Quasi-coherent synchronisation of two different frequencies - measuring sinusoidal signal frequency and comparing with reference frequency related to both input frequencies

摘要

The process measures a frequency (f1) of a sinusoidal signal and compares it with a rated reference frequency (fN). The latter corresponds to a mean frequency between those (f1, 2) of two input signals (sf1, 2), to obtain a shift frequency (fv) with a corresp. sign. A VCO (5) with a frequency, corresp. to the mean frequency, is brought into oscillation at a specified, related frequency. The first two frequencies (f1, 2), as a mirror-image of the reference frequency, are applied to a phase comparator (9) via controlled gate circuits (7, 8) after time intervals (T), inversely proportional to twice absolute shift frequency. The comparator output voltage is at times proportional to the difference between the first two frequencies. USE/ADVANTAGE - For navigation satellites, with precise distance measuring, and time signal transmission.