| 摘要 |
Servo circuit for electronically controlling the operation of an electric motor (100). The rotational frequency of the motor is converted into a varying frequency waveform by a tachometer (115), (120). The tachometer output is applied to a conversion circuit which includes a peak detector (125) that converts the output waveform of the tachometer (115), (120) into a square-wave signal. The square-wave signal is, in turn, connected to one input of an exclusive-OR gate (150). The peak detector square-wave signal is also applied to a shift register (140) which, after a time delay, applies the same signal to another input of the exclusive-OR gate (150). With these connections, the exclusive-OR gate (150) produces a square-wave output whose duty cycle is proportional to the speed of the DC motor. This output can then be either amplified and applied directly to the electric motor (100) to drive it, or integrated and applied to an amplifier (180) to drive the motor (100) in accordance with standard servo techniques. |
