SU817985A1 - One-shot multivibrator - Google Patents

Description

(54) SINGLE VIBRATOR

The invention relates to a pulse technique and can be used, for example, as a generator of selector gates in pulse selectors in terms of duration. Single vibrators are known, containing a standby multivibrator with a starting transistor and a driving capacitor from the capacitor charge circuit, the duration of the generated pulses is adjusted depending on the control voltage on the base of the emitter follower 1. However, these single vibrators do not provide automatic control of the duration of output pulses depending on from the time parameters of the input pulses. Closest to the present invention is a single vibrator containing a standby multivibrator and a controlled current switch in the circuit, the time of the master element of the standby multivibrator 2. The disadvantage of such devices is that the duration of the output pulses is not controlled depending on the pulse period of the input pulses, which creates the possibility of skipping input signals, for example, when using such a generator as a generator of selector gates in pulse selectors for the duration, when following the input impulse Som subsequent input pulses are applied to the selector input before it zakonchits forming the selector gate for the previous input pulse. This disadvantage arises due to the fact that the one-shot cannot be re-triggered by the next input pulse if it is already in the active mode of forming the output pulse. The purpose of the invention is to control the duration of the output impulses depending on the follow-up period of the input pulses. This goal is achieved by introducing an additional waiting multivibrator and a matching element connected to its output and inputs, respectively, to the control input of the current key and to the output and to the known one-shot vibrator containing the standby multivibrator and controlled current key in the circuit. the starting input of the waiting multivibrator, the launch input of which is connected to the bus of the input signals through an additional multivibrator.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - time diagrams, according to his work.

The single-oscillator contains serially connected main and additional standby multivibrators 1 and 2, coincidence element 3 connected by its inputs to the input and output of the standby multivibrator, and a current switch 4 installed between the output of the coincidence element and the control input of the waiting multivibrator. As a current switch, a transistor connected as a controllable time of the driving circuit can be used.

The single vibrator works as follows.

Input pulses (diag. A, fig. 2) are fed to the input of an additional standby multivibrator 2 and run for a duration (diagram b), comparable to the recovery time of the standby multivibrator 1, which is started from the falling edge of the pulses from the additional standby multivibrator 2. The standby multivibrator 1 produces pulses, the duration of which, in the absence of a control voltage at the input of the current switch 4, is equal to a constant duration for all trigger pulses, while the duration of the output and pulses are determined by the parameters of the driving time of the Standby multivibrator 1. When a subsequent input pulse appears at the device input, before the end of the output pulse, positive potentials appear at both inputs of the 3d cdB element, i.e. one from the output of the additional standby multivibrator and the other - from the output of the waiting multivibrator. At this, at the output of the coincidence element, a control potential appears that opens the current switch 4, which increases the current in the circuit of the master element of the waiting multivibrator 1, which leads to a reduction in the formation of the output pulse. After the output pulse stops (the first pulse in the diagram in element 3 coincides, the control potential from the current switch 4 (diagram d) is removed and the restoring process characteristic of the waiting multivibrator begins and ends when the trigger occurs of the front of the next pulse, and the waiting multivibrator 1 starts up a second time.

The duration of the output impulse is determined by the period of the following impulses, but does not exceed the maximum duration determined by the parameters of the time of the driving elements of the waiting multivibrator 1 in the absence of the control voltage at the input of the current switch 4.

Thus, the proposed one-shot allows the formation of an output pulse from each input pulse, which, in turn, allows to avoid

input signals if their follow-up period is shorter than the duration determined by the time of the one-shot master elements, while the duration of the output pulses is automatically adjusted depending on the follow-up period of the input, but not longer than the time determined by the parameters of the time of the master elements in the absence of a control voltage on the input current key time master circuit.

Claims (2)

Invention Formula A single vibrator containing a standby multivibrator and a controllable current key in the circuit of the master element of the standby multivibrator, characterized in that, in order to adjust the duration of the output pulses depending on the pulse period of the input pulses, an additional standby multivibrator and a coincidence element are inserted, connected by its output and inputs respectively to the control input of the current switch and to the output and start input of the standby multivibrator, the start input of which is connected to the input signal bar through an extra standby multivibrator. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 414712, cl. H 03 K 3/284, 28.06.71. 2. USSR author's certificate No. 2273.71, cl. H 03 K 3/284, 05.29.67 (prototype). I 1 -H  t (I n  (t yy one