Pilot-Subcarrier Phase Measurements in Stereophonic Broadcasting

In VHF FM stereophonic broadcasting, the 19-kHz pilot subcarrier is transmitted with prescribed phase related to the 38-kHz stereophonic subcarrier. A small phase departure tolerance is desirable to avoid crosstalk. The present paper describes a method and an instrument suitable for simple measuring and checking of the pilot-subcarrier phase departure. Monitoring during regular broadcast is also possible. The accuracy of the phase departure measurement is better then 0.5°and the calibration of the instrument does not require an oscilloscope or any additional instrument.