoding to obtain a parallel data stream; the duration of each K _R bit of parallel data is the symbol time. The length is equal to N times the cycle time of the spreading code of the extended message;

According to the extended message spread spectrum code periodic clock provided by the timing generator, the phase selection module generates the phase offset corresponding to the parallel data stream according to the preset phase equal interval non-continuous mapping relationship;

并结合预设扩展电文功率配比系数A_Q，按

获得伪随机扩频序列S_Q(t)，即正交Q支路基带信号S_Q(t)，其中，伪随机扩频序列的码相位受扩展电文控制，(A_I)²+(A_Q)²＝1。其中，当基于所述扩展电文扩频码不重复进行相位等间隔非连续配置码移键控调制时，这种调制方式即为CSK调制。According to the extended message code cycle clock, the chip clock, and the phase offset corresponding to the parallel data stream provided by the timing generator, the extended message spread spectrum code generator generates the extended message spread spectrum code, and based on the extended message spread spectrum code The code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-consecutive configuration code shift keying modulation is performed to obtain the modulated spread text spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

Obtain the pseudo-random spreading sequence S _Q (t), that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message, (A _I ) ² +(A _Q ) ² = 1. Wherein, when the phase and equally spaced discontinuous configuration code shift keying modulation is not repeated based on the spread spectrum code of the spread message, this modulation mode is CSK modulation.

As a preferred technical solution of the present invention, the extended electronic text symbol clock is an integer multiple of the extended electronic text code period clock, and is synchronized with the extended electronic text code period clock.

The present invention also provides an apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation, comprising:

The first modulation unit is used to modulate the basic message on the in-phase I branch, and perform BPSK-DSSS direct-sequence spread spectrum on the basic message to construct the in-phase I branch baseband signal;

The second modulation unit is used to modulate the extended message on the quadrature Q branch, perform phase non-continuous R-CSK-DSSS direct-sequence spread spectrum on the extended message, and construct the quadrature Q branch baseband signal; During modulation, a pseudo-random spread spectrum sequence is determined for each symbol to be modulated, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence. The fixed phase interval is at least greater than the chip phase of a pseudo-random spreading sequence, that is, the phase interval between the initial phases (in chips) of the pseudo-random spreading sequences corresponding to two adjacent modulation symbols of any value is Fixed value, and the difference is more than two chips;

The carrier modulation unit is used to perform IQ quadrature modulation on the basic teletext baseband signal of the in-phase I branch and the extended teletext baseband signal of the quadrature Q branch to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain a radio frequency carrier signal;

The sending unit is used to amplify the radio frequency carrier signal to form a double-rate composite message signal for broadcasting.

As a preferred technical solution of the present invention: assuming that the phase interval is Z, when any value in the to-be-modulated message is expressed as i, the initial phase of the pseudo-random spread spectrum sequence is PRN(i*Z); i= 0～M-1, M is the number of information symbols of the message to be modulated, and the value of Z is greater than or equal to 2 chips and M*Z is less than or equal to the number of chips corresponding to a pseudo-random spread spectrum sequence period.

As a preferred technical solution of the present invention, in the apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation in the embodiment of the present invention, the first modulation unit includes:

_A coding subunit, used for channel coding the basic message to obtain the coded bit stream DB (t);

The first spread spectrum modulation subunit is used for generating the basic message spread spectrum code C _B (t) from the basic message spread spectrum code generator according to the basic message spread spectrum code periodic clock and the Chip clock provided by the timing generator, and for all The bit stream DB (t) corresponding to the basic message is obtained and subjected to BPSK-DSSS direct-sequence spread spectrum modulation, and the bit stream corresponding to the updated basic message is C _B (t) _{D B (} t);

The baseband signal generation subunit is used to obtain the baseband signal of the in-phase I branch according to S _I (t)=A _I C _B (t) D _B (t) based on the power ratio coefficient A _I of the preset basic message S _I (t).

As a preferred technical solution of the present invention, in the apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation in the embodiment of the present invention, the second modulation unit includes:

an encoding subunit, used to perform channel encoding on the extended telegram to obtain an encoded bit stream;

The serial/parallel conversion subunit is used to perform 1->K _R bit serial/parallel conversion on the corresponding bit stream encoded by the extended message according to the extended message symbol clock provided by the timing generator to obtain a parallel data stream; in which every K _R The duration of bit parallel data, that is, the symbol time length is equal to N times the cycle time of the spreading code of the spread message;

The phase offset subunit is used to generate the phase offset corresponding to the parallel data stream by the phase selection module according to the preset phase equal interval non-continuous mapping relationship according to the extended message spread spectrum code periodic clock provided by the timing generator;

并结合预设扩展电文功率配比系数A_Q，按

获得伪随机扩频序列S_Q(t)，即正交Q支路基带信号S_Q(t)，其中，伪随机扩频序列的码相位受扩展电文控制，(A_I)²+(A_Q)²＝1。其中，当基于所述扩展电文扩频码不重复进行相位等间隔非连续配置码移键控调制时，这种调制方式即为CSK调制。The second spread spectrum modulation subunit is used to generate the spread spectrum code of the spread telegram according to the period clock of the spread telegram code, the chip clock and the phase offset corresponding to the parallel data stream provided by the timing generator, and based on the spread telegram The spread spectrum code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-continuous configuration code shift keying modulation is performed to obtain the modulated spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

Obtain the pseudo-random spreading sequence S _Q (t), that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message, (A _I ) ² +(A _Q ) ² = 1. Wherein, when the phase and equally spaced discontinuous configuration code shift keying modulation is not repeated based on the spread spectrum code of the spread message, this modulation mode is CSK modulation.

As a preferred technical solution of the present invention, the extended electronic text symbol clock is an integer multiple of the extended electronic text code period clock, and is synchronized with the extended electronic text code period clock.

