Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1990-08-01
1992-03-31
Coles, Sr., Edward L.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358461, 358464, 358475, H04N 140
Patent
active
051012812
ABSTRACT:
An automatic gain control circuit in which a first image signal from an image reading apparatus is amplified by a variable gain amplifier with a gain being automatically adjusted. The automatic gain control circuit comprises a gain adjusting part for automatically adjusting the gain of the variable gain amplifier with a white signal of a white reference part of the first image signal to supply a second image signal from the variable gain amplifier, and a pseudo white signal inputting part for inputting a pseudo white signal to the gain adjusting part before the image reading apparatus starts an image reading, the pseudo white signal being at a predetermined level approximately equal to that of the white signal of the first image signal, the first image signal being switched by the pseudo white signal inputting part with the pseudo white signal only at timings in synchronism with the inputting of the pseudo white signal to the gain adjusting part.
REFERENCES:
patent: 4133008 (1979-01-01), Tisue
patent: 4408231 (1983-10-01), Bushaw et al.
patent: 4523229 (1988-06-01), Kanmoto
patent: 4723174 (1988-02-01), Mishikawa et al.
Coles Sr. Edward L.
Ricoh & Company, Ltd.
LandOfFree
Automatic gain control circuit of image reading apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic gain control circuit of image reading apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic gain control circuit of image reading apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2263386