Abstract: In a remote-control communication system, a signal generating unit includes a first signal transmitter for transmitting a first signal at a first frequency, such as UHF, a second signal transmitter for transmitting a second signal at a second frequency, such as an infrared frequency, that is diverse from the first frequency; a keyboard for generating an information signal containing a given message, which is modulated onto both the first signal and the second signal; wherein both the first and second modulated signals are transmitted in response to a key of the keyboard being pressed to generate the information signal. A receiver for the system includes a microcontroller for processing the given message to control a given operation of an electronic communication apparatus; a UHF detector and demodulator unit and an infrared detector and demodulator unit, which respectively detect and demodulate the first and second modulated signals to provide the information signal containing the given message.

Abstract: A frequency synthesizer includes a voltage-controlled oscillator (VCO) for producing a VCO output signal within a given frequency range, wherein the VCO produces the VCO output signal at a predetermined frequency in response to an analog VCO control signal that indicates the predetermined frequency; a microcontroller for processing a frequency measurement value with a reference value to provide a digital VCO control signal that indicates the value of the analog VCO control signal required for causing the VCO to produce the VCO output signal at the predetermined frequency and for pulse-width-modulating the digital VCO control signal; and a low-pass filter for converting the pulse-width modulated VCO control signal into the analog VCO control signal.

Abstract: In an RF receiver having a phase-locked loop demodulator and FLL tuning in its RF converter, the frequency of the VCO output signal in the phase-locked loop (PLL) demodulator is controlled indirectly by the FLL in the RF converter in response to a measurement of the VCO output signal in the phase-locked loop demodulator and comparison of such measured signal to a predetermined intermediated frequency. A microcomputer performs a refined FLL tuning algorithm to tune a selected RF carrier input signal and audio subcarrier input signals. The algorithm provides a means of assuring that the PLL demodulator is responding to an input signal derived from a carrier signal of a selected input frequency without having to use hardware to detect the presence of a carrier signal.

Abstract: An interface permits bi-directional data signal transfer between the microcomputer of the receiver and an addressable controller-decoder designed for use in conjunction therewith. The data transfer permits expansion of the receiver functions and future adaptability to a variety of satellite services. The interface transfers messages from the microcomputer representing keystrokes received from the receiver keyboard and the status of the various receiver components and receives commands from the decoder for regulating the operation of the receiver components and for the transfer of specific information. The data transfer is achieved through a serial communication protocol which facilitates the interaction between units.