SU1499522A2 - Receiver of signals of triple phase manipulation - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to provide reception of signals of four-position shift manipulation. The receiver contains phase detectors 1-6, logic block 7, decoder 8, reference gr. 9, phase shifters 10, filter 11, adder 12, multipliers 13 and 14, waiting for multivibrators 15-22 and 28-30, inverter 23, electric You are 24-27, the information signal detector 31 and the EL-32 signal. The goal is achieved by automatically unambiguously determining the positionality of the received phase-shifting signal. 1 dw., 3 tab.

Description

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The invention relates to telecommunications technology, can be used in radio communication systems, radio telemetry and data transmission and is an improvement of the invention according to the author. No. 1283995.

The purpose of the invention is the reception of signals of four-position manipulation with a shift.

The drawing shows a structural electrical circuit of the proposed receiver.

The receiver contains six phase detectors 1-6, logic block 7, decoder 8, reference generator 9, phase shifters 10, filter 11, adder 12, multipliers 13 and 14, the first - the eighth pending multivibrators 15-22, inverter 23, quarter 24, third 23, the first 26 and the second 27 elements And, the ninth 28, the tenth 29 and the eleventh 30 waiting for multivibrators, the detector 31 of the information signal and the element OR 32.

The receiver works as follows.

The receiver receives a phase-shift (FMN) signal of the form

 one

A, (t) (cOt + -I IT + Cfc),

where AL, 0} is the amplitude and carrier frequency of the signal; C) c - random starting phase

received signal; i - random information parameter of the signal, depending on the type

The signal can take the table. 1. value

Initially, we consider the operation of the device without taking into account the peculiarities of the signals of 4-FMN with a shift that is in the absence of phase jumps of 180 °.

The second inputs of the phase detectors 1-6 from the output of the reference generator 9 receive oscillations through the phase shifter 10 of the form

U, (, cos (wt + - | - + Cfr);

i (t) (iut + -g-li + Cfr); U, (t) (ut - -g-IT + tf); U4 (t) A (, cos (txit - - | - + (f) - (1)

U (t) (wt - - | -);

U (t) (a) t),

where tf is the initial phase of the reference oscillations. Phase Detector Outputs 1-6

stresses are formed

 Aok / i-1 7 .... h

g. . , AoK xl-I,., H

Zg - | - COS (+ AH),

where (4 with -tfrJ

k is the transmission coefficient of the phase detector.

Eight different combinations of signals are formed at the outputs of phase detectors 1-4. Depending on the value of the signal information parameter. By acting on the inputs of logic block 7, these combinations are converted into a signal at one of its outputs, which is informational.

From the output of logic block 7, the information signal is fed to the decoder 8. The latter is a digital-to-analog converter, which generates signals at its outputs

S, cos (-T- i); 3; sin (-r- ti).

From the outputs of the phase detector 5 and the decoder 8, the signals Zj and S are received at the inputs of the multiplier 13. At the output of the multiplier 13, a signal is generated

U, j - | b cos (i + | -Hulf) cos (Tr).

Similarly, at the output of the multiplier 14, a signal is generated

 K. / 1 I. “/ I I cos (- 7 + u4) sin (--- n).

After the summation of the signals Ujj and the output of the adder 12, a signal is formed

U ,,, схпйЦ).

(3)

The voltage entering through the filter 11 to the reference generator 9 adjusts the phase of the reference oscillations by the value of C), ensuring the coherence of the oscillations of the reference generator 9.

From expression (3) it can be seen that the control voltage on the code of adder 12 is proportional to the phase shift between the signal and generator frequencies and does not depend on the information parameter i. Therefore, the coherent oscillation formation chain turns out to be invariant to the positioning of the QPSK signals. In addition, the structure of the decoder 8 also does not depend on the parameter i, since it is designed for all its possible combinations.

Thus, the proposed receiver is invariant with respect to signals of the type 2-, 4-, 8-FMN.

Consider the algorithms for automatically determining the positioning of the FMK signal.

In the synchronism mode & Lf О, therefore, using the expression (2), taking into account the logic of the operation of block 7, you can make a table. 2

From a comparison of the data table. 1 and 2, when the 8-Fmn signal arrives at the receiver's input, appearance 1 is possible on all outputs of block 7; in the case of a 4-FMN signal, 1 is formed on the corresponding four outputs of block 7; corresponding two outputs of block 7.

