JPS57206873A - Digital counting-rate meter - Google Patents

Abstract

PURPOSE:To accurately find a correct counting rate of an either periodic or random signal and also the momentary change thereof by taking as a counted value the number of waves of the signal within a time which is the sum of a very short time and a fixed time. CONSTITUTION:When an input signal is impressed, an addition-subtraction counting circuit 10 continues the addition counting of the input signal. Meanwhile, a counting circuit 7 repeates an operation of counting the input signal within a clock cycle and delivering a counted value thereof to a temporary memory circuit 9. In the case where the temporary memory circuit 9 is a shift register, the content thereof is delivered sequentially and given, as a subtraction input, to the circuit 10 when the contents reaches the number of the storage capacity of the circuit 9 after the passage of a prescribed time. When the input signal is periodic, the values of addition and subtraction at every clock cycle are the same, and thus a counted value in the circuit 10 reaches a balance. When it is not periodic, the counted value in the circuit 10 changes at the clock cycle. In measuring a random signal, a standard deviation can be reduced by increasing the storage capacity of the circuit 9.