Compared with the prior art, the teletext signal broadcasting method based on phase discontinuous R-CSK modulation of the present invention has the following excellent effects:

The method for broadcasting a message signal based on phase discontinuous R-CSK modulation of the present invention adopts IQ two-way quadrature modulation, wherein the in-phase I branch adopts BPSK binary phase shift keying carrier modulation, and the baseband signal is DSSS direct sequence spread spectrum. Basic message; BPSK binary phase shift keying carrier modulation is used on the quadrature Q branch, and the baseband signal is a pseudo-random pseudo-random configuration code shift keying modulation with equal intervals of phase that is repeated for many times, or repeated zero times, that is, the phase shift is not repeated. Spread spectrum sequence, the code phase of the pseudo-random sequence is controlled by the broadcast spread message; under the condition of the same spread spectrum code length or period, the CSK modulation method can be used to obtain a higher message broadcast rate than DSSS direct sequence spread spectrum; Compared with the conventional CSK modulation system, the invention can effectively improve the demodulation performance of the receiver under the condition that the effective information rate of broadcast is the same because the code shift keying modulation with repeated phase shift is adopted; it can improve the transmission of CSK modulation information. At the same time, the signal power density of the receiving end is kept unchanged, and the software and hardware cost and power consumption of the demodulation of the CSK message at the receiving end are avoided to be greatly increased; , which differ from each other by a fixed phase interval. When the delay time of the multipath interference signal is between two specified phases, the correlation peak sidelobe interference will no longer be generated, thereby obtaining better multipath interference suppression performance. Compared with the conventional CSK/R-CSK modulation system with continuous phase configuration, the present invention can effectively suppress the multipath signal interference with the delay time between the specified phases, and improve the resolution of the receiver because the R-CSK modulation is used in the discontinuous configuration of the phases at equal intervals. Since the basic message and the extended message are respectively placed on the orthogonal IQ branches, different power ratios can be configured for the basic message signal and the extended message signal with different message rates, and the signal broadcasting efficiency is improved; The channels are orthogonal, and the carrier phase differs by 90 degrees, which can effectively avoid the influence of the high-power extended text signal on the receiving performance of the basic text signal; broadcast BPSK signals on the I branch, which can not only provide the Q branch with the synchronization required for CSK demodulation Since the basic message signal and the extended message signal have different spreading codes and the carrier is orthogonal, the system user who only needs to receive the basic message does not need to consider the existence of the extended message, which can simplify the design of the basic message receiver. Reduce the cost of basic text receivers. The method of the invention is suitable for the fields of communication, navigation system design and the like.

Description of drawings

Fig. 1 is the broadcast method block diagram in the teletext signal broadcast method based on phase discontinuous R-CSK modulation of the present invention;

Fig. 2 is the timing relation of each component of I branch baseband signal;

Fig. 3 is the timing relationship of each component of the Q branch baseband signal;

Fig. 4 is the constellation diagram of complex baseband signal;

Fig. 5 is the structure diagram of basic message signal receiver;

Fig. 6 is the structure diagram of the coherent receiver of the double-rate message signal;

Fig. 7 is the structure diagram of the non-coherent receiver of the double-rate message signal;

Fig. 8 is a comb filter composition diagram;

Fig. 9 is the principle block diagram of multipath interference signal formation;

Figure 10(a) is a diagram of the phase mapping relationship between conventional CSK/R-CSK modulation information and PRN code (the phase sequence is advanced);

Figure 10(b) is a diagram of the phase mapping relationship between conventional CSK/R-CSK modulation information and PRN code (phase sequence lag);

Figure 11 is a block diagram of the analysis of the influence mechanism of multipath signals;

Figure 12 is an analysis diagram of the influence of conventional CSK/R-CSK modulation multipath signals;

Fig. 13 is the theoretical bit error rate curve diagram of conventional CSK/R-CSK modulation in the presence or absence of multipath interference signals;

Fig. 14 is the phase non-continuous R-CSK modulation information and PRN code phase mapping relationship diagram proposed by the present invention;

15 is an analysis diagram of the influence of the phase discontinuous CSK/R-CSK modulation multipath signal proposed by the present invention;

Fig. 16 is the simulation effect comparison diagram of the information transmission bit error rate of the phase discontinuous R-CSK of the present invention and the conventional R-CSK information bit error rate under the multipath scenario;

FIG. 17 is a schematic block diagram of the phase discontinuous R-CSK demodulation matched filter circuit proposed by the present invention;

FIG. 18 is a schematic diagram of the composition and structure of an apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation according to an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

The present invention's teletext signal broadcasting method based on phase discontinuous R-CSK modulation, in practical application, as shown in Figure 1, applies IQ two-way quadrature modulation to realize double-rate composite teletext signal broadcasting.

Modulate the basic message on the in-phase I branch, perform BPSK-DSSS direct-sequence spread spectrum on the basic message, and construct the in-phase I branch baseband signal;

The extended message is modulated on the quadrature Q branch, and the phase non-continuous R-CSK-DSSS direct-sequence spread spectrum is performed on the extended message to construct the quadrature Q branch baseband signal; The modulation symbol determines a pseudo-random spread spectrum sequence, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence, and the fixed phase interval is at least greater than one The chip phase of the pseudo-random spread spectrum sequence, that is, the phase interval between the initial phases (chip units) of the pseudo-random spread spectrum sequence corresponding to two adjacent modulation symbols of any value is a fixed value and differs by two chips above;

The construction of the in-phase I-branch baseband signal and the quadrature Q-branch baseband signal is implemented according to the following methods respectively.

Among them, for the construction of the in-phase I branch baseband signal, the specific method is as follows:

Channel coding is performed on the basic message to obtain the coded bit stream _DB (t);

According to the basic message spreading code periodic clock and Chip clock provided by the timing generator, the basic message spreading code _{C B} (t) is generated by the basic message spreading code generator. t) perform BPSK-DSSS direct-sequence spread spectrum modulation, and update the corresponding bit stream of the basic message as C _B (t) D _B (t);

As shown in Figure 2, the timing relationship of each component of the in-phase I branch baseband signal is given. The basic message clock time length is T _BS =1ms, and the information of the basic message is grouped and channel coded to form a rate R _B =1/ T _BS = ₁ kbps, bit stream DB (t) of plus or minus 1. The code rate of the basic message spreading code C _B (t) is 10.23MHz, the basic message spreading code cycle time length T _BC =1ms, and the value is plus or minus 1. The correspondence between the message and the pseudo-random sequence is 1->"PRN(0)+",-1->"PRN(0)-", where "PRN(0)+" represents a positive-polarity pseudo-random with an initial phase of 0 Random sequence, "PRN(0)-" represents a negative-polarity pseudo-random sequence with an initial phase of 0.

