Abstract: Synchronizing apparatus is disclosed in accordance with the teachings of the present invention wherein the operation of a first device is regulated in accordance with the operation of a second device. The phase relationship between signals representing the operation of the first and second devices, respectively, is determined by comparison means which produces a pulse width modulated signal indicative of said phase relationship. Control signal generating means responds to the pulse width modulated signal to generate an analog signal having an amplitude established by said phase relationship. Feedback means, including variable frequency generating means, is controlled by the analog signal to modify the operation of the first device whereby said first device is urged into a synchronous relationship with said second device and the signals representative of the operation of said first and second devices admit of a desired phase relationship.