IMAGE SIGNAL AVERAGE PICTURE LEVEL DETECTING APPARATUS

摘要

The present invention relates to apparatus for detecting the average picture level of an input image brilliance signal. The output of a first current mirroring circuit used as the load on a differential amplifying circuit, is fed into a smoothing circuit by a second current mirroring circuit. As a result the direct current voltage of the output and the detection voltage amplitude can be set optionally without causing an offset voltage in the output average picture level voltage, the current flowing through the second current mirroring circuit being zero when APL = 0%.