RU2131644C1 - Multiple-channel device for reception of voice signals - Google Patents

Abstract

FIELD: telephone equipment. SUBSTANCE: device has generator of orthogonal signals, linear unit, paraphase unit, correlation units. Goal of invention is achieved by introduced signal selection unit, control signal generator, second paraphase unit, generation unit, error suppression unit, output unit, and generator of pseudorandom sequence. Number of generation units corresponds to number of channels. Number of error suppression unit corresponds to half of number of channels. EFFECT: use of encrypted confidential information from modulated orthogonal signals, which represent in communication channel sum of phase constituents of modulated signal. 1 dwg

Description

 The invention relates to a multi-channel communication technique and can be used to extract masked confidential information from modulated orthogonal signals representing in the communication channel the sum of the phase components of the modulated signal.

 Known multi-channel receiving devices with separation of channels in the form of signals, containing a function generator, a clock generator, a linear unit whose output is connected to the inputs of the first multipliers, the outputs of which are connected to the inputs of the second multipliers, the outputs of which are connected to the inputs of the low-pass filters, have low reception accuracy due to the complexity of modeling orthogonal signals, the use of analog and nonlinear circuits [1].

 The closest in technical essence is a multi-channel receiving device containing an orthogonal signal generator, the first input of which is connected to the input of the measuring clock driver, the first output of which is connected to the input of the reset unit, a linear block whose output is connected to the first input of the paraphase block, correlation blocks, each of which consists of two matching circuits connected through the assembly circuit to the first input of the integrator, the first inputs of the matching circuits of each correlation block are connected to the corresponding output outputs of the paraphase block [2].

 The disadvantage of this device is the possibility of unauthorized access to transmitted masked confidential information.

 The objective of the invention is to remedy this drawback. The problem is solved as follows.

 The known device is equipped with a signal selection unit, a driver of the control signals, a second paraphase unit, generation units, error correction units, an output unit and a pseudo-random sequence generator, the number of generation units corresponds to the number of channels, and the number of error recovery units to half the number of channels, each generation unit consists of from the cutter pulse shaper connected through an amplifier to the first input of the quantized level reconstruction element, the first input d the cut-off pulse shaper is connected to the second output of the clock shaper, the second input of the cut-off pulse shaper is connected to the integrator output, the second input of the quantized level recovery element is connected to the second output of the reset unit, the output of the quantized level recovery element is the output of the generation block, and the error elimination block consists from the comparison element and the subtracting element, the second output of the orthogonal signal generator is connected to the input of the pseudo-random generator The output signal is connected through the driver to the first input of the signal selection block, the remaining inputs of this block are connected to the corresponding outputs of the orthogonal signal generator, the outputs of the signal selection block are connected to the corresponding inputs of the second paraphase block, the second inputs of the matching circuits are connected to the corresponding outputs of the second paraphase blocks, the outputs of the odd blocks of formation are connected to the first input of the comparison element and the first input of the subtraction element, the outputs of the even blocks s formation connected to the second inputs of the comparing elements, outputs of which are connected to the second input of the subtractor, the subtractor outputs are connected to respective inputs of the output unit.

 The drawing shows a diagram of the device.

 The device comprises an orthogonal signal generator 1, a measuring pulse shaper 2, a reset block 3, a linear block 4, a pseudo-random sequence generator 5, a signal selection block 6, a matching circuit 7, an assembly circuit 8, an integrator 9, a cut pulse shaper 10, an amplifier 11, an element 12 restoration of the quantized level, the driver of the control signals 13, the subtracting element 14, the comparison element 15, the first 16 and second 17 paraphase blocks, the correlation element 18, the forming unit 19, the error correction unit 20, the output block 21.

 The device operates as follows.

 A complex composite signal of modulated orthogonal oscillations, representing the sum of the phase components of the modulated signal, is fed from the communication line to the input of the linear block 4. From the output of the linear block, the composite orthogonal signal is fed to the input of the first paraphase block 16, at the output of which direct and inverse signals of the incoming composite appear simultaneously modulated orthogonal signal. These signals are fed to the inputs of the correlation elements 18, consisting of two coincidence circuits 7 (direct and inverse), the outputs of which are connected to the inputs of the assembly circuit 8, the output of which is connected to the input of the integrator 9. Also, direct and inverse orthogonal signals are received at the inputs of the correlation elements 18 reference oscillations from the second paraphase block 17. To the paraphase block 17, the orthogonal signals of the reference oscillations are started from the orthogonal signal generator 1 through the signal selection block 6. Block 6 signal selection performs the selection of orthogonal signals from the entire set of signals of the reference oscillations generated by the generator 1, synchronously with the same device in the transmitting unit. Synchronism is achieved by phasing the generators of orthogonal oscillations of the transceiver devices through a dedicated channel for intercom. The selected set of distribution of orthogonal signals between the correlation elements 18 is stored for a certain point in time, called the switching period of the modulation signal selection block 6. The switching period of block 6 is set by the pseudo-random sequence generator 5. The generator 5 is synchronized with the generator 1 of orthogonal signals, its operation is the pseudo-random selection of a sequence of digits. The selected pseudo-random sequence is started from the output of the generator 5 to the input of the driver 13 of the control signals. According to the sequence received, the driver 13 generates control signals that are input to the input of the modulation signal selection block 6. According to the received control signals, block 6 switches the orthogonal signals between the correlation elements 18.

где Q - восстановленный сигнал,
Y_i(t) - составляющие сложного модулированного ортогонального сигнала;
Y_опi(t) - ортогональные сигналы опорных колебаний.The work of the correlation element 18 is based on the implementation of formula (1):

where Q is the reconstructed signal,
Y _i (t) are the components of a complex modulated orthogonal signal;
Y _opi (t) - orthogonal signals of the reference oscillations.

