Optical signal transmission system - uses VCO providing modulated carrier fed to PLL at reception side

摘要

The signal transmission system has an electro-optical transducer at the transmission side and an opto-electrical transducer at the reception side. A carrier signal modulated with the information signal is provided at the transmission side via a voltage-controlled oscillator, the reception circuit having a phase-locked loop, contg. a phase detector, a regulating amplifier, a low-pass filter and a voltage-controlled oscillator. The output signal from the optical transmitter is fed to the latter phase detector, with the voltage-controlled oscillators on both sides exhibiting identical voltage/frequency characteristics. USE/ADVANTAGE - Good signal/noise ratio, with low signal attenuation or distortion. Optical telecommunications. Transmitting audio information for loudspeakers in motor vehicle separate from radio receiver.