AUTOMATIC CORRECTOR FOR FREQUENCY CHARACTERISTICS

摘要

PURPOSE:To always secure the steady reproduced picture by inserting the white- level signal into one horizontal scanning section in order to block the change of the frequency characteristics. CONSTITUTION:The video signal sent from input terminal 1 is applied to encoder circuit 2 and then supplied to adder circuit 3 after converted into the signal format suited to the recording and reproduction. The video signal is also applied to synchronous isolating circuit 4 for isolation of the horizontal and vertical synchronous signals, and is then applied to white-level generating circuit 5 as well as to gate pulse generating 6 to produce the white-level signal and the gate pulse signal. These two signals are supplied to gate circuit 7 to secure occurrence of the white level in the horizontal scanning section in the vertical blanking section. This white level is applied to circuit 3 to be added to the signal sent from circuit 2. This composite signal is sent to the recording circuit via FM modulator 8 to be recorded to the disk. In the case of the reproduction, the frequency characteristics is changed to give correction to the transmission properties with the control signal of the transmission properties correcting circuit and through the detection of the white level.