U.S. Philips Corporation

Airbus Operations Gmbh

Burkhard Heinke

Christian Wiese

Marcus Smidt

The invention relates to a communication system and a method for controlling a communication system for communicating audio data between each of a plurality of terminal units (T-T). In order to provide a deterministic communication protocol with lowest possible overhead and a system for implementing same said method is characterized by the steps of: examining an identity of said terminal units (T-T) by said central unit () during an initialization phase; transmitting a predetermined data frame including a first synchronization signal, a terminal unit address of a respective terminal unit, a payload field and a second synchronization signal by said central unit () via said master bus () during a configuration phase; and transmitting audio data through said data bus () by one of said plurality of terminal units (T-T) within an audio sample time interval that corresponds to the interval between said first synchronization signal and said second synchronization signal.

Deterministic communication system

For a possible simple structure, dispensing with ceramic filters, an FM demodulator for demodulating sound-FM signals comprises a controllable amplifier (1) which receives the sound signals converted to intermediate frequencies, said amplifier having a gain which is adjusted by means of an amplitude control circuit (4) and whose output signal is applied to the amplitude control circuit and to the phase-locked loop which supplies a demodulated sound signal in the locked-in state from its output, said phase-locked loop including a loop filter (7) which comprises a filter (8, 9, 10) of at least the second order with a pole at the frequency f=0, and a limit-detection circuit (13) which feeds back the operating frequency of the phase-locked loop to a predetermined frequency range when said phase-locked loop leaves this frequency range around a predeterminable nominal demodulation frequency, the amplitude control circuit (4) controlling the controllable amplifier (1) in dependence upon its output signal and a signal dependent on the frequency of the output signal of a voltage-controlled oscillator (14) in the phase-locked loop in such a way that the output signals of the controllable amplifier (1) have a nominal amplitude.

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Neu Wulmstorf, Germany

Burkhard Heinke