A Scanner for Rapid Measurement of Envelope Delay Distortion

A measuring device is described which instantaneously displays the envelope delay-frequency characteristic on a cathode-ray screen. Loop and one-way measurements of long-distance radio networks can be carried out. The frequency range extends from 60 to 80 megacycles; the limits of accuracy are 1 millimicrosecond or 2 per cent of the measured delay range. Comparison of two characteristics can be carried out by superposition of alternate scanning traces. The device has been found useful in measuring the delay distortion of the TD-2 radio-relay system and in designing and adjusting the delay equalizers needed to correct it.