Parallel transmission of vehicle mirror control signals by a single optical fiber

Describes a vehicle mirror control signal transmission system consisting of a transmitter, a single optical fiber, and a receiver terminal. The transmitter in the mirror controller to be operated by the driver controls the mirror functions, and the receiver terminal consists of a multifrequency receiver, a data processor, mirror control circuits to control an inner rearview mirror, and a pair of outside door mirrors. Multifrequency signals at 135, 235, 335, and 435 kHz are encoded to obtain 4-bit binary data that specifies the instructions to control these mirrors. The 4-bit multifrequency signal identified as 4-bit binary data is formed in accordance with the frequency division multiplexing (FDM) scheme, fed to the voltage-controlled oscillator (VCO) to obtain the square-wave frequency modulation (SWFM) signal in accordance with the SWFM scheme, and then transmitted from the transmitter to the receiver terminal through a single optical fiber. After the 4-bit binary data is reproduced from the 4-bit multifrequency signal, the mirrors are controlled by the data processor to accomplish their operating functions satisfactorily.