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I. VIDEO AMP. CIRCUIT
I-1. VIDEO PRE. AMP.
The video pre-amp IC is U301(KA2143B). The input signal is 0.7Vpp, then pre-amp IC U301 amplify
the video signal to 4~5Vpp. The WHITE BALANCE and CONTRAST shall be adjusted by
adjustment the bias voltage of U301. Fig.4 is the block diagram.
I-2. VIDEO AMPLIFIER
The video amplifier is U303(LM2439), it amplify video signal to about 40Vpp. Video output signal
add to cathode by AC coupling. The DC bias is controlled by the output pwm of IC U302.
Fig.5 is the block diagram
I-3. BLOCK DIAGRAM
KA2143B
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