Automatic white balance circuit of color television camera

Abstract

Abstract PURPOSE:To maintain an adjustment state even after the power source is turned off by providing a variable resistance for level control over a specific video signal and by driving this variable resistance by a level difference detection output. CONSTITUTION:Outputs G, R and B of an image pickup tube are supplied to white balance circuit 4 via preamplifiers 1, 2 and 3. In white balance circuit 4, outputs R and B are supplied to amplifiers 11 and 12 via variable resistors 21 and 22. Variable resistors 21 and 22 are driven by motors 23 and 24 and their driving signals are level differences between outputs of amplifiers 11 and 12, and that of amplifier 8 outputting output G. Consequently, the white balance state is held by variable resistors 21 and 22 even after the power source is turned off.

Inventors

• 👤 Hideo Onodera

Bibliographic Details