Goniometer circuit for VOR system

摘要

The present invention relates to an improved goniometer circuit having extremely low modulation harmonic distortion characteristics, which is particularly suitable for use in a VOR navigation system. In the disclosed circuit, modulation harmonic distortion is greatly reduced by the use of a phase lock loop operating at small signal levels prior to the power amplification stage of the system. The phase lock loop employs a voltage controlled oscillator to completely eliminate harmonic distortion so that the final output of the system is virtually modulation free.