SU452068A1 - Pulse selector by frequency - Google Patents

Description

(54) SELECTOR PULSES FOR FREQUENCY FOLLOWING

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The invention relates to radio engineering and can be used for pulsing with different tracking frequencies.

Pulse selectors are known to contain a pending multivibrator and a matching circuit.

A disadvantage of the known selectors is that it is possible to indiscriminately select pulses in the high and low frequencies simultaneously.

In order to select the impulses without distortion in the high and low frequencies simultaneously, the input pulse sequence is fed to the first inputs of key circuits, the second inputs of which are connected to the outputs of the waiting multivibrator, whose input is connected to the input terminal of the selector through a delay element.

FIG. 1 shows the scheme of the proposed pulse selector; in FIG. 2, time diagrams of operation at various points of the selector; in fig. 3 - attenuation characteristic of the selector. The pulse selector consists of a delay element 1 whose input is

the selector input, and the output is connected to the input of the standby multivibrator 2 with zero recovery time.

The direct in and inverse r outputs of the standby multivibrator 2 are connected to key circuits 3 and 4. The second inputs of key circuits 3 and 4 are connected to the input of the selector. The outputs of the key circuits 3 and 4 are the outputs of the pulse selector.

The delay element 1 should provide a delay in the input pulses at the time

xC This is a normalzad. T nmp.

Noah the work of key schemes.

The selector works as follows. With a sufficiently low start frequency.

i.e. when / yy waiting mulmult.-C) imp.

Tivibrator 2 generates at its outputs signals, the duty cycle of which is greater than one. The inverse output of a multlush vibrahzra 2 waiting for this case is resolving for key circuit 4, and at

/ | (the selector (Fig. 2) impulses are formed, the duration and time of KOTopi.ix correspond exactly to the input pulses. Direct output to the pending multivibrator 2 is prohibiting for key circuit 3, and at the selector point e (fig. 2) there will be a low potential, if the launch frequency is such that i-f is at the direct output to the cartoon. / imp. of the waiting multivibrator 2 sets a high potential, i.e. the duty cycle is equal to one, and at the inverse output g the potential is low. The high potential is decisive for the key circuit 3, and at the e output (Fig. 2, and, C) pulses are formed, the duration and temporary position of which exactly correspond to the input pulses. The low potential is prohibiting for the key circuit 4 and at its output (Fig. 2, Ce) there will be a low potential. The proposed pulse selector responds to an instantaneous change in the pulse follow-up period, i.e., to the temporal position of two neighboring selectable pulses. In this case, a complete suppression of signals in the delay region and a complete transmission in the transparency region are ensured, and an infinitely large slope of the attenuation characteristic at the boundary between these regions is provided. Providing the necessary threshold frequency of selection is accomplished by choosing what can easily be done. to carry out in a wide range, the formation of the same undistorted output pulses with a large slope of the characteristic at the limiting frequency is carried out with the help of a key circuit, which can be used with any key circuit that transmits whole pulses. Thus, the proposed device performs the functions of a pulse selector of both high and low frequencies at the same cut-off frequency. Since the duration of the output pulses exactly repeats the duration of the input pulses, these pulses can be used, if necessary, for the selection of the duration. If it is necessary to select pulses only higher or lower than a given frequency, then one of the key schemes can be excluded. . The subject of the invention is the Pulse Selector with respect to the following frequency, which contains a waiting multivibrator and a key circuit that is exposed; so that, in order to select the pulses in the high and low frequencies simultaneously, the input pulse sequence is fed to the first inputs of the key circuits, the second inputs of which are connected to the outputs of the waiting multivibrator, the input of which is connected to the input terminal of the selector through a delay element.

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