Patent ID: 7301678
Filing Date: 2007-11-27
Classification: H04N

Abstract:
1. An image reading device, comprising: a charge coupled device which photoelectrically converts optical information and outputs an image signal in an analog form; a programmable gain amplifier which receives an output from said charge coupled device, amplifies the output with a programmable gain, and outputs the output; an analog digital converter which receives an output from said programmable gain amplifier, analog/digital-converts the output, and outputs an image signal in a digital form; and a central processing unit which calculates a gain which makes an output from said analog digital converter match a reference value by using an output from said analog digital converter and the reference value, and setting a gain for said programmable gain amplifier, wherein said programmable gain amplifier, comprises: wherein said Central Processing Unit sets a gain by ON/OFF-controlling the first switch, the second switch, . . . , and the nth switch.