Universal Microwave Phase-Measuring System

A 70-GHz microwave phase-measuring system, capable of detecting small as well as multiradian phase changes, is described. The use of programmable, digital dividing circuits permits phase changes of up to 20 π radians to be measured without ambiguity. A 2μs rise time of system output permits rapid phase changes to be detected. The output voltage, which is directly proportional to phase change, can also be monitored by a digital voltmeter or a chart recorder for long time measurements. Signal limiting makes the measurement relatively insensitive to a 20-dB change in microwave signal level.