SU1319292A2 - Autocorrelation meter of parameters of pseudorandom phase-shift keyed signal - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to extend the functionality by defining a code structure of a signal. The device contains a multiplication unit 1, a delay element 2, a band-pass filter 3, a non-linear element 4, filters 5, 7, 11,. 20 low frequencies, a tuning rate generator 6, meters 8, 9 frequencies, additional FIG. 1 blocks 10, 19 multiplication, valve 12, pulse counter 13, signal base meter 14, package duration meter 15, arithmetic unit (AB) 16, recording unit 17, 6vioK 18 signal cycling, threshold unit 21, key 22 and additional AB 23. The purpose of the invention is achieved by the introduction of blocks 18-23. Block 18 receives a phase-shift keyed signal (FMS) and measured values of the carrier frequency and the duration of the elementary parcels from the outputs of the meters 9 and 15. Filter 20 separates the low-frequency voltage proportional to the autocorrelation function. Delay value, acc. The maximum of the autocorrelation function, from the delay element 2 through the open key 22 enters AB 23. In AB 23, where the signal from the meter 15 also arrives, a cyclic shift is established, establishing a one-to-one correspondence between the code structure of the received FMS and the conversion function. 1 hp ff, 4 ill. 5 cl oo with o CD Yu ISJ

Description

The invention relates to telecommunications, can be used in systems for transmitting discrete information, in combined communication systems and in radiolocation and is an improvement of the device according to the author. St. No. 921104.

The purpose of the invention is to extend the functionality by defining a code structure of a signal.

FIG. Figure 1 shows the structural electrical circuit of the proposed autocorrelation meter; in fig. 2 is a structural electrical circuit of a cyclic signal conversion unit; in fig. 3 and

4- time diagrams of the autocorrelation meter operation.

The autocorrelation pseudo-random phase-shift keyed signal meter contains a multiplication unit 1, a delay element 2, a band-pass filter

3, nonlinear element 4, the first filter

5b, frequency tuning generator 6, second low-pass filter 7, first 8 and second 9 frequency meters, additional multiplication unit 10, third low-pass filter 11, gate 12, pulse counter 13, signal base meter 14, package length meter 15, arithmetic unit 16, registration unit 17, cyclic signal conversion unit 18, second additional multiplying unit 19, fourth low-pass filter 20, threshold unit 21, key 22 and additional arithmetic unit 23, with cyclic conversion unit 18 The signal consists of the first multiplication unit 24, the first 25 and second 26 delay blocks, the first bandpass filter 27, the second multiplication unit 28, the second bandpass filter 29, the first 30 and second 31 scalable blocks, the first 32 and second 33 tuners.

The autocorrelation meter works as follows.

The received phase-shift keyed (FMN) signal (Fig. 36) with the modulating function (Fig. 3a) is fed to the first inputs of multiplication blocks 1 and 10, Delay element 2 and cyclic signal conversion unit 18. The magnitude of the delay at the first output of the delay element 2 is varied according to a linear law by means of a generator 6, which generates a periodic-saw voltage control. The magnitude of the delay at the second output of the delay element 2 is fixed.

At the second inputs of blocks 1 and 10 of the multiplication, the received FMK signal arrives, which was previously delayed in the delay element 2. The result of multiplication in multiplication unit 1 is high-frequency stuffing beats that pass through the band-pass filter 3 and the non-linear element

4. Filters 5 and 7 of the lower frequencies are tuned.

0

on the high-frequency filling, which is the carrier of the frequency QPSK signal, and the envelope, which is the clock frequency of the pseudo-random modulating function. The outputs of filters 5 and 7 are connected to frequency meters 8 and 9, to the second inputs of which periodically varying output voltage comes from generator 6. As a result, the meter 8 takes information about the value of the clock frequency from the output of the meter 8, and about the value of the carrier frequency of the received FMK signal.

The multiplication in multiplication unit 10 also results in high-frequency fill beats, the envelope of which is extracted by low-pass filter 11 (Fig. Ze).

This envelope is the product of two identical modulating functions (Fig. 3A and e), shifted in time by the amount of delay at the second output of delay element 2.

Number of negative pulses

(Fig. Ze) is equal to the number of phase jumps of the received FMK signal (Fig. 36), moreover

5, the duration of negative pulses does not depend on the duration of the elementary premises. The voltage (Fig. Ze) from the output of the low-pass filter 11 is fed to a single-pole valve 12, the output of which passes only negative pulses.

0 (Fig. Zzh). These pulses are counted by counter 13.

The doubled number of phase jumps during the duration of the received FMK signal is one less than the number of its elementary parcels equal to the signal base.

5 The number of phase jumps counted by the counter 13 is fed to the input of the meter 14 of the signal base, where the signal base is determined.

