| 摘要 |
PURPOSE:To reduce radio noise and to reduce cost and make a circuit light in weight as compared with the addition of a filter, etc., by providing a logical circuit on the side of an inverter so that a noise mask signal may be transmitted to the side of a receiver only when inverter current is large. CONSTITUTION:When switching noise is generated, it becomes the reception noise of a radio. Therefore, a mask signal is generated by synchronizing with this timing and the signal is added to an AGC circuit 45. The generation logic of this signal is mentioned in the followings. When an accel opening becomes a certain value or more, a comparator becomes high, each gate voltage is made to pass an insulation circuit 58. When the output voltage changes, the voltage is made to pass a differential circuit 57 generating a high signal for a certain time and further, the voltage is impressed on an AND gate 51 via OR gates 54 to 56. By generating a mask signal by this signal and changing the gain of the AGC circuit 45 by an inverter circuit 50, speaker noise can be reduced. |