Based on the power ratio coefficient A _I of the preset basic message, the in _- phase I branch baseband signal S _I (t) is obtained according to S _I (t)=A _I ·C _B (t)·DB (t).

For the construction of the quadrature Q branch baseband signal, the specific method is as follows:

Channel coding is performed on the extended message to obtain the coded bit stream;

According to the extended message symbol clock provided by the timing generator, 1->K _R bit serial/parallel conversion is performed on the corresponding bit stream after extended message encoding to obtain a parallel data stream; the duration of each K _R bit of parallel data is the symbol time. The length is equal to N times the cycle time of the spreading code of the extended message;

配置的相位间隔为Z，其中Z为大于1的整数。则并行数据流所对应的相位偏移量

其中i＝0,1,…,M-1，Z与M满足M*Z≤L的约束；According to the extended message spread spectrum code periodic clock provided by the timing generator (referred to as the extended message code periodic clock in FIG. 1 for short), the phase selection module generates the phase corresponding to the parallel data stream according to the preset phase equal interval non-continuous mapping relationship Offset. Here, let the period length of the spread spectrum code of the spread message be L chips, the information symbols K _R bits and the corresponding number of information symbols are

The configured phase interval is Z, where Z is an integer greater than 1. Then the phase offset corresponding to the parallel data stream

where i=0,1,...,M-1, Z and M satisfy the constraint of M*Z≤L;

Figure 3 shows the timing relationship of each component of the quadrature Q branch signal. The extended message symbol clock time length _{TES, R} is equal to N times the extended message spreading code cycle clock time length _TEC , and K _R bit is used to represent a symbol , the broadcast rate of extended message information R _E =K _R / _TES,R . Without loss of generality, for the convenience of the subsequent description, set the time length of the extended message spread spectrum code cycle clock T _EC =1ms, repeat the phase shift 2 times (N=2), the extended message symbol clock time length T _ES,R =2ms, 6bit is used to represent a symbol (K _R =6), the value range of the message is 0～63, the phase interval Z=64 chips, and the corresponding phase offset is 64*i, i=0,1,...,63, Then the broadcast rate of the extended message information is RE, _R = 6/TES, _R = 3kbps, and two identical pseudo-random sequences are repeatedly modulated with the same phase (that is, the 6-bit message (i) in Figure 3 and the N PRNs (i* Z) corresponds to), connect two pseudo-random sequences with the same phase offset in sequence to form a new modulation symbol, and complete the phase-equidistant non-continuous configuration code shift keying modulation with repeated phase shifts for many times. The correspondence between the 6-bit message (i) and the PRN (i*Z) in FIG. 3 is only an embodiment of the present invention, and other correspondences are also possible.

并结合预设扩展电文功率配比系数A_Q，按

获得伪随机扩频序列S_Q(t)，即正交Q支路基带信号S_Q(t)，其中，伪随机扩频序列的码相位受扩展电文控制。According to the extended message code cycle clock, the chip clock, and the phase offset corresponding to the parallel data stream provided by the timing generator, the extended message spread spectrum code generator generates the extended message spread spectrum code, and based on the extended message spread spectrum code The code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-consecutive configuration code shift keying modulation is performed to obtain the modulated spread text spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

A pseudo-random spreading sequence S _Q (t) is obtained, that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message.

(A _I ) ² +(A _Q ) ² =1

时，复数基带信号的星座图，这里只给出了一个示例，功率配比关系不限于此对应关系。As shown in Figure 4, it is given when setting

When , the constellation diagram of the complex baseband signal, only an example is given here, and the power ratio relationship is not limited to this corresponding relationship.

In the embodiment of the present application, when the phase-equi-spaced discontinuous configuration code shift keying modulation is not repeated based on the spread spectrum code of the spread message, this modulation method is CSK modulation.

其中

为信号发射端按照预设的相位映射关系设置的码相位。当多径干扰信号的延迟时间超出1个扩频码码片、且小于Z-1个码片时，多径干扰信号的码相位将不会与预设的任何码相位相同，也就不会在接收机CSK/R-CSK信号解调输出端产生任何相关峰旁瓣干扰。例如，扩频码码片时间为1微秒时，相位间隔设置为64的CSK/R-CSK调制信号将不受延迟路径为30～1890米的多径干扰信号影响。相位间隔Z越大，可抑制的多径干扰信号延迟范围越广，在M*Z≤L不等式的约束下，等间隔相位配置可以获得最大的多径干扰信号延迟抑制范围。In this example of the invention, the phase interval Z is an integer greater than one. Let the delay time of the multipath interference signal be τ _m (chip unit), then the code phase of the multipath interference signal is

in

The code phase set by the signal transmitter according to the preset phase mapping relationship. When the delay time of the multipath interference signal exceeds 1 spread spectrum code chip and is less than Z-1 chips, the code phase of the multipath interference signal will not be the same as any preset code phase, and it will not be Any correlation peak sidelobe interference is generated at the receiver CSK/R-CSK signal demodulation output. For example, when the chip time of the spreading code is 1 microsecond, the CSK/R-CSK modulated signal whose phase interval is set to 64 will not be affected by the multipath interference signal whose delay path is 30 to 1890 meters. The larger the phase interval Z is, the wider the suppressable multipath interference signal delay range is. Under the constraint of the M*Z≤L inequality, the equal-spaced phase configuration can obtain the largest multipath interference signal delay suppression range.

In this example of the present invention, regardless of the channel coding difference between the basic message and the extended message, in order to ensure that the same message demodulation performance is obtained at the receiving end, a branch with a higher message rate is generally configured with a higher signal broadcasting power .

The two branches use different spreading code sequences. When the message rates are different, the IQ branch can allocate different transmit powers, so that the basic message and the extended message received by the receiver have the same receiving performance. The spreading codes and telegrams of the two channels of the broadcast signal IQ are kept in sync with each other.