In order to completely isolate the signal for the entire integration period, inverse components Y _i (t) and Y _opi (t) are also processed by formula (1). Those. as applied to the circuit of the correlation element 18, the direct components Y _i (t) and Y _opi (t) were multiplied in the first coincidence schemes 7, the inverse components Y _i (t) and Y _opi (t) were multiplied in the second coincidence schemes 7. The selected signal for the first half-cycle in the first coincidence circuit 7 and the signal allocated for the second half-cycle in the second coincidence circuit 7, are supplied to the assembly circuit 8, at the output of which a signal is generated for the full period. The received signal is fed to the integrator 9, the second input of which starts the zeroing pulse from the block 3 reset. With this pulse, the integrator 9 is zeroed at the beginning of each integration period. At the output of the integrator 9, sawtooth pulses are formed, the final amplitude of the pulse depends on the amplitude of the demodulating signal and carries speech information. The signal demodulated in the correlation element 18 is supplied to the forming unit 19.

 The forming unit 19 consists of a pulse cutter 10, the output of which is connected to the input of the amplifier 11, the output of which is connected to the input of the recovery element 12 of the quantized level. At the input of the pulse shaper of the notch 10 from the integrator 9 of the correlation element 18, a speech signal in the form of an increasing sawtooth pulse is preliminarily selected from the orthogonal modulated oscillation. At the second input of the shaper 10, a sequence of rectangular pulses is synchronized with the period of the sawtooth pulses, which provides the selection of the cutting pulse from the rising sawtooth pulse in a given time interval, from the shaper of the measurement step 2. At the output of block 10, signal samples are generated with a given repetition period and with an amplitude equal to the terminal amplitude of the ramp pulse. The generated samples of the signal are fed to the input of the amplifier 11, from the output of which the amplified samples go to the input of the recovery element 12 of the quantized level. At the second input of element 12, a zeroing pulse is started from the reset unit 3. The zeroing pulse sets the element 12 to the zero position before applying the countdown of the information signal coming from the amplifier 11. The counting of the signal transfers the element 12 from the zero state to the storage state of the information level. At the same time, a signal with a constant voltage level equal to the level of the information readout received at its input will be output at the output of element 12. A voltage with a constant level is issued from element 12 until the arrival of the next information readout. With the arrival of the next reference element 12 resets the previously stored level with a zeroing pulse and remembers the level of the new reference. As a result, a quasi-continuous signal is formed at the output of element 12, the shape of which corresponds to the speech signal of the first analog channel.

 According to the same scheme and a similar algorithm, the speech signals of the remaining analog channels are restored. In this case, the restored speech signals in the adjacent channels carry the same information, since on the transmitting side the orthogonal carrier signals of the adjacent channels are modulated by the same speech signal inverse to each other. The restoration of one speech signal in two channels is carried out in order to detect errors introduced by the communication channel in the original speech signal. For this, an error correction unit 20 is introduced into the device.

 The error correction unit 20 consists of a comparison element 15 and a subtracting element 14. The restored speech signals from adjacent channels carrying information of one initial speech signal are supplied to the inputs of the comparison element. At the output of the device, an error is introduced that is introduced into the original speech signal due to its transmission over the communication channel. The calculated error is fed to the input of the subtracting element 14, to the second input of which one of the recovered speech signals is fed into the error elimination unit 20. The subtracting element 14 compensates for the error introduced by the communication channel in the recovered speech signal. The signal received in the block for eliminating error 20 is supplied to the output block 21.

 Block 21 receives signals of confidential multichannel speech information extracted from the total signal of modulated orthogonal oscillations. Isolation of multichannel speech information from such a sum signal, representing in the communication channel the sum of the phase components of modulated orthogonal oscillations, by other receiving devices or existing search devices, is impossible.

Sources of information
1. H. F. Harmouth "Information transfer by orthogonal functions", M .: "Communication", 1975, p. 95.

 2. USSR author's certificate N 367561, cl. H 04 J 9/00 published March 13, 73

Claims (1)

 A multichannel device for receiving speech signals containing an orthogonal signal generator, the first output of which is connected to the input of the measuring clock driver, the first output of which is connected to the input of the reset unit, and correlation elements, each of which consists of two matching circuits connected through the assembly circuit to the first the input of the integrator, the second input of the integrator is connected to the first output of the reset unit, and the linear block, the output of which is connected to the input of the first paraphase block, the outputs of which are connected to the first input corresponding matching circuits, characterized in that it is equipped with a signal selection unit, a control signal generator, a second paraphase unit, generation units, error correction units, an output unit and a pseudo-random sequence generator, the number of generation units corresponds to the number of channels, and the number of error removal units to half the number of channels, each forming unit consists of a notch pulse shaper connected through an amplifier to the first input of the restoration element of the quantized level, the first input of the notch pulse generator is connected to the second output of the measuring pulse generator, the second input of the notch pulse generator is connected to the integrator output, the second input of the quantized level recovery element is connected to the second output of the reset unit, the output of the quantized level recovery element is the output of the forming unit, and the error elimination unit consists of a comparison element and a subtracting element, the second output of the orthogonal signal generator is connected to the input g a pseudo-random sequence generator, the output of which is connected to the first input of the signal selection block through the control signal generator, the remaining inputs of this block are connected to the corresponding outputs of the orthogonal signal generator, the outputs of the signal selection block are connected to the corresponding inputs of the second paraphase block, the second inputs of the matching circuits are connected to the corresponding outputs the second paraphase block, the outputs of the odd formation blocks are connected to the first input of the comparison element and the first input of e ment of subtraction, the outputs of the even blocks forming connected to second inputs of the comparing elements, the outputs of which are connected to the second input of the subtractor, the subtractor outputs are connected to respective inputs of the output unit.