Digitally gain-controlled amplifying device, and camera using such a device
US5923213A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Jul 9, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An amplifying device has a decibel gain that evolves quasi-linearly as a function of the digital value of a control word C(O:M-1). The device includes: an amplifying stage with K amplifiers having mutually different decibel gains, the gain in decibels of each amplifier being a multiple of the same value G0; a switching stage with K switches; a gain-controlled amplifier having a gain which varies between 0 and G0 as a function of the value of the N least significant bits (C(O:N-1)) of the control word received at its digital input; and a decoder receiving a digital word including the (M-N) most significant bits (C(N:M-1)) of the control word. The decoder has K logic outputs controlling the K switches.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.