A Portable Microwave Phase and Amplitude Test Set

Phase alignment at microwave frequencies may be made to 0.1° or less, and amplitude balance to 0.1 dB may be made simultaneously with this fully solid-state test set which is designed to be comparable in size and weight to a Tektronix oscilloscope. Provisions are incorporated for testing with either pulsed or CW signals. Present means of measuring phase and amplitude differences at microwave frequencies require either rack size equipments or a group of various pieces of test equipment such as RF generators, standing wave indicators, and slotted lines. Standard procedures are to utilize slotted lines with VSWR sampling points using a short-circuited line or line-swapping arrangement. While these methods are versatile, all have limitations in resolution and accuracy while requiring long setup times and a high degree of skill by the operator. Operating at a single-crystal-controlled microwave frequency, this test set provides a means of continuously comparing two signals, one a reference or standard; the other a signal to be adjusted. The phase and amplitude difference between these two signals may be reduced to a null by adjusting the module under test while observing two zero-center balance meters. The signals may be read to ±3 dB and ±3.0° or ±90° full scale. Accuracy is better than 5 per cent for all scales, and the null resolution is ±0.05 dB and ±0.05°. A self-contained solid-state reference signal generator produces up to 3-watts power output from a balanced varactor double stage at 1296 Mc.