Servo circuit for capstan motor
US5126894A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 2, 1990 |
| Grant date | Jun 30, 1992 |
| Priority date | — |
| Expiry date | Jul 2, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B15/4675
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A servo circuit for a capstan motor has an element for recording a position detecting signal on a medium transported by the capstan motor, a magnetic head for reproducing the position detecting signal, a position detecting circuit for detecting a position error signal, a pulse generator for a pulse signal, a velocity detecting circuit for a velocity error signal, a phase comparator for comparing the phase of a clock signal and pulse signal and for outputting a phase error signal, a switch for selectively outputting the position error signal or the phase error signal, and a velocity control element for controlling the capstan motor by a velocity control signal. The servo circuit comprises a signal holding element connected in series to a signal supply path from the position detecting circuit to the velocity control element via the switch; a comparator circuit for outputting a detection signal when the phase error signal is within a predetermined level range; a holding control element responsive to the detection signal for controlling the signal holding element in a manner that in the case where the servo circuit is transited to a recording mode, until a transporting speed of the med…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.