Circuit for controlling the speeds of two capstans
US4471272A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 1, 1981 |
| Grant date | Sep 11, 1984 |
| Priority date | — |
| Expiry date | Oct 1, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B15/54
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The speeds of two capstans of a dual capstan type tape recorder are individually controlled by respectively associated first and second phase locked loops. Each phase locked loop includes a speed detector for generating pulses at a frequency corresponding to the rotational speed of the associated capstan, a phase detector receptive of the pulses and a motor for driving the associated capstan in response to the output of the phase detector. A reference frequency oscillator supplies a constant frequency signal to a first frequency divider and to a second, programmable frequency divider which are respectively associated with the first and second phase locked loops. The first and second frequency dividers feed their outputs to the phase detectors of the first and second phase locked loops, respectively, to allow phase comparison with the received pulse to control the associated motors. The programmable frequency divider is controlled by a preset input to vary its frequency division ratio so that the speed of the capstan on the supply reel side is driven at a speed slight lower than the speed of the other capstan to maintain the recording tape between them under taut condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.