Method of forming and processing the complex signal in the noise-the radio

 

The invention relates to the field of radio and can be used to improve structural secrecy of signals in noise-immune systems. The technical result is to increase the structural secrecy complex phase-shift keyed signals. The technical result is achieved by the fact that, on the transmission side perform phase shift keying carrier wave pseudo-random sequence and signal information at the receiving side the removal of the pseudorandom sequence with subsequent demodulation scheme Costas, and is characterized by the fact that, as a carrier wave using a modified bandpass noise, temporary sites with amplitude above the threshold have a uniform distribution of phases within the/2 relative phase of the reference frequency-modulated oscillations, and areas with amplitude below the threshold have the distribution phase, even within theand the handling of complex signal to produce a diagram of the Costas tracking imposed frequency modulation of the carrier. 5 Il.

The present invention otnositssya the radio.

To protect transmitted information on the following links need to be difficult or altogether exclude the possibility of selection of the modulating information signal potential razodrannom. The degree of protection of modulating the information signal is characterized by energy and structural secrecy of the transmitted radio signal as a whole.

To improve both energy and structural secrecy are complex photomanipulation signals (SFMS) [Interference protection radio systems with complex signals. Ed. by G. I. Tuzov. - M.: Radio and communication, 1985].

In practice, carrier and clock frequency SFMS have high stability. During the construction of M-phase signal with a sinusoidal carrier with frequency f0in the M-th power is formed coherent with the carrier sine wave at frequency Mf0. Dividing the frequency of this oscillation in M times, with a sufficiently large signal-to-noise ratio by the method of synchronous detection can be distinguished manipulating the sequence, and then the information signal. Thus, the use of a sinusoidal carrier does not allow to achieve high structural secrecy SFMS.

Closest to the proposed scheme and processing in the receiver, described, for example, in the book Varakin L. E. communication Systems with noise-like signals. M.: Radio and communication, 1985 on pages 16-17 and illustrated in Fig.1.7 and 1.8 adopted for the prototype.

In the transmitter a sequence of information symbols +1 and -1 is multiplied by the binary pseudo-random sequence (SRP), the elements of which also take values of1. Formed thus manipulating the sequence is multiplied by the sine wave carrier oscillation generated by the respective generator.

In the receiver SFMS is transferred to an intermediate frequency, is multiplied by the synchronous copy of the SRP, and then is demodulated, for example, a diagram of the Costas.

However, this method of forming SFMS does not exclude the intercept signal information razodrannom. So, manipulating the sequence can be distinguished by the scheme with Quad (scheme Pistohlkors), see, for example, in the book of Lindsay C. synchronization Systems in communication and control. TRANS. from English. M: Owls. radio, 1978, Fig.3.12. on page 101, or scheme Kostas shown there in Fig.3.13 on page 102. Then, based on the periodicity property of the SRP, you can select and signal information.

The proposed method allows p> To eliminate this drawback in the method of forming and processing of complex signals, comprising a transmitting-side phase shift keying carrier wave pseudo-random sequence and signal information at the receiving side the removal of the pseudo-random sequence with subsequent demodulation scheme Costas, as a carrier wave using a modified bandpass noise, temporary sites with amplitude above the threshold have a uniform distribution of phases within the/2 112125 relative phase of the reference frequency-modulated oscillations, and areas with amplitude below the threshold have the distribution phase, even within the. Moreover, the handling of complex signal to produce a diagram of the Costas tracking imposed frequency modulation of the carrier.

Let's call the modified bandpass noise quasi-noise carrier. Diagram of the device for implementing the method of forming SFMS with quasi-noise carrier shown in Fig.1, where 1 is the noise generator, 2 - band-pass filter, 3 - generator baseband signal, 4 - phase detector, 5 - reference generator Sinoe device, 91and 92the first and second keys, 10 - inverter (scheme), 111, 112and 113the first, second and third multiplier products, 12 - adder 13 - generator SRP.

