| 摘要 |
An infrared communication system transfers secure communication signals between a source unit and a destination unit, while having low power comsumption in a wireless remote unit. The system comprises an audio processor (203), a scrambler (205), a pulse position modulator (210), a timing block (235), a transmission power controller and infrared emitters (225). The system also includes infrared receivers (250), an automatic level controller (265), a pulse position demodulator (285), a descrambler (290), an audio processor (295), a signal-to-noise ratio estimator (270), a transmission (275) power controller, and a timing block. The method comprises receiving an audio signal, processing the audio signal, adding power control signals, scrambling the signal, adding mode pulses, adjusting the transmission power, if necessary, and driving transmission emitters. The method also includes receiving the transmit pulses and performing a series of operations on the received pulses. One operation involves estimating the signal quality and accordingly acting. Another operation involves extracting power requirement command. A third operation involves extracting the signaling pulses and acting upon those commands. A fourth operationg involves extracting the audio pulses, demodulating and descrambling the audio pulses and processing the resulting analog signal to produce the communicated audio signal. The system and method simultaneously transmits from the source unit audio, power, and multiframe synchronization information through a single pulse signal that is relatively secure. The pulse signal is received and is descrambled and processed at the destination unit. The system and method is designed so that the wireless remote unit operates at the lowest power comsumption level. |
