SU807500A2 - Method of switching-off frequencies in systems with frequency manipulation - Google Patents

Description

(54) METHOD FOR SWITCHING FREQUENCIES

IN SYSTEMS WITH FREQUENCY MANIPULATION

FIG. 1 and FIG. 2 is a circuit diagram of a device enabling the implementation of this method for switching frequencies in systems with frequency shift keying ;.

This method is carried out as follows.

The master oscillators 1 and 2 produce initial oscillation with frequencies and f, which are supplied through blocks 3 and 4 of the phase change to electronic keys 5 and 6. The input binary modulating signal goes to bus 7, synchronizer 8 and differentiating element 9. At the time of changing the field of the modulating signal, corresponding to the transition 0-1, the control pulse through bus 10 of differentiating element 9 enters the phase changing unit 3 in the master oscillator circuit 1, and during transition 1-0, the control pulse from the output bus 11 differs iruyuschego element 9 enters into another block 4 phase variation. Blocks 3 and 4 of the phase change are also fed across the bus 12 by the difference frequency signal fA from the mixer output of 13 frequencies, which, KpDMe addition, goes to the control inputs of the synchronizer 8 and switches the electronic keys 5 and 6 at the time when the signal phase the difference frequency fu is zero.

At the moment of arrival of the controlled pulse in blocks 3 or 4 of the phase change, the phase of the corresponding shaping wave with frequency f or f, j is changed by an amount equal to the phase of the signal of the difference frequency. At the same time, at the moment of changing the polarity of the modulating binary signal via bus 7, the phase of the signal of the difference frequency fi on bus 12 is equal to zero, which makes it possible to obtain frequency-manipulated signals with predetermined symbol durations determined by the input binary signal.

To change the phase of the oscillating wave, for example, the signal of frequency f 4 arriving at | 14, it is fed to the first inputs of multiples 15 and 16, and to the second through the phase shifter 17 by 90. To the other inputs of the multipliers, respectively equal to the values of the phase shifted by 90 and the main signals of the difference frequency fu. These constant signals are formed in blocks 18 and 19 of the sample, which are fed control pulses on bus 10 from the output of differentiating element 9 and the signal of the difference frequency f d through bus 12, and to block 18 of the sample, the signal from bus 12 goes through phase shifter 2p at 90 C outputs of multipliers 15 and 16 signals are sent to an adder 21, on the output bus 22 of which I get a oscillation shifted in phase

by an amount equal to the phase of the signal of the difference frequency .f on bus 12 at the time of changing the polarity of the modulating binary signal. In this case, the phase of the signal of the difference frequency

The 5 fA also changes by the same amount and becomes zero. Thus, at the moments of switching, determined by the input modulating signal, the phase difference of the formative oscillations will always be zero regardless of the duration of the symbols of the generated signals, which allows to receive frequency-manipulated signals on the bus 23 without

5 phase breaks with predetermined symbol durations at selected frequencies f and f,

The method for switching frequencies in frequency manipulation systems allows the formation of frequency-manipulated signals without phase discontinuity and with any modulation indices, which allows an increase in the number of possible modulation indices.

Claims (2)

Invention Formula A method for switching frequencies in systems with frequency manipulation according to the author. No. 185967, of those who study. By the fact that, in order to increase the number of possible modulation indices, at the time of changing the polarity of the modulating signal sampling the Rahl signal of the difference frequency of the main and phase-shifted by 90, the values obtained which are multiplied by the phase-shifted by 90 and the main initial oscillation, and the results of the multiplication are summarized. Sources of information taken into account in the examination 1, A.M. et al. Phase Difference Modulation. M., St. Don, 1967, p. 155-157. 2. USSR author's certificate 185967, cl. H 04 L 27/20, 1966 (prototype).