Delco Electronics Corporation

Barry F Koch

Richard A Kennedy

An FM stereo receiving system and a method for aligning phases of RF signals received by multiple antennas. The FM stereo receiving system includes two antennas for receiving RF signals having a common frequency but potentially different phases. The system also includes an FM receiver having a detector output and a pilot output on which a pilot tone, such as a 19 kHz pilot tone, is present. A summer is included in the system for summing the RF signals and providing the summed signal to the receiver. The amplitude modulator of the system resides between one of the antennas and the summer to amplitude modulate the antenna's RF signal at a perturbation frequency which is a whole number multiple greater than 1 of the pilot tone. The receiver thus produces on its phase detector output a phase signal having a frequency equal to the perturbation frequency and a magnitude corresponding to the phase error between the RF signals which is connected in a feedback loop to align the phases.

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Kokomo, IN, United States of America

Barry F Koch