Then the complex expressions for the in-phase I branch baseband signal S _I (t) and the quadrature Q branch baseband signal S _Q (t) are as follows:

S(t)=S _I (t)+jS _Q (t)

where j is an imaginary number.

Then, for the in-phase I branch baseband signal and the quadrature Q branch baseband signal, perform IQ quadrature modulation to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain a radio frequency carrier signal, and finally undergo power amplification processing to form The double-rate composite text signal is handed over to the transmitting antenna for broadcasting.

Here, the RF transmission signal of the dual-rate composite text signal is expressed as follows:

Among them, P _s represents the total power of the radio frequency signal transmission of the composite text, and f _c represents the frequency of the transmitted signal.

In the teletext signal broadcasting method based on the phase discontinuous R-CSK modulation designed by the present invention, the basic telegram and the extended telegram are respectively placed on the orthogonal IQ branches, and to increase the broadcasting rate of the expanded telegram, only the power of the expanded telegram signal needs to be increased, The efficiency of signal broadcasting is improved; the IQ branches are orthogonal, and the carrier phase differs by 90 degrees, which can effectively avoid the influence of the high-power extended text signal on the receiving performance of the basic text signal; the BPSK signal broadcast on the I branch can be used for the Q branch. It can provide the synchronization information required for CSK demodulation, and can effectively broadcast the basic message; the use of multiple repetitions, or zero repetitions, i.e. non-repetitive phase shift, phase-equidistant configuration code shift keying modulation technology, can effectively improve information The broadcast rate further improves the signal broadcast efficiency and effectively suppresses multipath interference signals.

Aiming at the above designed method for broadcasting a message signal based on phase discontinuous R-CSK modulation, the present invention further designs a double-rate message signal receiving method, including a basic message receiving method, an extended message receiving method based on a phase discontinuous R-CSK modulated message signal A telegram coherent demodulation receiving method and an extended telegram non-coherent demodulation receiving method; wherein, the basic telegram receiving method, as shown in Figure 5, is as follows:

The RF carrier signal received by the receiver antenna is processed by the RF Front-End to output a digital intermediate frequency signal; the digital intermediate frequency signal is first mixed with the carrier copied by the carrier ring to output an orthogonal IQ two-way baseband signal, and the IQ two-way baseband signal Perform correlation operations with the basic message spread spectrum code copied by the basic message spread spectrum code generator to obtain two IQ correlation results; then, the two IQ correlation results are used as the input of the phase detection filter module, and the phase detection filter module calculates the carrier phase detection. Error and code phase detection error, and filter the phase detection error. The filtering results are used to adjust the carrier NCO (Carrier NCO) and the code NCO (Code NCO) respectively, so that the carrier output by the Carrier NCO is consistent with the received carrier. The basic message spreading code copied by the basic message spreading code generator under the control of Code NCO is consistent with the basic message spreading code received, which ensures that the carrier and spreading code in the received signal at the next moment are still completely detected in the tracking loop. At the same time, the correlation result output by the I branch correlator is judged by the basic message judgment module to output the basic message data bits.

The coherent demodulation and reception method of the extended message in the message signal modulated by the phase discontinuous R-CSK is shown in Figure 6, and the details are as follows:

When demodulating the basic message, the extended message spread spectrum code cycle clock and Chip clock obtained after synchronization are transmitted to the extended message spread spectrum code generator and the coherent matched filter module, and the extended message symbol clock and the extended message The spread spectrum code cycle clock is transmitted to the comb filter; the Q branch baseband signal is transmitted to the comb filter, and the comb filter superimposes N groups of pseudo-random sequence data in the same symbol into one group of pseudo-random sequence data;

Among them, the block diagram of the comb filter is shown in Figure 8: under the control of the extended message spreading code cycle clock, the comb filter sequentially delays the input data N-1 times, and each time delay extends the message spreading code The cycle time is _TEC seconds, and then the N-1 time delay data is superimposed with the input data and sent to the data interception module; secondly, the data interception module intercepts the input under the control of the extended message symbol clock and the extended message spread spectrum code cycle clock. The data stream outputs the data superimposed N times in the same symbol, and the data time length is the cycle time _TEC seconds of the spread spectrum code of the extended message. The intercepted data is sent to the coherent matched filtering module.

Then, under the control of the extended message symbol clock and the extended message spreading code cycle clock, the coherent matched filtering module connects the received data block with the time length of _TEC to the extended message spreading code generator in the extended message spreading code cycle. The clock and the extended message spread spectrum code generated under the control of the chip clock perform correlation matching calculation, and the correlation result is output to the correlation peak search module to search for the phase of the local extended message spread spectrum code corresponding to the correlation peak, and convert the phase to bit data output;

Finally, the bit data output by the correlation peak search module is passed through the channel decoding module to obtain the transmitted extended message data.

The non-coherent demodulation and reception method of the extended message in the message signal based on the phase discontinuous R-CSK modulation is shown in Figure 7, and the details are as follows:

When demodulating the basic message, the extended message spread spectrum code cycle clock and Chip clock obtained after synchronization are transmitted to the extended message spread spectrum code generator and the non-coherent matched filter module, and the extended message symbol clock and the extended message The period clock of the message spread spectrum code is transmitted to the comb filter; the baseband IQ two-way signal is transmitted to the comb filter, and the comb filter superimposes N groups of pseudo-random sequence data in the same symbol into one group of pseudo-random sequence data;

Among them, the block diagram of the comb filter is shown in Figure 8: under the control of the extended message spreading code cycle clock, the comb filter sequentially delays the input data N-1 times, and each time delay extends the message spreading code The cycle time is _TEC seconds, and then the N-1 time delay data is superimposed with the input data and sent to the data interception module; secondly, the data interception module intercepts the input under the control of the extended message symbol clock and the extended message spread spectrum code cycle clock. The data stream outputs the data superimposed N times in the same symbol, and the data time length is the cycle time _TEC seconds of the spread spectrum code of the extended message. The intercepted data is fed to the incoherent matched filter module.

Then, under the control of the extended message symbol clock and the extended message spreading code cycle clock, the incoherent matched filtering module combines the received data block with the time length of _TEC with the extended message spreading code generator in the extended message spreading code generator. The periodic clock and the spread spectrum code generated under the control of the chip clock perform correlation matching calculation, and the correlation result is output to the correlation peak search module to search for the phase of the local spread spectrum code corresponding to the correlation peak, and convert the phase to bit data output;

Finally, the bit data output by the correlation peak search module is passed through the channel decoding module to obtain the transmitted extended message data.

