Abstract: A multi-band scanning radio receiver operable without reprogramming in a plurality of geographical regions. Digital codes for public-service-band frequency allocations for each of a plurality of geographical regions are stored in a memory which is sequentially accessed to read the digital codes for the frequency allocations for a selected geographical region. A frequency synthesizer loaded with a digital code read from memory performs band switching and supplies tracking signals and a local oscillator signal to multi-band RF amplifier and mixer circuitry.

Abstract: A radio receiver for use in a vehicle combines a radar receiver, a receiver for the citizen band, and a scanning receiver for public service bands which are controlled in operation and function by a microprocessor. The public service scanning receiver covers a range of public service bands from 37 MHz to 470 MHz. The receiver for the citizen band covers frequencies from 26 to 28 MHz. The radar receiver covers frequencies of traffic radars located in the X and K bands, from 8 to 24 GHz. In the preferred embodiment, a radar detector responds to radar signals in either the X or K band under control of the microprocessor, and is in a standby mode whether or not the operator is listening to reception on the citizen band or a public service band. A synthesizer either selects a desired channel in the citizen band or else scans a preselected group of public service frequencies that correspond to those assigned to a particular state, country or city.

Abstract: An intrinsically safe lighting system for energizing fluorescent lamps and the like in potentially flammable or explosive atmospheres is disclosed wherein one or more intrinsically safe power supply modules embody current monitoring and diverter circuitry, operable, upon the occurrence of abnormal circuit conditions such as a short or open circuit, to interrupt the lamp power supply and divert energy therefrom so rapidly that non-intrinsically safe sparking and ignition of the flammable atmosphere is avoided.