Abstract: A key activated switch matrix on a mother board that enables a dedicated key when inserted to select a subset of selectable parameters and thereby configure the mother board without further operator intervention. A housing having a slot is positioned on the mother board. An array of conductor pairs is positioned in the slot one element of each pair on either side of the slot with one end of each element of a conductor pair extending through the bottom of the housing to make electrical contact with wiring of the mother board and the other end of each element formed so as to make contact with its mating conductor element. A key is provided that consists of a single electrically insulating body having dimensions for fitting into the slot between the pairs of conductor elements and allowing certain of the conductor pairs to make electrical contact and precluding other pairs from making contact.

Abstract: A multicoupler for use in interfacing multiple frequency-agile transceivers to a single antenna. The multicoupler includes a set of high-Q filters and a switching matrix for selectively connecting the transceivers to the filters. The filters have frequency shift capabilities so that a broad frequency range can be covered by a limited number of filter units. The switching matrix is adapted for connecting any one of the transceivers to any one of the filters in accordance with the operative frequencies of the transceivers and filters. The structure of the multicoupler enables it to rapidly track frequency hopping patterns executed by the transceivers while providing good isolation between the transceivers and producing limited amounts of intermodulation distortion.

Abstract: A network is coupled to the gate electrode of a FET for generating a negative gate electrode voltage having a selected nominal value for minimizing intermodulation distortion of the FET and/or a value varying with respect to the nominal value directly proportional to temperature changes to provide a constant gain for the FET.