Figure 9 shows the principle block diagram of the formation of multipath interference signals. Usually, during the working process of the receiver, in addition to receiving the direct signal transmitted by the satellite, it will also receive the same satellite reflected by other objects (such as buildings, etc.) at the same time. The transmitted signal is the multipath signal. Assuming that the satellite signal transmission time is t ₀ , the time t ₁ when the receiver receives the direct signal should be equal to the signal transmission time t ₀ plus the signal propagation time delay τ ₁ , that is, t ₁ =t ₀ +τ ₁ , the receiver receives more The time t ₂ of the path signal is equal to the signal transmission time t ₀ plus the propagation time delay τ ₂ of the signal reaching the building and the propagation time delay τ ₃ from the building to the receiver, ie t ₂ =t ₀ +τ ₂ +τ ₃ . Obviously, the time delay of the multipath signal reaching the receiver is longer than that of the direct signal, and the power of the multipath signal is weaker than that of the direct signal due to reflection loss and space propagation loss.

Conventional CSK/R-CSK modulation generally adopts the phase sequence advance or phase sequence lag mode, assigns different PRN phases to the modulation information symbols one by one, and maps the modulation information to a continuous phase region of the PRN code, Figure 10(a) And Fig. 10(b) takes CSK(6) as an example, and gives the phase mapping relationship diagrams of the phase sequence advance and the phase sequence lag, respectively.

When there is multipath interference, the multipath signal with an integer chip time delay is likely to cause a large correlation peak sidelobe at the output of the CSK/R-CSK signal demodulator, which interferes with the CSK/R-CSK demodulation decision. Increase the CSK/R-CSK demodulation bit error rate. Taking the conventional CSK/R-CSK modulation information and PRN code phase mapping diagram (phase sequence advance) shown in Figure 10(a) as an example, for CSK(6) modulation, the modulation information is 30, and the multipath time delay is 5 The multipath signal power is attenuated by 3dB compared to the direct signal, and the phase difference from the direct signal carrier is 0 degrees. Figure 11 shows the analysis diagram of the multipath influence mechanism under the above simulation conditions. The multipath signal delay is consistent with the mapping phase of the modulation information 25. In addition to the correlation peak formed by the direct signal at the CSK/R-CSK signal demodulation output end, there are also large correlation peak side lobes formed by the multipath signal. This will seriously interfere with the CSK/R-CSK demodulation decision.

Multipath signals with different chip delays also have different effects on different modulation information symbols. Also taking the conventional CSK/R-CSK modulation information and PRN code phase mapping relationship diagram (phase sequence advance) shown in Figure 10(a) as an example, for CSK(6) modulation, when the modulation message is 0, because there will be no There is a large correlation peak side lobe formed by the multipath signal, so it will not be affected by the multipath signal, as shown in Figure 12(a); when the modulation message is 30, the time delay of the multipath signal is 1 ~ When there are 30 chips, there will be large correlation peak side lobes formed by the multipath signal, so it will be affected by the multipath signal with a time delay of 1 to 30 chips, as shown in Figure 12(b) ; When the modulation message is 63, when the time delay of the multipath signal is 1 to 63 chips, there will be a large correlation peak sidelobe formed by the multipath signal, so the time delay will be 1 to 63 chips. The influence of the multipath signal of the chip is shown in Figure 12(c). It can also be seen from Figure 12 that the conventional CSK(6) modulated signal will be affected by the multipath signal with a time delay of 1 to 63 chips. When When the time delay of the multipath signal is greater than 63 chips, since there is no mapping phase of the modulation information within this delay range, the correlation value interference caused by the multipath signal will not be generated, so it will not be affected by the multipath signal. influences.

From the perspective of demodulation bit error rate, it can be more intuitively explained that conventional CSK/R-CSK modulation is affected by multipath interference, and theoretically calculate the bit error rate performance of CSK/R-CSK when multipath interference signals exist or not. , the relevant symbols and corresponding relationship conventions are as follows:

When there is no multipath interference, the formula for calculating the bit error rate of the coherent demodulation symbol of conventional CSK/R-CSK modulation is as follows:

Wherein, E _s /N ₀ =E _b /N ₀ ×K=E _b /N ₀ ×log ₂ M, K is the number of bits per symbol, and the system M=2 ^K .

The formula converted to the information bit error rate is as follows:

During CSK/R-CSK demodulation, due to the existence of multipath interference signals with integer chip delay, during matched filtering, the multipath signals will form a larger correlation value output R _M , which is set to the maximum correlation peak value R _max The ratio is μ, and the size of μ is affected by the carrier phase, the delay of the multipath signal and the power of the multipath signal. In the presence of multipath interference, the formula for calculating the bit error rate of the coherent demodulated symbols of conventional CSK/R-CSK modulation is as follows:

The formula converted to the information bit error rate is as follows:

Figure 13 shows the theoretical bit error rate curve of conventional CSK/R-CSK modulation information transmission when multipath interference signals exist or not, in which the curve "theoretical-conventional CSK/R-CSK-no multipath" is no more The coherent demodulation bit error rate curve when the path signal is obtained; "theory-conventional CSK/R-CSK-multipath" means that the presence power is attenuated by 3dB compared with the direct signal, the delay time is an integer number of chips (within the range of phase mapping), and the The coherent demodulation bit error rate curve of the multipath signal with the direct signal carrier phase difference of 0 degrees (ie μ=0.707). It can be clearly seen from Figure 13 that when multipath interference exists, the coherent demodulation bit error rate is significantly higher than when there is no multipath interference.

Figure 14 shows one of the phase non-continuous R-CSK modulation information proposed by the present invention and a PRN code phase mapping diagram. Taking CSK(6) modulation as an example, assuming that the phase interval Z=64 and the information symbol i takes a value from 0 to 63, the initial phase of the corresponding spreading code is PRN(i*Z).

