Read channel with programmable bandwidth control
US6473253B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1999 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Apr 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45648
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A feedback system includes an emitter-follower as a gain stage in the forward path. The emitter-follower has a very wide band width and does not, by itself, effectively narrow the bandwidth of an information channel in which it is used. Emitter-followers are frequently used as buffers in many gain systems so using an emitter-follower which is already present effectively reduces die area for the feedback system. In an embodiment, the feedback system includes a differentiator with a programmable zero in the feedback path. The zero in the feedback path creates a pole in the forward path and the programmed location of the zero influences the pole and controls the bandwidth of the forward path. The emitter-follower also buffers the differentiator so that it does not effect the operation of any prior gain stages in which the feedback system is used. A switch in the feedback path enables the differentiator to be turned off or switched out of the loop so that the forward path is not effected when bandwidth reduction is not required. With appropriate switching, the same differentiator is used to create a zero in the forward path as well as pole in the forward path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.