| 摘要 |
A device for controlling the rotational speed of a motor 17 (e.g. for a record turntable or a tape recorder) comprises an instruction input device 10, 10a for supplying rotation instruction signals to a microcomputer 11 which supplies rotation control signals to means 13 for controlling rotation of the motor 17. The microcomputer 11 comprises a program logic device which receives the instruction signals from the input device 10, 10a, and a timer controlled by the logic device. The logic device repeatedly starts the timer and, upon completion of each counting operation of the timer, produces a pulse with a variable delay relative to the completion of counting. The pulses are compared with tachometer pulses from the motor in a phase locked loop 13 controlling the motor. <IMAGE> |
