Voltage instantaneous frequency digital measuring cct - has first comparator for D.C. voltage corresponding to instantaneous frequency

摘要

The d.c. voltage corresponding to instantaneous frequency is compared with an adjustable auxiliary voltage, and its pulse at equality of both voltages determines the measurement instant. The d.c. voltage is derived from the instantaneous frequency through a frequency-voltage convertor, which comprises a capacitor periodically charged with a constant charge at the instantaneous frequency, and continuously discharged through a resistor. The above d.c. voltage appears at its terminals as the mean voltage. A second comparator compares the adjustable reference voltage with a stepped voltage derived from a fixed frequency generator through a circuit corresponding to the frequency voltage comparator, but without the resistor.