In order to more intuitively reflect the effectiveness of the phase discontinuous CSK/R-CSK modulation proposed by the present invention relative to the conventional CSK/R-CSK modulation, the analysis is still made from two aspects of correlation peak side lobes and demodulation bit error rate.

Taking CSK(6) as an example, using the phase discontinuous method proposed by the present invention, for the modulation information symbol of 30, the multipath time delay of 1 to 256 chips, the multipath signal power is attenuated by 3dB compared with the direct signal, and the direct signal carrier The case where the phase difference is 0 degrees is simulated. In order to facilitate the simulation, an equally spaced phase configuration with a phase interval Z=64 is adopted here. The analysis of the influence of the phase discontinuous CSK/R-CSK modulation multipath signal proposed by the present invention is shown in Fig. 15 . It can be seen from the figure that when the multipath delay time is greater than or equal to 1 chip and less than or equal to 63 chips, since there is no mapping phase of the modulation information within this delay range, the correlation value caused by the multipath signal will not be generated. Therefore, it will not be affected by multipath signals in this range. When the chip time of the spread spectrum code is 1 microsecond, this delay time corresponds to the range of 30 to 1890 meters. When the multipath delay time is greater than or equal to 64 chips, although it will still be interfered by the correlation value caused by the multipath signal, it only occurs when the multipath time delay is an integer multiple of the phase interval Z=64 chips. Dispersion is obtained, ie only affected by integer-chip multipath signals whose time delay is the phase interval Z. And with the increase of the time delay of the multipath signal, the signal power gradually weakens, and the influence of the multipath signal with the time delay greater than 63 chips is very small, so the phase discontinuous CSK/R-CSK modulation of the present invention can effectively suppress the multipath signal. influence of interference signals.

Also from the demodulation error rate, the effectiveness of the phase discontinuous R-CSK modulation proposed by the present invention in suppressing multipath interference can be more intuitively illustrated than the conventional CSK/R-CSK modulation. For the convenience of simulation calculation and without loss of generality, taking R-CSK(6,2) as an example, for the equally spaced phase discontinuous configuration with the phase interval Z=64, the multipath delay time is 1 chip, and the multipath delay time is 1 chip. The signal power is attenuated by 3dB compared with the direct signal, and the phase difference with the direct signal carrier is 0 degrees. In this multipath scenario, the comparison diagram of the simulation effect of the information transmission bit error rate of the phase discontinuous R-CSK of the present invention and the conventional R-CSK information bit error rate is shown in FIG. 16 . It can be seen that in the presence of 1-chip multipath interference, the information transmission bit error rate of the phase discontinuous R-CSK of the present invention is basically consistent with the theoretical curve, which is obviously better than that of conventional R-CSK modulation.

In addition, FIG. 17 shows a schematic block diagram of a demodulation matched filter circuit for phase discontinuous R-CSK modulation proposed by the present invention. Compared with conventional CSK/R-CSK modulation, the phase discontinuous R-CSK modulation proposed by the present invention CSK modulation hardly increases the computational cost of signal demodulation.

FIG. 18 is a schematic diagram of the composition and structure of an apparatus for broadcasting a text signal based on phase discontinuous R-CSK modulation according to an embodiment of the present invention. As shown in FIG. 18 , the apparatus for broadcasting a text signal based on phase discontinuous R-CSK modulation according to an embodiment of the present invention ,include:

The first modulation unit 180 is configured to modulate the basic message on the in-phase I branch, perform BPSK-DSSS direct-sequence spread spectrum on the basic message, and construct the in-phase I branch baseband signal;

The second modulation unit 181 is configured to modulate the extended message on the quadrature Q branch, perform phase non-continuous R-CSK-DSSS direct-sequence spread spectrum on the extended message, and construct the quadrature Q branch baseband signal; During modulation, a pseudo-random spread spectrum sequence is determined for each symbol to be modulated, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence. The fixed phase interval is at least greater than the chip phase of a pseudorandom spread spectrum sequence, that is, the phase interval between the initial phases (chip units) of the pseudorandom spread spectrum sequence corresponding to two adjacent modulation symbols of any numerical value is fixed value, and the difference is more than two chips;

The carrier modulation unit 182 is used to perform IQ quadrature modulation on the basic teletext baseband signal of the in-phase I branch and the extended teletext baseband signal of the quadrature Q branch to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain RF carrier signal;

The sending unit 183 is configured to perform power amplifying processing on the radio frequency carrier signal to form a double-rate composite message signal for broadcasting.

As a preferred technical solution of the present invention: assuming that the phase interval is Z, when any value in the to-be-modulated message is expressed as i, the initial phase of the pseudo-random spread spectrum sequence is PRN(i*Z); i= 0～M-1, M is the number of information symbols of the message to be modulated, and the value of Z is greater than or equal to 2 chips and M*Z is less than or equal to the number of chips corresponding to a pseudo-random spread spectrum sequence period.

As a preferred technical solution of the present invention, in the apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation in the embodiment of the present invention, the first modulation unit 180 includes:

_A coding subunit, used for channel coding the basic message to obtain the coded bit stream DB (t);

The first spread spectrum modulation subunit is used for generating the basic message spread spectrum code C _B (t) from the basic message spread spectrum code generator according to the basic message spread spectrum code periodic clock and the Chip clock provided by the timing generator, and for all The bit stream DB (t) corresponding to the basic message is obtained and subjected to BPSK-DSSS direct-sequence spread spectrum modulation, and the bit stream corresponding to the updated basic message is C _B (t) _{D B (} t);

The baseband signal generation subunit is used to obtain the baseband signal of the in-phase I branch according to S _I (t)=A _I C _B (t) D _B (t) based on the power ratio coefficient A _I of the preset basic message S _I (t);

As a preferred technical solution of the present invention, in the apparatus for broadcasting a message signal based on phase discontinuous R-CSK modulation in the embodiment of the present invention, the second modulation unit 181 includes:

an encoding subunit, used to perform channel encoding on the extended telegram to obtain an encoded bit stream;

The serial/parallel conversion subunit is used to perform 1->K _R bit serial/parallel conversion on the corresponding bit stream encoded by the extended message according to the extended message symbol clock provided by the timing generator to obtain a parallel data stream; in which every K _R The duration of bit parallel data, that is, the symbol time length is equal to N times the cycle time of the spreading code of the spread message;

