A MULTIPLEX ADAPTER DESIGN USING A BALANCED SQUARE LAW PRODUCT DETECTOR
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Since the approval of a FM stereophonic broadcasting system by the Federal Communication Commission in 1961, the audio industry has discussed two general methods of separating the two stereophonic signals-by matrixing techniques and by time-multiplexing techniques. The purpose of this paper is to present a third method--a product detection technique. By using uniquely designed Balanced Square Law Product Detector which produces no linear amplification, it is possible to extract the difference channel without the use of any filters. A system which can extract this difference channel without the use of filters is greatly desired because using any type of filter will greatly lower the separation between the two stereophonic channels. As a further modification of the product detector technique, an examination of synchronous detection using the product detector technique is made, thereby eliminating the need for the 19,000 cycle pilot subcarrier which at times has a tendency to jitter or phase vary.
- Radio Communications