Abstract: A two-way business-band transceiver for operation on an assigned FCC frequency includes a chassis housing a plurality of printed circuit boards which are surrounded by a three-part enclosure. This enclosure includes a main body portion having a top half and a bottom half and a control head portion which is separable from the main body portion. The transceiver circuitry which is arranged both within the main body portion as well as within the control head portion includes frequency synthesizing means which are selectable yet nonaccessible from the front of the control head portion. Frequency selection is accomplished by gaining access to a programming circuit portion which is located within the control head portion. This programming circuit portion includes a plurality of 10-position, rotary BCD switches which are arranged for channel 1 and channel 2 operation.

Abstract: A portable transceiver includes a two-piece transceiver housing which encloses a double-sided printed circuit board. The transceiver housing includes a front surface portion and a control panel portion which is integral with, but recessed below, the front surface portion. Within the control panel portion are four clearance apertures which provide operator access to the operator controls of the printed circuit board. The width and depth of the housing are suitably sized to enable the portable transceiver to be hand held in one hand while the thumb of that same hand is able to manipulate the various operator controls. These controls protrude through the various clearance apertures yet the outermost portions of the controls remain flush with to recessed below the front surface portion. The printed circuit board is a self-contained transceiver such that all wiring is completed prior to installing the printed circuit board into the transceiver housing.

Abstract: A modular aviation NAV/COM radio which is adapted for different mounting orientations and is thereby suitable for use on a variety of aircraft includes an OBS converter-indicator which is removable from the main body receiver portion. The OBS converter-indicator is able to be mounted separately from the main body receiver portion so that it can be positioned directly in front of the pilot when cockpit space is not available to mount the entire radio directly in front of the pilot.

Abstract: A keyboard entry VOR receiver incorporating a phase locked loop frequency synthesizer under processor control is disclosed. In one version a scanning VOR navigation receiver with a multitude of VOR displays operating from that one receiver and under the control of the processor also includes a keyboard for operator entry of information into the processor and a display for viewing frequency and other information during operation of the receiver. The processing means includes a central processing unit, keyboard and display interface circuitry, general input and output circuits and a memory. The display may be a conventional omni bearing selector and course deviation meter arrangement or a plurality of three digit bearing displays may be employed.

Abstract: A transceiver channel selection circuit operable in both transmit and receive modes of operation including a digital phase lock circuit having a controllable oscillator, a reference frequency source, and means for obtaining a signal, the frequency of which is an aliquot part of the controllable oscillator frequency, are connected together in a feedback loop and the reference frequency and submultiple frequency compared and the controllable oscillator frequency changed, if the submultiple and reference frequencies differ.

Abstract: A network for connecting a receiver and a transmitter to a common antenna to utilize the antenna for both transmit and receive modes of operation is disclosed, which network is suitable for either relay antenna switching or solid state antenna switching. The network includes a band pass filter coupling the transmitter output to the antenna at least during the transmit mode of operation and first and second filter junction points for coupling the antenna to the receiver. One of the first and second junction points is coupled to the receiver at least during the receive mode of operation, and includes means for inhibiting the application of the transmitter output signal to the receiver during the transmit mode of operation.

Abstract: A modular radio, adapted for different mounting orientations and thereby suitable for use on a variety of water and air crafts. One embodiment pertaining to marine radios includes a head which is removable from the main body and a control panel which is detachable from the head. The main body can be secured within the vessel at virtually any height by means of a U-shaped bracket. When the radio is approximately waist high, the head and control panel are arranged so that the controls read left to right and are in an upwardly-facing orientation, normal to the user's line of sight. When the radio is mounted overhead, the head and control panel are arranged so that the controls read left to right and are in a downwardly-facing orientation, normal to the user's line of sight. The head and main body are adapted to be mounted to the vessel separately from one another. Another embodiment, pertaining to aviation radios, includes a converter indicator which is removable from the main body portion.

Abstract: A voltage variable filter circuit useful, for example, in a radio frequency transmitting device and having a center frequency which is changeable with changes in an applied voltage employs one or more voltage variable reactive elements in the filter in conjunction with circuitry for changing the direct current voltage across such reactive elements to change the reactance thereof and therefore also change the center frequency of the filter. To extend the range of filter variation, additional reactance may be selectively introduced into the filter circuit. In the environment of a multi-channel radio frequency transmitting device, a selector switch simultaneously selects one radio frequency channel for transmission and a unique voltage source for application to the voltage variable reactance so that the filter is appropriately tuned for the selected channel.