| 摘要 |
PURPOSE:To avoid the error in modulated pulse width, by always keeping constant the residual voltage of a capacitor of the pulse width modulation circuit before analog voltage input, through a constant voltage from the constant voltage supply. CONSTITUTION:The system provides the constant voltage source E0 outputting a given voltage, constant voltage electronic switch S0 inputting the constant voltage of the constant voltage source to the pulse width modulation circuit 4, and electronic switch selection control circuit 7 in which the change-over is made to the constant voltage electronic switch S0 from either one of the electronic switches S1-S3 of a plurality. Further, a given voltage of the constant voltage source E0 is input at the middle where the analog voltages e1-e3 of a plurality are input to the pulse width modulation circuit 4, allowing to keep constant for the residual voltage of the capacitor of the pulse width modulation circuit 4 before the input of analog voltage inputs e1-e3. Thus, modulated pulse width can have no error. |
