we are using AD9970, output saturation voltage of sensor is 900mV, but with light intensity's increase, amplitude will increase,too. amplitude is about 1~2V, this is application premise; issue appear in supersaturated status, supersaturated is up to certain amount,output of image is 12bit,4095, at this time, set CDS gain from 0dB to 3dB, but gray level of video will decrease from 4095 to 4075, and gray level is fixed.
if go on increasing light intensity without CDS gain change,gray level of video will decrease, light intensity increase more,reversal gray level is bigger,and it is one fixed value.
question: CDS gain function here? these circuit operate principle?
in addition, if unable CLPOB function,video don't reversal in supersaturated status, test AD9970 input signal,average amplitude of black level is 500mV, amplitude of effective pixels is about 1.5V, it may be saturated according analog signal's calibration. what is reason of above phenomenon, operation principle?
thanks!