Pre-conditioner for measuring high-speed time intervals over a low-bandwidth path

Abstract

A pre-conditioner for enabling high-speed time interval measurements in an ATE system having a relatively low-bandwidth pathway between a UUT and a timer/counter includes a frequency divider and a D flip-flop located near the UUT. The frequency divider receives a first input signal from the UUT and produces a first output signal having a frequency equal to 1/N times the frequency of the first input signal. The first output signal connects over the low-bandwidth pathway to a first channel of the timer/counter. The first output signal also connects to the D input of the D flip-flop. The pre-conditioner receives a second input signal from the UUT that drives the CLOCK input of the D flip-flop. The Q output of the D flip-flop supplies a second output of the pre-conditioner. The second output connects over the low-bandwidth pathway to a second channel of the timer/counter. The time interval between successive rising edges of the output signals precisely match the time interval between successive rising edges of the input signals. Although the pre-conditioner preserves the edge locations of its input signals, the frequency of the signals it sends to the timer/counter is 1/N times the input frequency. The pre-conditioner thus enables to the timer/counter to measure closely spaced, consecutive edges of inputs over a low-bandwidth path. Multiplexors, inverters, and additional frequency dividers may be included with the pre-conditioner to enhance its functionality.