The signals from the outputs of logic block 7 through the corresponding pending multivibrators 15-22 arrive at the inputs of the detector 31. When received at the input of the corresponding multivibrator 1 5 1, the voltage at its output remains unchanged for a time t (50 ... 100) T where T is the duration of the elementary signal. This makes it possible to simultaneously observe at which outputs of the logical block 7 there appeared 1.

The algorithm of operation of the detector 31 is presented in table. 3

Such an algorithm of the detector 31 makes it possible to unambiguously determine the positionality of the received QPSK signal.

Consider the features of the receiver associated with the algorithm for detecting the sign of a 4-PSK signal with a shift.

In the case of receiving 4-FMN signals with a shift, the described order of operation of the device remains unchanged, since the shift signal, like a simple 4-FMN signal, has four phase positions. The only difference is that in the signal with a shift there can be no phase jumps by 180, and in the signal without a shift they necessarily take place. This means that at the outputs of logic block 7 in the first case, transitions 1 from one output to another cannot occur in the order that is defined by the expression.

R

1-1

at 4

with n 4,

where, 8 is the number of the output on which 1 was observed at the given time,

p ± 4 is the number of the output at which 1 is observed at the moment of time following the phase jump. In the second case, such transitions are necessarily observed.

Suppose that a 4-FMN signal is received at the receiver input, and the parameter i currently has a value corresponding to the logic level 1 at the first output of block 7. In addition, the second output of the detector 31 is set to 1, meaning that the received signal is four - positional. The logical level 1 from the output of the block 7 is fed to the input of the standby multivibrator 28, which runs on the falling edge of the input

pulse. Since 1 is present at the first output of block 7, then O is observed at the fifth output. O. Let the signal phase jump by 180 ° occur. In this case, the logic level 1 appears at the fifth output of block 7, and the first output is set to O. At the time of the phase jump, a stand-by multivibrator 28 is started, the output of which produces a pulse with a logic level 1 of duration t (0.25. ..0.5) T. This 1 is fed to the first input of the element AND 19, to the second input of which 1 is supplied from the fifth output of the block 7. As a result

7 1

; at the output of the element I.26, a stand-by multivibrator 30 starts up through the element OR 32, at the output of which a level of logical 1 is formed, which remains unchanged during the time t (50 ... SO). This level goes to the first input of the element And 25 and through the inverter 23 to the first input of the element And 24. At the second inputs of the elements 24 and 25 there are 1, coming from the second output of the detector 31. At the output of the element 25 it is observed 1, and at the output element and 24. This means that the received 4-FMN signal is a signal without a shift, since it has phase jumps of 180. For the initial state in question, the inputs of the waiting multivibrator 29 and element And 27 are always O, and these elements do not participate in the work.

If at the moment of the phase jump of the signal; -la no transition 1 is observed from the first to the fifth outputs of block 7, then And 26 1 does not appear at the second input of the element. Therefore, the voltage levels at the outputs of the AND 26 and OR 32 elements and the waiting multivibrator 30 correspond to a logical O. Then O comes to the second input of the AND 25 element, and 0 to the second input of the AND 24 element from the output of the inverter 23. 24 is set to 1, and at the output of AND 25 is O. This means,; that the input signal does not have jumps

phases by 180.

The days of the initial state C 1 at the second output of block 7, the phase jump detection algorithm for 180 is similar to that described, only a running multivibrator 29 and the AND element 27 participate in the work, and the inputs of the waiting multivibrator 28 and the And 26 element are always observed.

Therefore, if 1 is set at the output of AND 25, then a signal is received without a shift, and if 1 is set

eight

at the output of the AND 24 element, the received 4-FMN signal is a signal with a shift.

Claims (1)

Invention Formula 0 five 0 five five 0 The receiver of signals of a threefold phase shift keying according to auth.St. No. 1283995, characterized in that, in order to receive four-position shift manipulation signals, ninth, tenth, eleventh waiting multivibrators, four AND elements, an OR element and an inverter are introduced, and the first output of the logic unit through the ninth waiting multivibrator connected to the first input of the first element I, the second input of which is connected to the fifth output of the logic unit, the second output of which is connected to the first input of the second element I through the tenth waiting multivibrator, the second input of which is connected to the sixth output logic block, the outputs of the first and second elements And connected to the inputs of the OR element, the output of which through the eleventh waiting multivibrator is connected to the input of the inverter and the first input of the third element And, the output of the inverter is connected to the first input of the fourth element And, the second input of which and the second input of the third Element I is connected to one of the inputs of the information signal detector, the outputs of the third and fourth elements I are the corresponding 11 AND outputs of the receiver. Table 1 View 8-ppm signal 4-Fmn 2-Fmn table 2