Automatic recording bias current setting apparatus
US4553179A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1982 |
| Grant date | Nov 12, 1985 |
| Priority date | — |
| Expiry date | Oct 13, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/03
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An automatic recording bias current setting apparatus comprises a bias current generating circuit for generating a bias current with varied level of the bias current, a testing signal generating circuit for generating two kinds of testing signals having different mid and high frequencies of an audio signal, by independently varying the levels of the testing signals, a recording and reproducing circuit for recording the two kinds of testing signals with the bias current onto a magnetic recording medium and reproducing the same, and a bias current detecting circuit for detecting the level of a bias current. The recording and reproducing circuit repeats an operation in which the two kinds of testing signals are recorded onto the magnetic recording medium and then reproduced with independently varied levels of the two kinds of testing signals under the same bias current obtained from the bias current generating circuit, for each of the different varied bias currents. The bias current detecting circuit detects respective reproduced output levels of the two kinds of testing signals with respect to the different bias currents, to detect a bias current level at a point where a difference b…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.