SU398961A1 - DEVICE FOR DIFFERENTIATING AC SIGNALS - Google Patents

Description

The invention relates to computing.

Devices for differentiating alternating current signals are known, comprising an operational amplifier with a parallel-connected air-conditioner and a key in the feedback circuit and an input air-conditioner, connected via another key to the input signal source.

All known devices are not enough} 10 accurate.

The proposed device is characterized in that it contains an additional key included between an input candeisator and an inverted signal source.

This has improved the accuracy of the device.

The drawing shows a diagram of the device.

The electronic key / briefly connects the capacitor 2 to the source 3 of the input signal one time during the period of the alternating current at the moment when the signal reaches the amplitude value. Since the potential of the input of the operational amplifier is always practically equal to zero, and on the capacitor 2, the envelope of the input signal is remembered as a step function, the values of which change once during the period of closing the switch /. The electronic switch 5 is closed for a short time, but with the advance of the switch / for a time over the lock, discharging the capacitor 6 to zero. At the time of the key / capacitor 6 closure is charged with a current equal in magnitude and opposite in sign to the overcharging current of capacitor 2, remember the voltage, rabbiot (with equal capacitances of the condensers 2 and 6) or proportional to the increment of the voltage on the capacitor plates 2. Thus, the output of the amplifier 4 is derived

envelope of the input signal amplitudes in the form of a step function, the values of which change discretely at the closing point and key 1, and before that briefly drop to zero at the closing point of key 5 (constant times of charge and discharge circuits of condetator 2 and 6 must be 3 times shorter than the closure of the keys / and 5). This “april tion to be modulated in modulator 7, to which (as well as to the circuit

key management) is squared) {AC reference signal. Modulation by a quadrature signal allows one to obtain a nearly harmonic current, since the moments of the discharges and charges of the capacitor

6 coincide with the transition of the reference signal through “ul.

The reduction of the equivalent time lag to a 0.25 AC period is provided by introducing into the circuit an additional switch 8 connected to the source 3 of the inverting input: a new signal (to the second input winding of the tramformator). The keys I 1 and 8 work at the same time, each with the frequency of the alternating current, and the key 5 with the double frequency.

SUMMARY OF THE INVENTION

Y | STIRO1SFVO for differentiating the signals of the intermittent current containing an opamp; here the amplifier with a parallel connected by the indenter and the key in the feedback circuit and the input capacitor connected through another key to the external sypnal, characterized by the fact that, in order to improve the accuracy of device, it contains an additional key, 1 key between the input capacitor and the source of the input signal.