Abstract: A microprocessor control unit (MCU) is mounted on a printed circuit board. The MCU includes first and second clocked serial interface (CSI) circuits. The first CSI circuit is configured to serially transmit a first xCP packet to a first encoder circuit, which in turn is configured to generate an encoded first xCP packet as a function of the first xCP packet and a first clock signal. A first low voltage differential signal (LVDS) circuit is coupled to the first encoder circuit and configured to serially receive the encoded first xCP packet therefrom. The first LVDS circuit is configured to generate a first differential signal as a function of the encoded first xCP packet.

Abstract: A microprocessor control unit (MCU) is mounted on a printed circuit board. The MCU includes first and second clocked serial interface (CSI) circuits. The first CSI circuit is configured to serially transmit a first xCP packet to a first encoder circuit, which in turn is configured to generate an encoded first xCP packet as a function of the first xCP packet and a first clock signal. A first low voltage differential signal (LVDS) circuit is coupled to the first encoder circuit and configured to serially receive the encoded first xCP packet therefrom. The first LVDS circuit is configured to generate a first differential signal as a function of the encoded first xCP packet.

Abstract: A method for computer memory calibration includes flashing a calibration from a processor into two flash memory sections. Either the same or an alternate processor requests data stored in one of the flash memory sections. Subsequently, exception handler logic within an exception mechanism activates and generates an exception for the data stored in the aforementioned flash memory section. The calibration in the other flash memory section then transfers to the processor through the functioning of the exception.

Abstract: A transceiver that allows scanning to occur with the microphone in an off hook position. The transceiver includes a main unit, external microphone, and hook for holding the microphone. The external microphone includes a push-to-talk button, which may be pressed in order to allow audio signals to be converted into electrical talk signals and sent to the main unit. The main unit scans a plurality of channels according to a predetermined sequence. One channel is designated as a "priority" channel. Scanning continues when the microphone is off hook. When the unit detects channel activity on a specific channel that it is monitoring at a particular time, it discontinues the scanning both during the channel activity and for a predetermined wait period after the absence of such activity on the specific channel. Should a talk signal occur within the wait period following activity on the specific channel, the talk signal is processed on the specific channel.

Abstract: Self-programming scanning receiver having superheterodyne circuitry, microprocessor controlled synthesized frequency tuning circuitry, frequency validation means, a learn mode to invoke the frequency validation means for all frequencies tunable by the tuning circuitry, listen mode for scanning of frequencies learned in the learn mode, and an ignore mode for erasing frequencies from permanent memory.

Abstract: A high-speed, multi-band scanning radio receiver. 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. An output of an FM detector in the receiver is connected to a squelch circuit which includes a high-pass filter network and a diode detector, with the diode detector output being connected to an internal A/D converter of a microprocessor which converts multiple samples of the incoming signal to digital values and generates a mute signal when the average value of the converted samples is below a predetermined squelch level. An output line from the FM detector to audio output circuitry in the receiver is grounded in response to the mute signal.

Abstract: A rapid scanning radio with multi-mode local oscillator control. In one embodiment a phase-locked loop is closed for tuning to all frequencies of interest, and each time the loop locks a DAC is loaded with successive digital values until a value corresponding to the steady-state VCO tuning voltage is found for the currently tuned channel. That digital value is stored for later recall as the tuning value for that channel. Once digital values are determined for all the tunable frequencies in the radio, the loop is opened for high-speed scanning under open-loop control of the DAC.

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.