Amplifier device with digitally controllable gain and optical disc read apparatus incorporating such a device
US6184752A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 6, 1999 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | Oct 6, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0941
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The device has reference current sources (T.sub.71, T.sub.72, T.sub.7M) which are arranged in such a way that the sum of the currents flowing through each of the said sources is equal to the input current (I.sub.IN, I'.sub.IN) and output current sources (T.sub.81, T.sub.82, T.sub.8N), in each of which the current flowing through the reference sources is duplicated and which are arranged in such a way that the sum of the currents flowing through the output sources is equal to the output current (I.sub.OUT, I'.sub.OUT). The number of reference sources (T.sub.71, T.sub.72, T.sub.7M) and output sources (T.sub.81, T.sub.82, T.sub.8N) which are connected is controlled by the digital signal (200) and determines the gain of the device. Application to the circuit for processing the signals output by a read head of an optical disc reader apparatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.