Opamp based broad band phase shifter for use in detecting flaws in the media of disks for use in disk drives
US5637999A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 19, 1994 |
| Grant date | Jun 10, 1997 |
| Priority date | — |
| Expiry date | May 19, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B33/10
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electronic system for detecting flaws in the magnetic media of raw disks prior to assembly into disk drives which works in conjunction with an electro-mechanical apparatus that performs the functions of spinning the disk, impressing a sinusoidal signal onto the media of the spinning disk and subsequently reading back the signal from the spinning disk. The signal read from the disk is supplied as the electrical output of the electro-mechanical apparatus. The system includes a divider circuit to divide the read signal into two signal channels. An op amp based impedance matching circuit is connected to the output of the dividing circuit in each channel and matches the electrical impedance of the electro-mechanical apparatus with the impedance of the remainder of the electronic detection system. It passes the two signals through substantially unaltered. A two stage op amp based phase shifter circuit is connected to each of the impedance matching circuits and generates two output signals having substantially the same amplitude as the two input signals, but a phase difference with respect to each other of substantially 90.degree. over a frequency range of approximately 3 to 22 megaher…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.