Leonard Kahn had an article in the 1960 NAB Engineering Handbook about Full Carrier Compatible Single Side Band. It was used to lessen adjacent channel interference between WINS, KDKA, and WBZ. Nothing new under the sun I guess. In that article, he discussed how the single sideband phase modulated the full carrier. It was in a way that could be represented as a spinning vector from the carrier vector going CW or CCW depending on whether it was USB or LSB that was used. Hence if there was both a USB equal to the LSB there was no phase modulation. If USB and LSB were not the same, they HAD to phase modulate the carrier in some way. I think that this was the "secret" that Leonard Kahn used to talk about that allowed other AM stereo detectors to detect the Kahn system. All that was needed was the pilot added, which accidentally happened from difference frequencies between pure audio sine components and intermodulation of audio frequencies. All that had to happen was it to persist long enough to activate the detector. Meanwhile, Leonard Kahn maintained that it was not based on phase modulation, that the sidebands were completely independent. But R-L had to phase modulate the carrier. Not sure about the linearity, but I suspect it was quite linear also.
Anyone have another theory or explanation?
Anyone have another theory or explanation?
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