The operation of the device is as follows. Blocks 1 and 2 form the original bandpass noiseblocks 3, 5 generates a reference sine wave, modulated by the frequency (phase):where Smod(t) is the modulating signal.

The output of the phase detector 4 produces a voltage U4(t)cos[W(t)-on(t)], and the output of the amplitude limiter 7If temporarily exclude from consideration the key 91at the output of the multiplier 111formed voltage

Thus, at the output of the multiplier 111the voltage vectorswill always be in the same half-plane (in-phase) (Fig. 2).

Key 91excludes from the output voltage of the multiplier 111temporary plots with small amplitudes. These sites bandpass noise with unit output 2 propuskaye threshold will have the distribution phase, uniform in the interval/2 relative phase of the reference oscillation, and lots of bandpass noise with amplitudes below the threshold will have a uniform distribution in the interval.
Thus formed Quisisana carrier inverse is manipulated in the multiplier 112binary sequence with1, formed by the multiplication of the SRP and signal information. As a result, the output of the multiplier 112formed SFMS with quasi-noise carrier. Stresses at various points of the circuit of Fig.1 shown in Fig.3.

In our receiver radio SRP is removed, and the outline of Costas comes Quisisana carrier, manipulated signal information. In the schema of the Costas PLL system averages the noise fluctuations of the phase and generates an oscillation similar to the reference sinusoidal oscillation at the output of block 5 in the transmitter (Fig. 1).

Frequency modulation of the reference oscillation is tracked by the PLL system similar to Doppler frequency shift. It is known [Digital systems of phase synchronization. Ed. by M. I. of Adissage. M: Owls. radio, 1980, page 166] that for tracking �602484.gif">Therefore, the introduction of frequency modulation of the carrier bottom limits the noise bandwidth of the system is the FAP, which dramatically reduces the sensitivity of razvetvlennykh.

Obviously, in the mode of synchronism when no signal information, the voltage at the input of the common mode filter of the channel most of the time (when the phase of the quasi-noise carrier is within the/2 will be positive. Computer simulation results confirm this conclusion. In Fig.4A shows the voltage at the output of the in-phase channel when no signal information. Information symbols having a relatively large duration of Tandwill release scheme Kostas correctly. In Fig.4B shows the signal at the filter output in-phase channel, and Fig.4B is the output of the integrator with a reset.

In razodrannye, built according to the scheme of Pistohlkors, a doubling of the frequency function of the phase distribution becomes uniform in the intervalthat indicates the absence of a spectral component at twice the frequency of the carrier (Fig. 5). Thus, a sinusoidal carrier even in the absence of manipulation is not allocated razvedriti schema valid input SFMS without removing the SRP. The duration element of the SRPemuch shorter than the duration information Tand:eTand. Band channel filters schemes Kostas razvetvlennykh must be at least 1/e, i.e. the selection of the elements of the SRP in razodrannye occurs at a much higher noise than the allocation information symbols in the receiver of our radio. Consequently, dramatically increases the probability of errors in demodulation elements SRP, especially for small values of the amplitude of the quasi-noise carrier (Fig.4D, e). In Fig.4D asterisks marked erroneously accepted items.

Thus, the use of quasi-noise bearing virtually eliminates the possibility of signal interception information potential razodrannom with a slight decrease noise immunity of the receiver of our radio and minimal hardware upgrade.


Claims

Method of forming and processing the complex signal in the noise of the radio, including on the transmission side phase shift keying carrier wave pseudo-random sequence by Asia in the scheme Costas, characterized in that as the carrier wave using a modified bandpass noise, temporary sites with amplitude above the threshold, have a uniform distribution of phases within the/2 112125 relative phase of the reference frequency-modulated oscillations, and areas with amplitude below the threshold have the distribution phase is uniform within theand the handling of complex signal to produce a diagram of the Costas tracking imposed frequency modulation of the carrier.

 

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