PURPOSE: To obtain a testing device which can easily be applied with an AGC voltage by using a test signal obtained by inserting an automatic gain control signal in time-division mode synchronizing with a horizontal synchronizing signal.
CONSTITUTION: Test signal S1 of test signal generator 1 and AGC signal S2 of AGC operating signal generator 16 are changed over alternately by high-speed changeover circuit 18 before being applied to the antenna input terminal of receiver 3 to be tested. A signal from cathode terminal 12 of the picture tube of receiver 3 is applied to measuring device 20 through signal processing circuit 19 to test selectivity characteristics, for example, of receiver 3. A synchronizing signal from synchronizing signal generator 21 is applied to signal generator 16 and changeover unit 18 and AGC signal S2 is inserted into test signal S1 synchronizing with a horizontal synchronizing signal and also applied to the signal processing circuit. Consequently, while the AGC voltage is applied to a high-frequency amplifying circuit and video intermediate-frequency amplifying circuit, the test signal can be measured.
FUKUMOTO SEIICHI
TSUJI TOSHIHIKO
