| 摘要 |
A radio direction finder, designed to determine the direction of arrival of radio waves utilizing a nondirectional antenna and a plurality of directional antennas having respective directivities, comprises an oscillator for producing A.C. signals having a phase angle in correspondence to the configuration of each of the directional antennas, modulators for modulating the respective outputs of the directional antennas with respective A.C. signals, a additive circuit for superimposing the respective modulation outputs on the phase-shifted output of the nondirectional antenna, and a receiving circuit for demodulating the added output of the additive circuit to recover the A.C. signals. The radio direction finder is further characterized by an automatic phase tracking counter for following the phase of the output of the receiving circuit, and a display unit for displaying the bearing of the received radio wave numerically. Special circuitry is provided for achieving accelerated automatic phase tracking, for stopping the automatic phase tracking procedure upon the occurrence of certain disturbances, and for restarting the procedure upon disappearance of the disturbances.
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