Checking circuit for radar beam accuracy - examines phase difference between two signals for typical value of position

摘要

The control circuit is for checking the accuracy of a commutated radar beam. The aerial is used in an approach and landing control system for aircraft. The variation w.r.t. time of the phase difference between a first signal and a second signal is determined and the occurrence of a given phase difference which typifies a predetermined position of the scanning beam is examined. Random samples are taken from the first signal at a point in a region where the field generated by the aerial is always present during the excitation. The observation of the occurrence of a phase difference is done by comparing a signal indicative of the phase difference between the two signals with a signal indicative of the phase difference between the two signals which occurs when the aerial operates with a zero direction fault.