Filtering a read signal to attenuate secondary pulses caused by pole tips of a thin film magnetic read head
US5623377A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1994 |
| Grant date | Apr 22, 1997 |
| Priority date | — |
| Expiry date | Apr 4, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A filter for compensating discrete secondary pulse formations associated with a data stream of discrete main pulses produced from data read from magnetic media. The filter's impulse response comprises a center coefficient with side compensating coefficients for attenuating the secondary pulses when the input signal is convolved with the impulse response. The magnitude and delay of the compensation coefficients are programmable and are adaptively adjusted to optimize the impulse response for a given environment. In a traditional FIR embodiment, two delay lines are used to generate the two programmable delays between the center coefficient and side compensation coefficients. In the preferred embodiment, an IIR filter provides the two programmable delays using only one delay line thereby reducing the size and cost of the circuit. Also in the preferred embodiment, the data stream is interleaved into an even and odd data stream and processed in parallel by two filters in order to double the throughput. Further, the pre-cursor correcting portion of the filter can be disabled in order to avoid delaying the data stream while still canceling the post-cursor secondary pulses. The filter also…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.