A Swept-Frequency 3-Centimeter Impedance Indicator

An item of test equipment is described which is capable of presenting on a cathode-ray tube sufficient information to determine the magnitude and phase of the impedance of a load at a number of closely spaced frequencies over a 12 per cent frequency range centered in the 3-cm band. The fist model of the equipment measures reflection coefficients with an accuracy, for low standing-wave ratios,. of ± 4° in phase and ±8 per cent in magnitude. A novel rf circuit, called a wave sampler, makes the accuracy of this system independent of frequency.