The phase offset subunit is used to generate the phase offset corresponding to the parallel data stream by the phase selection module according to the preset phase equal interval non-continuous mapping relationship according to the extended message spread spectrum code periodic clock provided by the timing generator;

并结合预设扩展电文功率配比系数A_Q，按

获得伪随机扩频序列S_Q(t)，即正交Q支路基带信号S_Q(t)，其中，伪随机扩频序列的码相位受扩展电文控制，(A_I)²+(A_Q)²＝1。The second spread spectrum modulation subunit is used to generate the spread spectrum code of the spread telegram according to the period clock of the spread telegram code, the chip clock and the phase offset corresponding to the parallel data stream provided by the timing generator, and based on the spread telegram The spread spectrum code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-continuous configuration code shift keying modulation is performed to obtain the modulated spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

Obtain the pseudo-random spreading sequence S _Q (t), that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message, (A _I ) ² +(A _Q ) ² = 1.

As a preferred technical solution of the present invention, the extended electronic text symbol clock is an integer multiple of the extended electronic text code period clock, and is synchronized with the extended electronic text code period clock.

In the embodiment of the present application, when the phase-equi-spaced discontinuous configuration code shift keying modulation is not repeated based on the spread spectrum code of the spread message, this modulation method is CSK modulation.

Compared with the prior art, the teletext signal broadcasting method based on phase discontinuous R-CSK modulation of the present invention has the following excellent effects:

The method for broadcasting a message signal based on phase discontinuous R-CSK modulation of the present invention adopts IQ two-way quadrature modulation, wherein the in-phase I branch adopts BPSK binary phase shift keying carrier modulation, and the baseband signal is DSSS direct sequence spread spectrum. Basic message; BPSK binary phase shift keying carrier modulation is used on the quadrature Q branch, and the baseband signal is a pseudo-random pseudo-random configuration code shift keying modulation with equal intervals of phase that is repeated for many times, or repeated zero times, that is, the phase shift is not repeated. Spread spectrum sequence, the code phase of the pseudo-random sequence is controlled by the broadcast spread message; under the condition of the same spread spectrum code length or period, the CSK modulation method can be used to obtain a higher message broadcast rate than DSSS direct sequence spread spectrum; Compared with the conventional CSK modulation system, the invention can effectively improve the demodulation performance of the receiver under the condition that the effective information rate of broadcast is the same because the code shift keying modulation with repeated phase shift is adopted; it can improve the transmission of CSK modulation information. At the same time, the signal power density of the receiving end is kept unchanged, and the software and hardware cost and power consumption of the demodulation of the CSK message at the receiving end are avoided to be greatly increased; , which differ from each other by a fixed phase interval. When the delay time of the multipath interference signal is between two specified phases, the correlation peak sidelobe interference will no longer be generated, so as to obtain better multipath interference suppression performance; the present invention adopts the discontinuous configuration of R at equal intervals of the phases. -CSK modulation, compared with the conventional phase continuous configuration CSK/R-CSK modulation system, it can effectively suppress the multipath signal interference with the delay time between the specified phases, and improve the demodulation performance of the receiver; The telegrams are respectively placed on the orthogonal IQ branches, and different power ratios can be configured for the basic telegram signals and the extended telegram signals with different telegram rates, which improves the signal broadcasting efficiency; Effectively avoid the influence of high-power extended message signal on the reception performance of basic message signal; broadcast BPSK signal on the I branch, not only can provide the synchronization information required for CSK demodulation for the Q branch, but also effectively broadcast the basic message; The spread spectrum code of the teletext signal is different from that of the extended telegram signal and the carrier is orthogonal. The system user who only needs to receive the basic telegram does not need to consider the existence of the extended telegram, which can simplify the design of the basic telegram receiver and reduce the cost of the basic telegram receiver. The method of the invention is suitable for the fields of communication, navigation system design and the like.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and can also be made within the scope of knowledge possessed by those of ordinary skill in the art without departing from the purpose of the present invention. Various changes.

Claims (10)

1. a teletext signal broadcasting method based on phase discontinuous R-CSK modulation, is characterized in that: described method comprises: Modulate the basic message on the in-phase I branch, perform BPSK-DSSS direct-sequence spread spectrum on the basic message, and construct the in-phase I branch baseband signal; The extended message is modulated on the quadrature Q branch, and the phase non-continuous R-CSK-DSSS direct-sequence spread spectrum is performed on the extended message to construct the quadrature Q branch baseband signal; The modulation symbol determines a pseudo-random spread spectrum sequence, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence, and the fixed phase interval is at least greater than one The chip phase of the pseudorandom spread spectrum sequence, that is, the phase interval between the initial phases of the pseudorandom spread spectrum sequence corresponding to two adjacent modulation symbols of any numerical value is a fixed value, and the difference is more than two chips; Perform IQ quadrature modulation on the basic teletext baseband signal of the in-phase I branch and the extended teletext baseband signal of the quadrature Q branch to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain a radio frequency carrier signal. Amplify and process to form a double-rate composite message signal, which is handed over to the transmitting antenna for broadcast. 2. the teletext signal broadcasting method based on phase discontinuous R-CSK modulation according to claim 1, is characterized in that: The phase interval is Z, and when any value in the to-be-modulated message is expressed as i, the initial phase of the pseudo-random spread spectrum sequence is PRN(i*Z); i=0～M-1, M is the to-be-modulated message The number of modulation message information symbols, the value of Z is greater than or equal to 2 chips and M*Z is less than or equal to the number of chips corresponding to a pseudo-random spread spectrum sequence period. 3. the teletext signal broadcasting method based on phase discontinuous R-CSK modulation according to claim 1 and 2, is characterized in that: described constructing in-phase I branch baseband signal, comprises: Channel coding is performed on the basic message to obtain the coded bit stream _DB (t); According to the basic message spreading code periodic clock and Chip clock provided by the timing generator, the basic message spreading code _{C B} (t) is generated by the basic message spreading code generator. t) perform BPSK-DSSS direct-sequence spread spectrum modulation, and update the corresponding bit stream of the basic message as C _B (t) D _B (t); Based on the power ratio coefficient A _I of the preset basic message, the in _- phase I branch baseband signal S _I (t) is obtained according to S _I (t)=A _I ·C _B (t)·DB (t). 4. The teletext signal broadcasting method based on phase discontinuous R-CSK modulation according to claim 1 or 2, wherein the construction of the quadrature Q branch baseband signal comprises: Channel coding is performed on the extended message to obtain the coded bit stream; According to the extended message symbol clock provided by the timing generator, 1->K _R bit serial/parallel conversion is performed on the corresponding bit stream after extended message encoding to obtain a parallel data stream; the duration of each K _R bit of parallel data is the symbol time. The length is equal to N times the cycle time of the spreading code of the extended message; According to the extended message spread spectrum code periodic clock provided by the timing generator, the phase selection module generates the phase offset corresponding to the parallel data stream according to the preset phase equal interval non-continuous mapping relationship; According to the extended message code cycle clock, the chip clock, and the phase offset corresponding to the parallel data stream provided by the timing generator, the extended message spread spectrum code generator generates the extended message spread spectrum code, and based on the extended message spread spectrum code The code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-consecutive configuration code shift keying modulation is performed to obtain the modulated spread text spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

