Scaler Block - Philips DPTV400 Series Training Manual

FIGURE 24 - SCALER BLOCK DIAGRAM
Scaler Block (Figure 24)
There are two input ports to the Scaler IC, A and B. The two 24 bit video inputs are fed to a
Multiplexer. The Multiplexer selects the picture information for the main picture and the Picture in
Picture. Separate Horizontal and Vertical Sync for the A-Port is fed to the IC on Pins 156 and 157.
Sync for the B-Port is fed to the IC on Pins 9 and 10. In the case of Sync on Green or Sync on Y, the
Green or Y signal is fed to the IC on Pin 207. The Sync is separated inside the IC. The frequency of
the Horizontal and Vertical Sync is used for signal processing timing and Format detection.
The selected picture data is fed to the Format circuits to resize the picture. The CSC (Color Space
Conversion circuit) changes the data to a YCbCr format if the input signal is in the RGB format.
The Image Processor enhances and Formats the picture. IC 7600 stores the picture data as it is
being processed by the Image Processor.
The Scaler converts the output to a1080i format. The signal is fed to three D/A converters. The IC
then outputs an analog Y Pb Pr output. Horizontal and Vertical sync is output on Pins 49 and 50.
The Vertical is 60 Hz while the Horizontal is 33.75 kHz.
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