Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of the amplifier
Patent
1979-04-19
1981-11-03
Canney, Vincent P.
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of the amplifier
360 39, G11B 502, G11B 509
Patent
active
042988985
ABSTRACT:
A magnetic head reads data from reference zones on tracks at differing ra of a magnetic memory disc rotating at constant angular velocity. Each track includes at least one reference zone, each of which includes a plurality of initial cells. Each cell has magnetic flux variations, which when read by the head result in a first waveform that includes undulations enabling the head to be properly servo controlled to a position over the center of the track and a further undulation that is distinguishable from the head positioning undulations. The initial cells are followed by plural binary bit representing data cells each having magnetic flux variations which when read by the head result in a second waveform including a data representing undulation that is generally the same amplitude as the further undulations. The undulations are susceptible to having varying amplitudes as the head is positioned at different positions of the disc. The peak amplitude of the further undulations, for one reference zone, is detected. In response to the detected peak amplitude of the further undulations a threshold for the data representing undulations is set and maintained while the second waveforms for the cells of the reference zone are read by the head. The set threshold and amplitude of the second waveforms are compared to enable the binary value of each data cell to be determined. A feedback look controls the gain of an amplifier that derives the signal to be detected for peak amplitude, except immediately after a change is ordered for a transition to read data from heads on opposite faces of the disc, at which time the gain is maximized.
REFERENCES:
patent: 3206689 (1965-09-01), Santena
patent: 3593333 (1971-07-01), Oswald
patent: 3593334 (1971-07-01), Bickel
patent: 3653062 (1972-03-01), Hollstein, Jr.
patent: 3660821 (1972-05-01), Weber et al.
patent: 3662365 (1972-05-01), Rodriguez
patent: 3691543 (1972-09-01), Mueller
patent: 3840756 (1974-10-01), Jones
patent: 3879674 (1975-04-01), Dragon
patent: 4091380 (1978-05-01), Yu
Canney Vincent P.
Compagnie Internationale pour l'Informatique Cii Honeywell Bull
LandOfFree
Method of and apparatus for reading data from reference zones of does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of and apparatus for reading data from reference zones of, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of and apparatus for reading data from reference zones of will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1067383