SU476697A1 - Correlation discriminator for time delay pseudo-random sequence synchronization - Google Patents

Description

telegraphic

This invention relates to communications.

A correlation discriminator for synchronizing the time-delay of a pseudo-random sequence and using two orthogonal codes, containing a non-multiplier, the first input of which receives the received signal, a low-pass filter, the output of which through a controlled generator is simultaneously connected to the inputs of the first and second pseudo-random generators.

The purpose of the invention is to improve the synchronization accuracy without changing the structure of the transmitted signal.

This is achieved by the fact that the outputs of the advancing and lagging reference signals of the first pseudo-random sequence generator are connected respectively to the first and second inputs of the first subtractive node, the output of which is connected to the second input of the multiplier through the first input and output of the second multiplier, and the outputs of the second and second lagging reference signals pseudo-random sequence generator is connected respectively to the first and second inputs of the second subtractive node, the output of which is of the connections to the second input logic

forming unit, and the output of the multiplier is connected to the input of the low-pass filter.

FIG. 1 shows a functional diagram of the proposed device; in fig. 2 - shaper reference signal; in fig. 3 - discriminatory characterization.

The device contains a multiplier of the received and reference signals 1, the low-pass filter 2, the controlled oscillator 3, the shaper of the reference signal 4, the pseudo-random sequence generators (PSP) 5 and b.

The shaper of the reference signal 4 contains a logical shaping unit 7, the output of which is connected to the clock of the reference signal and the inputs are connected to the logical subtractive nodes 8 and 9, each

of which is connected to the outputs of two stages of different generators PSP. Xi and Xz are two reference sequences removed from a series of cascades of one of the generators of the SRP; Y and Y are onopm, ie, sequences removed from a series of cascades of another generator. A and B are the input signal and the multiplier output, respectively. To form a discriminatory characteristic (Fig. 3)

in the discriminator, the following operations are performed: e --- qx X (t-tn) - bz, X (t + tn) + + and, y (t--, + and, - y (i + -.,}, (1) where X: (t - Тц) л: 1 - leading reference signal; (+) А2 - lagging reference signal; y (t - т „) 1/1 - leading reference signal; g / (/ + Tn) g / 2 - lagging reference reference plate. I will transform expression (1) to the type Ud - C / zx1 l (-t „) - l: (+ n) + + {/ (-„) - у (+ „)) Forming the support signal according to the expression in braces (2), determines the possibility of reducing the number of multipliers. When forming the reference signal, the subtraction and addition are transferred to the low frequency range. 5 10 15 20 25 30 Pre METHOD OF THE INVENTION Correlation discriminator for time delay synchronization of a nsvn-random sequence using two orthogonal codes, containing a multiplier, the first input of which is the node and the received signal characterized in that, in order to improve synchronization accuracy without changing the structure of the transmitted signal, the outputs of the opera The reference and lagging reference signals of the first pseudo-random sequence generator are connected respectively to the first and second inputs of the first subtractive node, whose output through the first input and output of the logical forming unit is connected to the second multiplier input, and the outputs of the leading and lagging reference signals of the second pseudo-random sequence generator are respectively connected to The first and second inputs of the second subtractive node, the output of which is connected to the second input of the logical ф an accommodating unit, with the output of the multiplier connected to the input of the low-pass filter.

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