Obtain the pseudo-random spreading sequence S _Q (t), that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message, (A _I ) ² +(A _Q ) ² = 1. 5. the teletext signal broadcasting method based on phase discontinuous R-CSK modulation according to claim 1 and 2, it is characterized in that: described extended teletext symbol clock is an integer multiple of the extended teletext code cycle clock, and is combined with the extended teletext code Periodic clock synchronization. 6. A teletext signal broadcasting device based on phase discontinuous R-CSK modulation, it is characterized in that: described device comprises: The first modulation unit is used to modulate the basic message on the in-phase I branch, and perform BPSK-DSSS direct-sequence spread spectrum on the basic message to construct the in-phase I branch baseband signal; The second modulation unit is used to modulate the extended message on the quadrature Q branch, perform phase non-continuous R-CSK-DSSS direct-sequence spread spectrum on the extended message, and construct the quadrature Q branch baseband signal; During modulation, a pseudo-random spread spectrum sequence is determined for each symbol to be modulated, and a fixed phase interval is maintained between two adjacent symbols to be modulated by adopting a cyclic shift for the basic pseudo-random spread spectrum sequence. The fixed phase interval is at least greater than the chip phase of a pseudorandom spread spectrum sequence, that is, the phase interval between the initial phases of the pseudorandom spread spectrum sequence corresponding to two adjacent modulation symbols of any numerical value is a fixed value, and a difference of two chip or more; The carrier modulation unit is used to perform IQ quadrature modulation on the basic teletext baseband signal of the in-phase I branch and the extended teletext baseband signal of the quadrature Q branch to obtain an intermediate frequency carrier signal, and then perform up-conversion processing on the intermediate frequency carrier signal to obtain a radio frequency carrier signal; The sending unit is used to amplify the radio frequency carrier signal to form a double-rate composite message signal for broadcasting. 7. the teletext signal broadcasting device based on phase discontinuous R-CSK modulation according to claim 6, is characterized in that: The phase interval is Z, and when any value in the to-be-modulated message is expressed as i, the initial phase of the pseudo-random spread spectrum sequence is PRN(i*Z); i=0～M-1, M is the to-be-modulated message The number of modulation message information symbols, the value of Z is greater than or equal to 2 chips and M*Z is less than or equal to the number of chips corresponding to a pseudo-random spread spectrum sequence period. 8. The electronic text signal broadcasting device based on phase discontinuous R-CSK modulation according to claim 6 or 7, wherein the first modulation unit comprises: _A coding subunit, used for channel coding the basic message to obtain the coded bit stream DB (t); The first spread spectrum modulation subunit is used for generating the basic message spread spectrum code C _B (t) from the basic message spread spectrum code generator according to the basic message spread spectrum code periodic clock and the Chip clock provided by the timing generator, and for all The bit stream DB (t) corresponding to the basic message is obtained and subjected to BPSK-DSSS direct-sequence spread spectrum modulation, and the bit stream corresponding to the updated basic message is C _B (t) _{D B (} t); The baseband signal generation subunit is used to obtain the baseband signal of the in-phase I branch according to S _I (t)=A _I C _B (t) D _B (t) based on the power ratio coefficient A _I of the preset basic message S _I (t). 9. The electronic text signal broadcasting device based on phase discontinuous R-CSK modulation according to claim 6 or 7, wherein the second modulation unit comprises: an encoding subunit, used to perform channel encoding on the extended telegram to obtain an encoded bit stream; The serial/parallel conversion subunit is used to perform 1->K _R bit serial/parallel conversion on the corresponding bit stream encoded by the extended message according to the extended message symbol clock provided by the timing generator to obtain a parallel data stream; in which every K _R The duration of bit parallel data, that is, the symbol time length is equal to N times the cycle time of the spreading code of the spread message; The phase offset subunit is used to generate the phase offset corresponding to the parallel data stream by the phase selection module according to the preset phase equal interval non-continuous mapping relationship according to the extended message spread spectrum code periodic clock provided by the timing generator; The second spread spectrum modulation subunit is used to generate the spread spectrum code of the spread telegram according to the period clock of the spread telegram code, the chip clock and the phase offset corresponding to the parallel data stream provided by the timing generator, and based on the spread telegram The spread spectrum code is repeated many times, or repeated zero times, that is, the phase is not repeated, and the non-continuous configuration code shift keying modulation is performed to obtain the modulated spread spectrum code signal.

And combined with the preset extended telegram power ratio coefficient A _Q , press

Obtain the pseudo-random spreading sequence S _Q (t), that is, the quadrature Q branch baseband signal S _Q (t), wherein the code phase of the pseudo-random spreading sequence is controlled by the spreading message, (A _I ) ² +(A _Q ) ² = 1. 10. The teletext signal broadcasting device based on phase discontinuous R-CSK modulation according to claim 6 or 7, characterized in that: the extended teletext symbol clock is an integer multiple of the extended teletext code cycle clock, and is combined with the extended teletext code. Periodic clock synchronization.

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