SU553753A1 - Device for separating d-sequences - Google Patents

Description

one

The invention relates to radio engineering and can be used in radio communication and radar systems.

One of known devices for sinhroiizatsnn nsevdoshumovyh signals comprises two multiplier, adder, iitegrator, a PN generator, a key circuit, connected between one of peremiozhiteley and n-2 tap PN generator, wherein the control input is connected to the input device via a threshold device, an integrator and a multiplier input the signal from the signals of the SP -1 removal of the pseudo-noise generator 1.

However, this device requires a significant time to synchronize.

The closest technical solution is a device for separating a D-sequence, containing a sequentially connected filter, a limiter and a delay line whose output is connected to the corresponding input of the correlator and discriminator controlled by a reference generator, to the inputs of which the output is connected respectively. the delay lines are directly, and the output of the voltage controlled oscillator is directly and through the control unit 2.

However, this device also requires considerable time to search for the D-sequence.

The purpose of the invention is to shorten the time spent searching for the D-sequence.

For this purpose, in the device for separating the D-sequence, containing, and its sequence, a filter, a limiter and a delay line, the output of which is connected to

corresponding to them, the input.m of the correlator and the discriminator, controlled by the reference sequence generator, to the inputs of which the output of the delay line is connected directly, and the generator output,

controllable, - directly and through the control unit, additionally modulo-two adder, additional sequence reference generator and frequency divider are entered, and the output of the generator controlled by angulation is connected to the control unit and to the control unit through the divider. additional generator of the reference sequence, the outputs of which are connected respectively to the two additional inputs of the discriminator and to the additional input of the correlator, control, whose input is connected to one 1M from the inputs of the modulo two, to another input of which the output of the delay line is connected, with the output of the modulo adder

Two and an additional output of the control unit are connected to the corresponding inputs of the additional generator of the reference sequence.

The diagram shows a structural electrical circuit of the proposed device.

The device for separating the O-sequence contains a filter 1 connected in series, a limiter 2, a delay line 3, the output of which is connected to the corresponding inputs of the correlator 4 and the discriminator 5, controlled by the reference sequence generator 6, to the inputs of which are connected respectively the output of the delay line 3 directly, and the output of the voltage controlled generator 7 is directly and via the control unit 8; adder 9 modulo two, an additional generator 10 of the reference sequence and a frequency divider 11, while the output of the generator 7 controlled by voltage is connected via a frequency divider 11 to the control unit 8 and to the control input of the additional generator 10 of the reference sequence whose outputs are connected respectively, to two additional inputs of the discriminator 5 and to the additional input of the correlator 4, the control input of which is connected to one of the inputs of the adder 9 modulo two, to the other input of which you are connected One delay line 3, the modulo two output of the adder 9 and the auxiliary output of the control unit 8 are connected to the corresponding inputs of the additional generator 10 of the reference and sequence, and the lowpass filter 12 is switched on to the discriminator 5 and the generator 7, and between the correlator 4 and the control unit 8 - threshold device 13.

The device works as follows.

At the beginning of the synchronization of the voltage on the output of the threshold device 13 is not, therefore, from the output of the control unit 8 receives impulses to enter the evaluation in the shift registers of the generator 6 reference sequence and additional generator 10 of the reference sequence.

After entering k pulses without error into the generator register 6, the latter generates a segment of the D-sequence with period 2, which coincides in phase with the segments of the input D-sequence with period 2. The reference sequence with period 2 enters adder 9 modulo two, another input which input is received D sequence. At the output of adder 9, an O-sequence with periodo- m 2n - /; + 1 j, j width of discrete 2-TC appears. The pulses of this sequence are entered into the register of the additional generator 10. If the estimate of the (n – k - {-) pulses is correct, then the modulo two reference lines from the outputs of the generator 6 and the additional generator 10 give a D-sequence coinciding with the input one. The modal operation of two reference sequences is performed by sequencing the sequences, i.e. when they are fed to the correlator 4 and the discriminator 5. At the output of the correlator 4, if the impulses are correctly evaluated, there will be a voltage exceeding a predetermined threshold level. As long as this exists, the registers of generators 6 and 10 do not receive the next estimates. If at least one of the evaluations is made incorrectly, then as a result, the sum modulo two sequences from the outputs of the generators 6 and

10 does not give the input sequence. In this case, the voltage at the output of the correlator 4 decreases sharply, and there is no voltage at the output of the threshold device 13. From the output of the control unit 8 prohibiting

the impulse does not come in and the registers of the generator 6 and the additional generator 10 receive new estimates.

In synchronization mode, the input sequence slides relative to the received one. Sliding is stopped after combining the input and reference sequences. Sliding is provided by the control unit 8 due to the fact that the input elements of the input sequence are entered into the registers of the generators 6 and 10 not through a period of the sequence, but through a time equal to (), where m is the output sequence discrete.

The need for sliding is due to the fact that generator 6 generates a sequence with period 2, and the input sequence contains both segments of the generated sequence and different in structure from the generated one. Under favorable conditions, the input of the generator is 6 nocTynaiOT characters with which it is matched. In this case, the generator 6 is included in the synchronism of the segment, ensuring successful

synchronization for the additional generator 10. Under favorable conditions, generator 6 is not included in synchronization m, which leads to the introduction of new estimates in generators 6 and 10. A change in ratings is observed until

while in the registers of generators 6 and 10 will not

do elements of negotiation with

which agreed these generators 6 p 10.

If the period of the input D-sequence

2 32, and generators 6 and 10 generate sequences with a period, the synchronization time is doubled. This result is better than the step correlation method. The gain in the absence of noise is 8, if 2 32,

Claims (2)

1. Authors certificate of the USSR D 299979, cl. H 04 L 7/02, 1971 - equivalent. 2. Ward. Differentiation of pseudo-noise signals by the method of evaluation. “Foreign Radio Electronics N ° 8, 1966- prototype. / J NZ-- Sh , „. i //