| 摘要 |
PURPOSE:To secure simple increment for the control types by switching the frequencies of the carrier waves to be modulated with the pulse code via each of keyboards connected in parallel. CONSTITUTION:Keyboard 1A and 1B are connected in parallel to encoder 3. The output signals of pulse code generation circuit 4 are applied to modulation circuit 5 to modulate the carrier waves of ultrasonic frequencies. This modulated signal is then applied to light emitting circuit 16 to radiate the modulated control signals of the infrared light in the form of the remote control signals. For discrimination of the signals for two pairs of keyboards, the control unit generates the switching pulse at switching pulse generation circuit 19 when keyboard 1B of the lower part is operated. Thus, the frequencies of the carrier waves are switched. |
