Special Features

MULTIPLEXED VIDEO SIGNAL INPUT

The LM2457 accepts the multiplexed video signal from the

LM1253 which contains the video signal and DC clamp level.

This multiplexed signal is shown in

Figure 3. It was designed

to simplify the interface between the pre-amp and CRT

Driver. Slightly over 1V of dynamic range is provided for the

video and OSD portions of the waveform. The clamp signal

control voltage range is approximately 0.9V. The typical

numbers for the black and white levels shown correspond to

a nominal swing of 40V

LM2457.

DS101379-3

FIGURE 3. National LM1253 Multiplexed Video Signal

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