Features
provides a multiplexed video signal (VideoPlex) interface to enable the DC clamp levels at
the cathode to be varied in order to set up the CRT bias and to allow individual adjustment
for brightness.
The Analog OSD has a selectable palette allowing a wide selection of colors. The preset
level of the OSD can be controlled by I2C to suit different CRT displays. The OSD signal is
internally mixed with the video signal, before the gain section, and thus gives excellent
white tracking of the OSD with the white color point setting of the video.
The Brightness settings are also mixed into the video signal before the gain matching
controls and consequently give excellent white color point tracking with variations in the
Brightness control. An active horizontal blanking signal is added to the video at the output,
giving excellent smear performance, and preventing video content dependent DC bias
offsets as a result of high frequency over shoot.
The OSD horizontal sync and blanking signal is derived from a positive going flyback pulse.
The digital section provides easy interfacing of this signal with the deflection circuits.
The vertical blanking signal is taken from the vertical sync signal, and the blanking duration
is programmable. This system is highly integrated and requires a minimal number of
external components.
Black level clamping of the signal is carried out directly on the AC coupled input signal into
the high impedance preamplifier input, thus eliminating the need for additional black level
clamp capacitors.
The outputs are referenced to a DC level produced by the LM1253A Pre-amp, and so are
guaranteed to provide stable DC operating levels within the system without the need for
additional external feedback components.
The IC is packaged in an industry standard wide body 28-lead DIL molded plastic package.
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190 two-color ROM based Character Fonts
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64 four-color ROM based Character Fonts
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Supports a programmable page size with up to 512 characters and line definition
codes
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Support for 2 Display Windows (size of each window is configurable)
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Programmable start position for each Display Window