DEVICE FOR ENCRYPTING IMAGE SIGNAL

摘要

PURPOSE: A device for encrypting an image signal is provided to use a data signal as a reference of a signal by removing a synchronous signal and to improve quality of an image. CONSTITUTION: An image signal encrypting device comprises an AGC(Automatic Gain Control) unit(1) equalizing an image signal; S/H(Sample and Hold) unit(2) maintaining direct current voltage level to stabilize output; a first amplifying unit(3) amplifying the output of the S/H unit; first and second off set control unit(6,7) outputting regular direct current voltage level to apply specific direct current value into the image signal; a first mux unit(4) mixing outputs between the first amplifying unit and the first off set control unit; a second mux unit(5) outputting the image signal by adding a data signal while removing a synchronous signal; a second amplifying unit(8) compensating loss of the AGC; a synchronous signal separating unit(9) removing the synchronous signal from the image signal; a micom unit(11) controlling a display unit(12); and a logic circuit unit(10) controlling the mux units.