Wideband Precision Phase Detector

A phase error detecting system designed for the RF system of the 3-Bev Princeton-Pennsylvania Proton Synchrotron is described. It serves as a link in the servo loop to keep ferrite tuned RF load to track the driving signal which sweeps from 2.5 to 30 mc/s at repetition rate of 20 cps. The input signals are shifted to a constant intermediate frequency of 455 kc/s by mixing with a specially generated tracking signal. Limiting, phase shifting, and the phase detection are all done at 455 kc/s. Its output phase lag for phase modulation frequency below 50 kc/s is less than 90°. It has a usable range of 40 db input variation. Zero output accuracy is ± 2° for the range of 20 db input variation. All circuits, except the tracking signal generator are transistorized.