GB1470660A

GB1470660A - Time interval measurement

Info

Publication number: GB1470660A
Application number: GB5062073A
Authority: GB
Original assignee: British Aircraft Corp Ltd
Current assignee: British Aircraft Corp Ltd
Priority date: 1974-11-15
Filing date: 1974-11-15
Publication date: 1977-04-21

Abstract

1470660 Measuring times between pulse centres BRITISH AIRCRAFT CORP Ltd 15 Nov 1974 [31 Oct 1973] 50620/73 Heading G1U In a system for measuring the time between the occurrence of the centres of two pulses or for measuring some function of the times between the centres of a plurality of pairs of pulses, a reference signal is caused either to increase or to decrease at each beginning and end of each pulse at a rate of either zero, x, or 2x. Several examples of the principle employed are described. In the first, Fig. 1, for measuring the time between the centres of two pulses, a reference signal Vo is caused to increase, at the beginning of the first pulse, at a rate x, to continue increasing at the end of the first pulse but at a rate 2x, to revert to the rate x at the beginning of the second pulse, and to remain constant from the end of the second pulse onwards. It then follows that the total rise in level of the reference signal from Vo to VF is proportional to half the sum of the durations of the two pulses plus the time between them, i.e., proportional to t 1 the time between the pulse centres. In a second example, Fig. 2, for measuring the difference between the time t 1 between the centres of the first two of three pulses and the time t 2 between the centres of the second two of the three pulses, a reference signal is varied as shown, and it follows that the net change in the reference level from Vo to VF is proportional to the desired time t 1 -t 2 . In a circuit, Fig. 5, for implementing this example, a counter 12 is stepped by a threshold detector 10 at the beginning and end of each pulse to cause a control circuit 16, 18 to drive an integrator 20 appropriately, the output of the integrator being sampled and held at the end of the sequence. Further more complicated examples are described, and it is observed that each pulse could be a burst of closely spaced short-pulses, the gaps between the short pulses being filled-in by an appropriate monostable circuit.