Television camera

Abstract

Abstract PURPOSE: To secure the black balance through automatic acquisition of the light shielding state by giving the closed state for the diaphragm of the automatic stop- down device according to the operation of the operation switch which turns the black balance adjusting circuit into the active state. CONSTITUTION: Change-over switch 14 of the adjusting circuit is turned toward fixed contact 14b to secure black balance BB, and thus output terminal 12 of the auto-iris signal is clamped nearly to the earth potential via diode 13. As a result, the servo circuit of the auto-iris device receives supply of about OV, so the iris of the TV camera features the closed state to cut off the incident rays to the camera. At the same time, memroy circuit 6 and 7 feature the active state each with the action control terminal K turned to the earth potential. As a result, the active state is secured to both the control loop comprising AGC circuit 1, operational amplifier 4 and circuit 6 and the control loop of AGC circuit 2, operational amplifier 5 and circuit 7 respectively. Then output R'=G=B' is obtained to carry out the adjustment of BB. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Hisashi Ushijima
• 👤 Teiji Iwasaki

Bibliographic Details