Gain regulator for TV signal amplifier - compares signal sample pulse and reference pulse lengths to produce gain control signal

摘要

The gain regulator, for a television signal amplifier, prevents interference from causing variation in amplitude by generating a sample pulse by comparing the level of the demodulated video signal with a sample level. The length of the sample pulse is determined by the length of the video signal component that lies in the region of the sync. pulse and exceeds the sample level. At the appearance of each sample pulse a reference pulse equal in length to the sync. pulse is generated. a control signal is obtained by comparing the lengths of the sample pulse and the reference pulse whenever the sample pulse is longer than the reference pulse. The control signal is then fed to a control element preceding the amplifier.