Tape player preamplifier circuit responsive to tape speed
US4004293A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 31, 1975 |
| Grant date | Jan 18, 1977 |
| Priority date | — |
| Expiry date | Oct 31, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B23/0007
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A preamplifier circuit for a tape player includes a voltage-follower transistor which is operable when turned on to establish the output bias voltage of the preamplifier circuit at substantially a reference voltage. In turn, a voltage divider network develops the reference voltage coincident with energization of the tape transport mechanism. Due to the inertia of the tape transport mechanism, the speed of the tape remains below that necessary for undistorted operation during a start-up time period immediately following energization of the tape transport mechanism. An RC network is responsive to development of the reference voltage to provide a time delay such that the voltage-follower transistor is prevented from turning on until after expiration of the start-up time period. Thus, the output bias voltage of the preamplifier circuit is not established until the tape speed is sufficient to permit undistorted operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.