SU437241A1 - Method of forming quaternary coded sequences of composite signals - Google Patents

Description

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This invention relates to computing and can be used in broadband signal generators.

There is a known method of forming a signal from multi-valued words of the same length expressed in a binary system without the use of delay devices. In this case, according to certain rules, differential phase and amplitude modulation of carrier frequency oscillations is carried out.

However, the known method has a longer time required for synchronization of the received signal.

The aim of the invention is to accelerate the synchronization of received signals.

To do this, zero and one in the even numbers of the binary sequence are replaced by two signals of a certain type, and in odd numbers by two signals of a different kind, orthogonal to the first two signals.

A binary sequence is formed by successively adding the state of an n-bit binary counter, no matter from what bit, high or low, the polling of trigger trigger states begins. In this case, a sequence of length is formed, where n is the number of bits of the binary counter, consisting of 2 natural numbers from O to in increasing or decreasing

order, expressed in bit binary form.

To form a quaternary sequence from the binary, the following operations are performed.

Replace in even numbers O with signal a, 1 with signal p.

Replace in odd numbers with O - signal 7, 1 - with signal b.

The rules for multiplying the symbols a, p, y, b are given in the table.

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Binary length sequence has the following properties:

1) the number of zeros is equal to the number of ones;

2) the sequence is periodic, the period of the sequence is equal to

3) the value of the autocorrelation function is zero for shifts that are not multiples of n;

4) in the general case, the value of the autocorrelation function is not zero at shifts that are multiples of p. The four-sequence sequence length / p2p, formed according to the above rules and conditions, does not have repeating segments longer than -1 characters. For example, in the formation of a quaternary-coded length signal, the states of a three-bit binary counter are used. We write them down, starting with the least significant bit, 000100010110001101011111. From this binary sequence, a quaternary-coded sequence of the form aaa8us 35-saar8 §arrB88 is obtained. FIG. 1 shows the autocorrelation function of the binary length sequence in FIG. 2 is the autocorrelation function of the quad-coded composite signal sequence; in fig. 3 is a structural block diagram of a device with which the proposed method can be implemented. The device contains a clock pulse generator 1, a binary / g-bit counter 2, a decoder of even and odd numbers 3; modulator 4. Clock pulse generator 1 changes the state of the binary n-bit binary counter 2. From the output of the binary counter 2, numbers in the n-bit Binary form in the sequential code are sent to the modulator 4, which also receives commands from the decoder even and odd numbers 3. In the modulator 4, the zeros and ones in the binary sequence are replaced by the signals a, p, 7, b according to the rules indicated above. The subject of the invention is a method of generating four-coded sequences of composite signals from a fixed-length binary sequence, which is obtained by successively attaching multi-bit code combinations consisting of. natural number of numbers, without delay of the generated signals, characterized in that, in order to accelerate the synchronization of the received signals, zeroes and ones in even numbers of the binary sequence are replaced by two signals of a certain kind, orthogonal to the first two signals.

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