Radio direction finding system using loop aerials - uses search coil goniometer and phase shift networks

摘要

The radio direction finding system comprises two crossed-loop aerials (1, 2) whose signals are converted (3) and amplified. The output of each channel amplifier (4, 5) is a voltage whose amplitude is proportion to the sine and cosine respectively of the angle of incidence of the received signal. A search goniometer (6) is connected to a signal generator (7) and the pick-up coil output is filtered to extract frequencies of twice the oscillator frequency. This signal passes through phase detector (10, 11) and integrating circuits to the output terminals (19, 20). - One of the detectors is fed with a 90 deg. phase-shifted signal from a frequency-doubler (12) and the other detector from a 180 deg. phase-shifted signal or directly from the doubler by a switching circuit (15).