Information about the value of the clock frequency from the output of the frequency meter 8 arrives at the meter 15, where the clock pulses are formed (Fig. 3c and d), which are used to determine the duration of the elementary parcels. The measured values of the signal base and the duration of the elementary parcels are fed to the arithmetic unit, 16, where the duration of the received QPSK signal is determined.

The values of the signal base, the duration of the elementary parcels, the duration of the signal and the carrier frequency are fed to the corresponding inputs of block 17, where they are recorded. Simultaneously received FMN signal (Fig. 36 and 46) is fed to the first input of the cyclic signal conversion unit 18, the second and third inputs of which receive the measured values of the carrier frequency and the duration of the elementary parcels from the outputs of the meters 9 and 15. The duration of the elementary parcel through the scaling units 30 and 31 enters on

five

control inputs of delay blocks 25 and 26, respectively. The scaling units 30 and 31 provide a multiple increase in the duration of the elementary parcels and, by acting on the control inputs of the delay units 25 and 26, set the corresponding delays (Fig. 4d and 3h).

It should be noted that the phase (Fig. 4c) of the received QPSK signal (Fig. 46) is manipulated in accordance with the modulating function (Fig. 4a), for which the M-sequence is used.

In block 18, the received signal is fed to the first input of multiplication unit 24, to the second input of which the same signal, delayed in delay block 25 (Fig. 4d), is applied, with the phase shown in FIG. 4e. At the output of block 24, a resultant oscillation is formed, from which band-pass filter 27, tuned to twice the carrier frequency, extracts the total voltage (Fig. 4e), the phase of which varies (Fig. 4g).

The voltage from the output of the band-pass filter 27 is fed to the first input of the multiplication unit 28, to the second input of which a signal is applied (Fig. 4h) from the output of the delay block 26 (its phase corresponds to Fig. 4i). At the output of the van 28, a resulting oscillation is formed, from which the band-pass filter 29, tuned to the carrier frequency, extracts the voltage of the difference frequency (Fig. 4k), the phase of which is shown in Fig. 4. 4l.

The tuning of the band-pass filters 27 and 29 is carried out by means of blocks 32 and 33, respectively, the control inputs of which are connected to the output of the meter 9 with a frequency difference.

The voltage from the output of block 18 is fed to the first input of the second additional multiplier block 19, to the second input of which a signal is fed from the first output of the delay element 2.

The low-pass filter 20 extracts a low-frequency voltage proportional to the autocorrelation function, which enters threshold block 21, where it is compared with a threshold level, when exceeded, threshold block 21 generates a control pulse that arrives at the input of key 22 and opens it . In the initial state, the key 22 is always closed. In this case, the value of the delay value corresponding to the maximum of the autocorrelation function through the public key 22 enters the arithmetic unit 23, which also receives the value of the elementary parcels of the meter 15. In the arithmetic unit 23, the cyclic shift is received, which enters the registration unit 17. This shift establishes a one-to-one correspondence between the code structure of the received QPSK signal and the conversion function.

Consequently, by measuring the cyclic shift and having a correspondence table, one can determine the code structure of the received FMN signal.

ten

Claims (2)

1. An autocorrelation meter for the parameters of a pseudo-random phase-manipulated signal according to the author. St. No. 921104, distinguished by the fact that, in order to expand 5 functionality, by determining the signal code structure, the cyclical signal conversion unit connected in series, the second additional multiplication unit, the fourth low-pass filter, the threshold block,  the key and the additional arithmetic unit; the first, second and third inputs of the cyclic signal conversion unit, the second input of the second additional multiplication unit, the second input of the key and the second input and output of the additional arithmetic unit are respectively connected with the second input of the multiplication unit / with the output of the second meter Frequency, with output. Measurement of the duration of the parcels, with the input of the multiplication unit, with an additional output of the delay element, with the second and with the fifth inputs of the registration unit. 2. The meter according to claim 1, characterized in that the cyclic signal conversion unit comprises first and second tuning units, serially connected first multiplication unit, first bandpass filter, second multiplication unit and second bandpass filter, serially connected first scaling unit and first unit delays and successively coupled second scaling unit and a second delay unit, wherein the first input of the first multiplication unit, which is the first input of the cyclic conversion unit, combines en with signal inputs of the first and second delay blocks. 5 outputs of which are connected to the second inputs of the first and second multiplier units, respectively, and the second inputs of the first and second bandpass filters are connected to the outputs of the first and second tuning blocks, respectively, the combined inputs of which are the second input of the cyclic signal conversion unit, the third input and output of which respectively, the combined inputs of the first second scaling units and the output of the second bandpass filter are. , ,,. -gSaadM, +1 WfFig. 2 F Ti lin cm u u u uu fug. 3 bf h H H H H. l H H H,