SU307507A1 - DURATION SELECTOR - Google Patents

Description

The invention relates to the field of pulse technology and can be used as a device that reacts by generating an output pulse to a deviation of the duration of a rectangular input pulse.

Known pulse selectors for the duration, containing the input integrating / C-chain and the threshold device on the transistor.

In order to eliminate the dependence of the duration of the output pulses on the duration of the input in the proposed device, a blocking oscillator on an automatic bias transistor is used as a threshold device, in which the timing capacitor is connected to the emitter of the transistor and through the source another lining and "plus source included an additional transistor, n. o. due to the bias across the resistor between its base and the source minus and being closed by the input pulses. At the same time, the clock capacitor, during recharging, with the auxiliary transistor closed, functions as a capacitor of the integrating C-chain.

The device consists of a blocking oscillator on the transistor 1 and a key on the additional transistor 2. The timed capacitor 3 of the blocking oscillator is connected by a left plate directly to the emitter of transistor 1.

In the initial state, the key on the transistor 2 is open due to bias through the resistor 4 in the base circuit, while the timing capacitor from the source of the collector voltage is charged to a certain voltage. The constant charge time of the capacitor is chosen to be small, with the result that the device quickly restores its properties after the end of the input pulse. Since the right lining of the clock capacitor is in the initial state connected to the “plus source of the cherkez open transistor 2, then the generation

the blocking generator is not executed. With the arrival of the input voltage pulse i / sx "plus the base of the transistor .2, the latter closes. The timed capacitor is recharged from the voltage source EK through a resistor 5, the secondary winding of the transformer 6 and a parallel automatic bias circuit consisting of a resistor 7 and a capacitor 8, while the voltage C / s on the clock capacitor is applied for a time overcharging time capacitor selection resistor 5 is set significant but compared with a constant charge time and the corresponding minimum duration of the input pulse to which the circuit must respond. If the duration of the input pulse is / (Fig. 2), then during this time the timing capacitor does not have time to discharge to zero, and the blocking generator does not work. If the duration of the input pulse, the timing capacitor has time to discharge to zero, and at the output of the blocking generator a pulse of the output voltage Iyk appears, the duration of which does not depend on the duration of the input pulse, but is determined by the parameters of the blocking generator.

The timed capacitor tends to be recharged to some voltage of opposite polarity exponentially, the portion of which in the region of positive values of 6c is initial and almost linear, which contributes to the stability of the device, configured for a certain duration of input pulses.

The device performs its functions with both single and non-periodic or periodic input voltage pulses, since in the time interval between the right input pulses the capacitor 3 plate through transistor 2 is connected to the source ground to, and the generation conditions are not met.

Subject invention

A pulse selector with a duration that contains an input transistor "pnp" tina, connected according to a common emitter circuit, the collector of which is connected to the output of an integrating capacitor connected by another output via a resistor to the negative pole of the power source, and the blocking generator on the pn -p type, the base of which is connected to a resistive voltage divider connected between the poles of the power source, characterized in that, in order to eliminate the dependence of the duration of the output pulses on the duration Khodnev, the free end of the feedback winding of the blocking oscillator transformer nodsoedinen to the collector of the input transistor.

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