Shielded contacting device

摘要

A motor control system provides a low-cost method of phase-locking a motor to an input timing signal. Timer circuits 502, 506 measure the period of a timing signal and the relative phase between the timing signal and a motor rotor. A frequency command generator circuit 520 outputs a motor speed command based on the period of the timing signal and the relative phase of the timing signal compared to the motor rotor. The motor speed command controls the output of a motor driver circuit which drives the motor rotor speed synchronously with the input timing signal. The rotor speed is gradually altered to adjust the relative phase between the input timing signal and the motor rotor. This results in a small frequency-lock error being used to maintain a predetermined phase relationship between the timing signal and the motor rotor.