| 摘要 |
PURPOSE:To select a channel of transmission optionally by converting sound signals of plural channels from analog to digital, and driving a light emitting element by a serial digital signal generated within one frame by time-division multiplexing. CONSTITUTION:The sound signals of plural channels CH are inputted to A-D converters 3a-3p through variable LPFs 2a-2p and converted there into digital signals, which are inputted to a multiplexer (MPX)6. The MPX6 multiplexes the input signals to the numbers of CHs corresponding to a mode by a control signal from a switching circuit 4 selected with a mode selection switch 5. Further, a clock from a clock signal generator 8 is frequency-divided to generate the serial signal consisting of a synchronizing bit, specific-bit digital signals of plural CHs or signals obtained by dividing 1/nCH bits of plural CHs by (n), and a control and a parity signal by a serial register 16. Then, the light emitting diode 20 is driven by the signal obtained by converting 18 the serial signal into the biphase signal, which is appropriated for an NRZ signal. |
