A DEVICE FOR DIGITAL MEASURING OF PULSE RATE

1,243,122. Frequency measuring. TESLA NARODNI PODNIK. 14 Aug., 1969, No. 40729/69. Heading G4H. In a digital frequency measuring system of the type in which a difference signal r (Fig. 5) is derived by a difference circuit 1 from a feedback frequency signal p and the input frequency signal n, the time intervals between pulses of the difference signal are measured, the reciprocals of these intervals being digitally derived in a circuit 3 and accumulated (additively or subtractively) in a circuit 4 controlling a pulse generator 5 delivering the feedback signal p. In the stable condition the state of circuit 4 represents the input. The time intervals between pulses may be determined by counting pulses of known frequency f 0 . A single order counting stage may be used, which when full alters the frequency f 0 by one order. The order of the frequency then determines in which order of the adding circuit the reciprocal of the counter value should be accumulated. If the distribution of the input pulses is not regular, scanning circuit (6, Fig. 6, not shown) may be connected between the input and the differentiating circuit 1 and, if required, between the output of the pulse generator 5 and the circuit 1.