SU966660A1 - Device for measuring short pulse duration - Google Patents

Description

t

The invention relates to automation and computing and is intended for precision digital measurements of the duration of short pulses.

It is known that a device for measuring time intervals, based on a comparative change method, contains two generators, two counters, and a code comparison unit.

The device works as follows.

At the beginning of the time interval, a sequence of pulses with a frequency f is received. To the input of the main pulse counter, and since the end of the time interval, an additional counter receives a sequence of pulses having a frequency slightly greater than f. As soon as the number of pulses recorded in the main and additional counters becomes the same, the counting stops and this number is recorded as a result of measuring the time interval 1.

The drawback of the device is a large pulse duration measurement time, linearly dependent on the measurement accuracy.

Claims (3)

A device for the vernier time interval measurement, comprising a quantizing and vernier generators, an advance discriminator, a logic unit and a transmission unit, is known. The pulse of the beginning of the measured interval includes a quantizing generator, the pulses of which are fed to the input of the discriminator advance and through the transmission unit to the output of the device for counting the number of quantizing periods of the pulse. to the second output of the device for counting the number of the Vernier periods p. At the moment of arrival of the first pulse of the Vernier generator, the advance discriminator determines the queue it arrives in relation to the pulses of a quantizing series, and the logic unit closes the transmission block, passing at the output n pulses of the quantizing series, which came before the first pulse of the non-neural generator. After m periods of the vernier generator, the order of arrival of the pulses of the two generators on the advance discriminator changes. This will register the discriminator and the logic circuit to install both oscillators 2. The disadvantage of this device is the need to synchronize the generators with input effects, which leads to a deterioration of the generator stability and a decrease in the accuracy of the device. The closest in technical terms to the present invention is a pulse extender comprising charge and discharge generators, a switch, a capacitor, and a relay element. The device operation principle consists in the fact that during the time the pulse is acted upon by the discharge current, the capacitor discharges to a voltage that is proportional to the duration of the input pulse, and at the end of the pulse a much smaller charge current determines the accuracy of the measurement. value. The beginning of the expanded pulse coincides with the beginning of the input pulse, and the end with the moment when the voltage on the capacitance reaches its initial value of 3. However, this device has a long pulse duration measurement time, linearly dependent on the measurement accuracy. The purpose of the invention is to reduce the measurement time of the pulse duration. The goal is achieved by the fact that a device containing a charge and discharge generators, a capacitor and a zero-organ, whose input is connected to the outputs of the charge and discharge generators and one of the capacitor plates, the second plate of which is connected to the common bus, is input bus the device is connected to the input of the charge generator; a threshold element, a discharge generator, a synchronization unit and two pulse counters are additionally introduced, the first input of the synchronization unit is connected to the input bus of the device, the second input is connected to the output of the threshold element The input of which is connected to the output of the additional generator of the discharge and the input of the zero-organ, the output of which is connected to the third input of the synchronization unit, the fourth input of which is connected to the counting inputs of the first and second pulse counters and the reference frequency bus, To the input of the generator of the discharge, the second output to the input of the additional generator of the discharge and the third and fourth outputs are connected to the control inputs of the first and second pulse counters, respectively, whose outputs are output ami device. FIG. 1 shows a block diagram of the device; in fig. 2 - temporary) 1 diagrams, which explain his work. The device contains a charge generator 1, generators 2 and 3 bits, a threshold element 4, a zero-body 5, a capacitor 6, a synchronization unit 7, counters 8 and 9 pulses. The device works as follows. A pulse arriving at the device input (Fig. 26), through synchronization unit 7, shuts off the discharge current of the generator 3, and through the charge generator I charges the capacitor 6 to a voltage proportional to the duration of the input pulse (Fig. 2c). After the end of the input pulse, the charge of the capacitor 6 stops and the synchronization unit 7 on the leading edge of the first reference frequency pulse (Fig. 2a) turns on the discharge currents of the interactors 2 and 3 (Fig. 2 g, d) and resolves the next pulse series write to the first counter 8 pulses (Fig. 1 g). When the voltage of capacitor 6 drops below a smooth level, the threshold, threshold element 4 will work and the leading edge of the next reference frequency pulse will then be written into the first pulse counter 8 (Fig. 2) and through synchronization unit 7 will turn off the generator 2 current (Fig 2d), rewrites the current value of the counter 8 pulses to the output register of this counter, resets it and allows writing the next series of pulses of the reference frequency to the counter 9 pulses (Fig. 2 and). When the voltage on the capacitor 6 drops to zero (Fig. 2c), the zero-organ 5 changes its state (Fig. 2e), through the synchronization unit 7 it stops the access of the reference frequency pulses to the counter 9 of pulses (Fig. 2i), overwrites the current value counter 9 pulses into the output register of this counter, will reset it and, due to nonlinear feedback, will compensate the discharge current of generator 3, maintaining the voltage on the capacitor 6 equal to zero. This completes the measurement cycle. If during the charging of capacitor 6, the voltage does not reach the Unop value (Fig. 2c), then the 2 discharge generator at the end of the input pulse does not turn on and at the end of the measurement cycle the output register of the pulse counter 8 turns to zero. The Unop value is chosen such that the combined effect of the discharge currents of two generators 2 and 3 during the reference frequency period cannot discharge the capacitor 6 from the Unop value to zero. The choice of specific magnitudes of charge and discharge currents, as well as the magnitude of the threshold voltage, depends on the range of measurement of the duration of the input pulse and the period of the reference frequency. Apparatus of the Invention A device for measuring the duration of short pulses, containing a charge and discharge generator, a capacitor and a zero-organ whose input is connected to the outputs of the charge and discharge generators and one of the capacitor plates, the second plate of which is connected to the common bus, ; the devices are connected to the input of the charge generator, characterized in that, in order to reduce the measurement time of the pulse duration, a threshold element, a discharge generator, a synchronization unit and two counters are additionally introduced into it; pulses, the first input of the synchronization unit is connected to the input bus of the device} the second input - to the output of the threshold element, the input of which is connected to the output of the additional generator of the discharge and the input of the zero-organ, the output of which is connected to the third input of the synchronization unit, the quarter input connected to the counting inputs of the first and second pulse counters and the frequency reference bus, the first output of the synchronization unit is connected to the input of the discharge generator, the second output is connected to the input of the additional discharge generator, and the third and The fourth outputs are connected to the control inputs of the first and second pulse counters, respectively, the outputs of which are the outputs of the device. Information bristles taken into account in the examination 1. USSR certificate If If 363068 USSR, cl. G 06 F 10/04, 1973. 2. USSR author's certificate Vf 538335, cl. G 04 F 10/04, 1977. 3. USSR author's certificate fP 585596, cl. H 03 K 5/04, 1977. M I I M $ 1