Write data transition detector
US4622599A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 1984 |
| Grant date | Nov 11, 1986 |
| Priority date | — |
| Expiry date | Nov 19, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10009
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A write data transition detector is provided connected across a thin film write head and write current generator and is responsive to the fractional voltage drops across the head resulting from the fractional amperage currents passed by the write generator through the head. Circuits in the detector adjust the gain of the voltage difference across the head, remove voltage spikes induced by changes in current across the head and time the period between consecutive current reversals of sufficient magnitude. The timing is controlled by means of a hysteresis circuit which switches from an existing state to an alternate state only when there is a satisfactorily large reversal of current across the write head. A timing circuit connected with the hysteresis circuit capacitively times the length of the period the hysteresis circuit remains in its existing state and outputs a fault indication current when this period exceeds the maximum period between transitions allowed by the encoding scheme employed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.