An accurate logarithmic ratemeter for random pulses

Abstract

This paper describes a new principle of obtaining an accurate wide range logarithmic response to random pulse rates. The logarithmic law is achieved by summing the averaged outputs of a chain of flip-flops which are all set (or reset) by the common train of random input pulses and which are reset (or set) by different but related clock rates obtained from clock frequency divider circuits. A practical log-ratemeter is described which utilises this principle and which illustrates the inherent simplicity, stability, wide range potential and designability of the circuit involved. This ratemeter uses Transistor Transistor Logic and covers the range 1 to 10⁷ counts per second.