RU2002376C1 - Device for reception of signals with pseud0random retuning of working frequency of radio communication system - Google Patents

Description

the signal and interference mixture is fed to a frequency multiplier 8, where it is multiplied by the reference signals generated by the reference voltage generator 7. Moreover, the reference signal is transmitted directly to one multiplier 8, and to the other through the phase shifter 9 with a phase shift of / 2. The multiplication result is integrated by the integrator 10 and fed to the squares 11, and then to the adder 12. As a result, a voltage proportional to the square of the envelope of the cross-correlation function between the received and reference signals is generated at the output of the adder 12 of the 1st subchannel. At the output of adder 12 of the Pth subchannel, a voltage proportional to the variance of the interference acts. The voltage from the adders 12 through the square root calculators 13 is applied to the inputs of the multipliers 14, and then to the non-linear element 15, which implements a dependence of the form 1 ° (x), the zero-order Bessel function. From the output of the nonlinear voltage elements 15 in the form of a sequence of pulses with different amplitudes and periods equal to the duration of the element of the received signal To, are fed to the inputs of the voltage multipliers 16. The reset of the accumulated voltage in the voltage multipliers 16 to the inputs of the comparison device 17 the moment of the end of the information bit is ensured by supplying to the control inputs of the voltage multipliers 16 pulses from the second output of the synchronization device 18. Due to the operation of the search and synchronization device and 18 at the time of completion of the information bit at the output of the comparison device 17 as a result of comparing the voltages received at its inputs to the output voltage of the multipliers 16, a decision is di or d2 on the availability of a particular information symbol (1 or Q).

In order to obtain reliable estimates of the interference dispersion, the dispersion measurement takes place in frequency-channel free channels of the signal with frequency hopping at the moments, times preceding the appearance of signal elements at a particular operating frequency at the input of the device. To generate a voltage proportional to the estimation of the interference variance Ok2, there is a synthesizer 19, to which commands from the pseudo-random code generator 5 are given to turn on the frequency that will occur in the next frequency jump in accordance with the known effective code. If during the time (K - 2) then t (K - 1) then from the output of the frequency synthesizer 19 to one

the input of the mixer 20 received a voltage with a frequency of (mk + Afnp), where Dgpr is an intermediate frequency, and the signal and interference at a frequency fn and interference at a frequency Tk arrive at the second input of a mixer 20 during the same period of time, then as a result, at the output of the narrow-band filter 21 tuned to the frequency Afnp, the interference voltage acts in the form of a quasi-harmonic

fluctuations. Further, this voltage in squared 22 is squared and applied to the inputs of two parallel-connected integrators 23. The operation of the integrators 23 is provided by the control circuit 24, At times

supplying 24 pulses to the control input of the control circuit with a period To from the first output of the search and synchronization unit 18, the voltage is reset from one of the integrators 23, proportional to the interference power 6k2, to one of the inputs of the voltage divider 28 and zeroing this integrator. At the same time, the second integrator 23 enters the memory mode of the accumulated voltage

time That. As a result of the alternating operation of the integrators 23, a voltage proportional to OK is generated at the output of the control circuit 24 at each frequency jump. This voltage is output from the control circuit 24 to one of the inputs of the voltage divider 28.

From the outputs of the adders 12 of the 1st and 11th subchannels, the voltage is supplied to the inputs of the maximum selection device 25. Moreover, if at the input of the receiver 1, then from the output of the adder 12 of the 1st subchannel, the voltage proportional to the maximum of the envelope squared cross-correlation functions between

received and reference signals, and a voltage proportional to the variance of the noise is applied to the other input of block 25. When transmitting, O is the opposite. At the output of the maximum selection device 25

voltage proportional to the square of the signal amplitude estimate. The search and synchronization device 18 provides a voltage reset from block 25 after the end of the actions of each Kth signal element from the frequency hopper to the input of the square root calculator 26, the output of which produces a voltage proportional to the estimated amplitude of the Kth signal element Ak. This is the voltage through the multiplier by two 27

arrives at a voltage divider 28, the other input of which receives voltage from the output of the control circuit 24. As a result, at the output of the divider 28, a nonlinear weighting factor-DK Ak / ak2 is formed. A voltage proportional to / is supplied through the limiter 29 to the second inputs of the multipliers 14. In accordance with the values of the weighting factors in the multipliers 14, adaptive voltage control of each Kth element of the IFRF signal is applied to the other inputs of the multipliers 14.

The limiter 29 with the soft limit mode ensures the operation of the device in the absence of interference

Claims (1)

The claims A DEVICE FOR RECEIVING SIGNALS WITH A FULL-RANDOM CHANGE OF THE OPERATION FREQUENCY OF THE RADIO COMMUNICATION SYSTEMS, comprising a first quadrator and a first integrator connected in series, a maximum selection unit in series, a first square root calculator, two multiplier and a voltage divider, as well as a symmetrical and frequency of the processing channel, each of which includes two subchannels, each of which consists of a series-connected frequency multiplier, the second integrat and a second squarer, wherein the first inputs of the frequency multipliers are interconnected, and the second inputs of two frequency multipliers subchannels are connected to the output of the reference voltage generator directly and through a phase shifter, respectively, the other inputs of the second integrators of both subchannels are connected to each other and to the first output of the search and synchronization unit, the outputs of the second quadrants of both subchannels are connected to the corresponding inputs of the adder, the output of which is connected to the corresponding input of the block selecting a maximum and with the input of the second square root calculator, the output of which is connected to one of the inputs of the multiplier, characterized in that, for the purpose of To increase the noise immunity of receiving signals with pseudo-random frequency tuning, series-connected wide-band amplifier, a first frequency mixer, the other input of which is connected to the corresponding outputs of the pseudo-random code generator through the first frequency synthesizer, and the first band-pass filter, sequentially connected an additional integrator and a control unit are introduced into it (or its very small value) in one or another frequency channel. In this case, when the weighting factor exceeds a certain value, a constant voltage proportional to the limit threshold level is applied to the inputs of the multipliers 14 of the 1st and 1st subchannels from the limiter 29. (56) Zinchuk V.M. et al., Analysis of algorithms for 0-discrimination of signals with intra-bit pseudo-random frequency tuning. Communication Technology, Series Radio Communication Technology, vol. 7, 1989, p. 3-20. 5 neither, nor a limiter, moreover, each of the two symmetric and frequency-spaced channels includes a second frequency mixer connected in series, the other input of which is connected to the output of the second frequency synthesizer, and a band-pass filter, as well as a non-linear element and a voltage multiplier connected in series , 25 wherein the output of the broadband amplifier is connected to the corresponding inputs of the second frequency mixers of both symmetric and frequency-spaced channels, in each of which a second band 30 the filter is connected to the interconnected first inputs of the frequency multipliers, the output of the multiplier is connected to the input of a nonlinear element, the output of the voltage multiplier is connected to 35 by the corresponding input of the comparison unit, the inputs of the second frequency synthesizer are connected to the corresponding outputs of the pseudo-random code generator, the other input of the multiplier is connected through the organizer to the output of the voltage divider, the other input of which is connected to the first output of the control unit, the other outputs of which are connected respectively to the input. . to reset the first and additional integrators, the inputs of which are interconnected, and the output of the first integrator is connected to the corresponding input of the control unit, the control input of which is connected to the control input of the maximum selection unit, the control input of the pseudo-random code generator and the first output of the search and synchronization unit whose second output is connected to,. corresponding inputs of the comparison unit and voltage multipliers of both symmetrical and frequency-spaced processing channels, and the output of the first band-pass filter is connected to the input of the first quad. 40 fifty.