USA As Represented by Secretary of the Navy

Robert E Hunt

Kenneth L Moore

David J White

Ralph K Beyer

Carl N Helmick, Jr

A method and apparatus are provided for passive direction finding that demines the sideband and angle of arrival of an incoming radio signal. A four-channel superheterodyne receiver generates quadrature between the radio signals received by each channel. Four inphase/quadrature phase detectors are connected to the receiver for generating inphase and quadrature components of the electrical phase differences between antenna elements of the receiver. The inphase and quadrature components are used for sideband determination and the electrical phase differences are used to derive the angle of arrival.

Method and apparatus for passive direction finding with sideband

A method and device for adjusting the center frequency after fabrication of surface acoustic wave (SAW) devices by the deposition of a nonconducting coating which alters the SAW propagation velocity of the device.

Method and materials for tuning the center frequency of narrow-band

A method of producing an optical reticle and the reticle produced thereby. thin layer of aluminum is deposited on the face of a sapphire substrate and a reticle pattern is chemically etched therein. The system is then exposed to air at an elevated temperature for approximately one hour to oxidize the remaining aluminum layer. A film of titanium is next placed over the rough aluminum oxide as by sputtering, for example, and the excess titanium is etched away by the same pattern to produce the finished reticle.

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Ridgecrest, CA, United States of America

Robert E Hunt