Digital servo system for controlling rotational speed of rotary body
US4994723A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 14, 1989 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Dec 14, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P23/22
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A microcomputer 1 servo controls a rotational speed of a capstan motor 10 in a VTR in a digital manner. A value of a timer counter 6 is stored in an ICR 7 at a timing of each edge of FG signal pulses generated as the capstan motor rotates. Thereafter, in the microcomputer 1, a FG interrupt processing is carried out corresponding to the value of ICR 7. More specifically, the microcomputer 1 alternately measures a first period from a rise of one pulse of the FG signal to a rise of a subsequent pulse thereof and a second period from a fall of one pulse to a fall of a subsequent pulse to determine an amplitude of a speed error signal based on these periods. Therefore, a sampling frequency for the digital servo control can be double that of a prior art.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.