| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a signal processing circuit that converts a received analog signal into a digital signal and can automatically adjust the sensitivity. SOLUTION: The signal processing circuit uses a controlled variable required to make an input signal voltage V in matching with a reference voltage Vref for a digital conversion value of the input signal voltage. The signal processing circuit stores a maximum value of the luminance of an input image to a solid- state image pickup element 1 denoted by the digital signal, converts it into an analog signal and feeds it back to an input of a comparator 60 as the Vref. Even when the luminance of the input image is remarkably increased and gets higher, the controlled variable is not saturated and when the luminance is not increased, and the analog signal with a small luminance can be analog/digital- converted.</p> |
