公开(公告)号：JPH1069741A

公开(公告)日：1998-03-10

申请号：JP16391797

申请日：1997-06-20

Applicant: SGS THOMSON MICROELECTRONICS

Inventor： BRUCCOLERI MERLCHIORRE ,  DEMICHELI MARCO ,  DEMICHELI DAVIDE ,  PATTI GIUSEPPE

IPC: G11B5/55 ,  G11B5/596 ,  G11B21/10

Abstract: PROBLEM TO BE SOLVED: To obtain a servo demodulator having high immunity against noises by temporarily holding the amplitude in detecting each peak amplitude, successively detecting a plurality of signal peaks and discharging a first capacitor whenever the weighted average is held with a second capacity. SOLUTION: A signal existing between input terminals IN+, IN- is applied to a differential comparator 6 and a peak detector 5. The signal CP is made valid when the comparator 6 is higher than a first prescribed value and the signal CN is made valid when the same is lower than a second prescribed value. The output 15 of a differential amplifier 11 is fed to switches 14, 8, and each switch is closed with the command generated with a control logic 7. The logic 7 is started with a SAMPLE signal, a reset pulse DISC is generated during the period when the signal CP is valid, a signal AVE is made to be valid when the signal CP becomes valid first, thereafter the signal AVE is made to be valid whenever the signal CN becomes valid after the signal CP became valid twice.