Control circuit for a memory type electric shutter
US4170411A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1976 |
| Grant date | Oct 9, 1979 |
| Priority date | — |
| Expiry date | Dec 17, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B6/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the system disclosed, a feedback circuit connects the output of the last of a plurality of cascaded amplifier stages to the input of the first stage. A photoelectric transducer is connected to one of the stages. The feedback connection compresses the output signal relative to the signal at the photoelectric transducer, logarithmically. Preferably all the stages are linear and the feedback circuit is linear so that no logarithmic members are required. Preferably each of the stages is composed of an amplifier and a connection corresponding to an emitter-follower connection. A suitable system then utilizes the compression characteristic in a shutter control. This system may use a second compression circuit comparable to the first. Additional photographic information may be applied to the input of any of the stages in either compression circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.