Non-linear function generator

Abstract

A function generator for producing digital data which represent a function of the time interval between two events and in which the digital data have a non-linear relationship to the time interval. The function generator comprises a rate multiplier circuit having a constant pulse frequency multiplicand and a continuously varying multiplier selected by a memory circuit throughout the time interval. A counter circuit has its input connected to the output of the rate multiplier circuit and has its output connected to the memory circuit to continuously address the memory circuit for selecting the continuously varying multiplier as each output pulse from the rate multiplier circuit is counted by the counter circuit. The data stored in the memory circuit for selecting the multiplier represents a series of straight line approximations to the desired continuous non-linear function. A digital feedback loop is formed between the rate multiplier circuit, the counter circuit and the memory circuit to cause a non-linear function to be generated by two events defining a time interval. At the completion of the time interval, the total count of pulses applied to the counter circuit is registered in a data storage device to provide digital data which represent a non-linear function of the time interval between two events.