| 摘要 |
PURPOSE:To eliminate the use of a D/A converter and to reduce the distortion factor, by producing a trigger code for address code with a synchronizing signal and at the same time using the trigger signal to control an analog switch and to produce a desired address code. CONSTITUTION:A sine wave of 10Hz, for example, is obtained by a low frequency oscillator 1 and then sent to a waveform shaping circuit 2 and an analog switch 4. This sine wave is converted by the circuit into a perfect rectangular wave with a zero cross or into a rise or fall pulse of the zero cross and then sent to a microcomputer 3 in the form of a syncyronizing signal. The discrimination is carried out by the synchronizing signal between ''1'' and ''0'' corresponding to address codes at the inside of the computer 3. The switch 4 is controlled by the output of the computer 3. In such a way, the sine wave component corresponding to ''1'' of the address code is produced by transmitting a sine wave produced by a low frequency oscillator of a small distortion factor by means of a microcomputer. Therefore the distortion factor can be reduced for the sine wave component. |
