公开(公告)号：FR2756688A1

公开(公告)日：1998-06-05

申请号：FR9715305

申请日：1997-12-04

Applicant: NEC CORP

Inventor： YOSHIDA MASANORI ,  YONEYAMA KENICHI ,  TAURA TOHRU

IPC: H03L7/08 ,  H04B10/00 ,  H04B10/07 ,  H04B10/508 ,  H04B10/54 ,  H04B10/588 ,  H04L7/033 ,  H04B10/152

Abstract: The circuit includes a reference oscillator (103) for generating a reference signal which is offset by a multiple of the clock frequency. There is also a voltage controlled oscillator (110) for generating a clock signal. An optical system creates a difference component for the frequency difference between the operational frequency and the reference. A detector produces an electrical signal representing the difference frequency. A multiplier (107) creates a component for the frequency difference between the output signal of the reference oscillator, and the output of the voltage controlled oscillator. A phase detector compares the phase of the optical signal detector output with the multiplier output, to enable a control mechanism to supply a control voltage to the voltage controlled oscillator.