SU543194A2 - Communication system with first-order phase difference modulation - Google Patents

Description

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The invention relates to communication technology and can be used when receiving discrete information signals at an unstable carrier frequency.

According to the main author. St. JVo 451166 known communication system with phase difference modulation (FRM) of the first order, containing the transmitting part with the first order FRM and communication channel, the output of which includes the second order FRM receiver containing two quadrature autocorrelators consisting of a common a memory element for a HALF parcel duration, a phase shifter, two non-multipliers and two integrators with a reset, the outputs of which are directly and through other memory elements half a time the parcel is connected to the corresponding multipliers, the outputs The latter through the court are connected to the threshold element, the other input of which is connected to the synchronization device, which is also connected to the memory elements and half the sending time and to the reset inputs of the integrators 1.

However, the known communication system does not have sufficiently high noise immunity to additive noise due to the deterioration of the energy ratios due to the need to process only half of the information packets.

In order to increase the noise immunity to additive noise, an additional su.mmator and memory element are inserted into the proposed communication system for half the duration of the sending, with one output of the synchronization and control unit connected to the first input of the additional adder and the other to the second input of the additional the adder through an additional memory element for half the duration of the package, the other input of which is connected to the output of the adder and to the third input of the additional adder, the output of the latter is connected input of the threshold element.

The drawing shows a structural electrical circuit of a communication system with first-order phase-difference modulation.

The first order FRM communication system contains the transmitting part of the first PRM

order and communication channel (not shown in the drawing), the output of which includes a second order FRM receiver containing two quadrature autocorrelators consisting of a common memory element 1 for half the duration of the parcel, a phase shifter 2, two multipliers 3, 4 and two integrators 5, 6 with a reset, the outputs of which are directly and through other elements of memory 7, 8 for half the duration of the package are connected to

the corresponding multipliers 9, 10, the outputs of the latter are connected to the inputs of the adder 11, and its output is connected to one of the inputs of the additional memory element 12 for half the sending time and through the additional adder 13 to the input of the normal element 14. The inputs of the additional adder 13 through the additional element the memory 12 and is directly connected to the corresponding outputs of the synchronization and control device 15, also connected to the memory elements 7, 8 and to the reset inputs of the integrators 5, 6.

The proposed communication system operates as follows.

From the output of the communication channel, the signal in the form of high-frequency filled pulses and different initial phases goes to one of the inputs of multipliers 3 and 4 directly, and to the other inputs through a common memory element 1 (for multiplier 3) and through the same memory element and phase shifter 2 (for multiplier 4). The signals received at the outputs of the multipliers 3 and

4, are integrated within O, where t is

the duration of the parcel, in the respective integrators 5 and 6, operating in the reset mode.

Thus, the integration is performed sequentially for each of the half of the incoming parcels (except for the first parcel in the transmission, when the work has not yet been established).

At the end of the integration integrators

5.6, the signal from the synchronization device 15 is reset (cleared).

The part of the system consisting of memory element 1, phase shifter 2, multipliers 3, 4, and integrators 5, 6 forms two quadrature autocorrelators that use a common memory element 1 and differ only in the phase shift by -ir / 2 between the multiplied vibrations . These autocorrelators tori form a voltage proportional to the cosine and sine of the difference of the current phase of the two halves of each package at one stage (“even stages) and the second half of the second and first half +1 package at other stages (“ odd stages). During the operation of the circuit, these stages alternate, and for a time of 2, there are two "even and one" odd stages.

Next, the DC samples are received by pa multipliers 9, 10 directly and through the memory elements 7.8, which are used at the inputs of the multipliers 9 and 10 to process the results of the "even and" odd stages. Nano lchbni with exits

multipliers 9 and 10 are fed to the inputs of adder 11, at the output of which, at a time equal to the duration of the parcel, voltages appear at intervals of m / 2 proportional to the sum of the results of processing, respectively, at the first "even and subsequent" odd stages and the same "odd and the next “even stages.

The voltages obtained in this way are fed to one of the inputs of the additional

the adder 13 directly, and on the other through the additional memory element 12. Upon completion of the summation of the signals from the synchronization and control device 15, the additional cumulator 13 and the additional memory element 12 are reset. The voltage removed from the output of the additional adder 13 is compared with the specified threshold threshold element 14, where the voltage sign corresponding to the transmitted binary symbol is determined.

Claims (1)

1. Copyright certificate № 451166, D. Cl.2 P 03D 3/02, 1972 (prototype).