Grass Valley 1200 Installation - Manual (Page 83)

3-9
System Overview
Internal Accuracy
The outputs of the Model 1200 system are 10 bit precision. In order to
provide this precision, internal processes for arithmetic operations
significantly exceed 10 bits.
When the video enters the Model 1200, it is split into luminance and
chrominance, each running at 13.5 MHz. The luminance is carried down
one bus at the full 13.5 MHz. The Chrominance is carried in alternating
bytes (R-Y, B-Y, R-Y) with each of the chrominance alternating bytes
carried at a 6.75 MHz rate. The key and depth information is carried in the
same way. The key is carried at full rate; the depth information, which is 20
bits wide, alternates between the MSB and the LSB.
On the Chroma Keyer Submodule, the chrominance signal is split. The
clock rate is then upsampled to its full 13.5 MHz rate on each bus. This is
done by creating new bytes between each of the existing bytes by averaging
between the last byte and the next byte.
16 X 9
The Model 1200 can handle 16 X 9 video. The digital video 16 X 9 signal is
handled the same as 4 X 3 video. For 16 X 9, the Model 1200 must have the
setup reflect that input. The system can not handle 4 X 3 and 16 X 9 video
at the same time. When the setup is changed, it changes the counters and
the clock frequency on the Sync Pulse Module. The clock frequencies listed
in this manual are for standard 4 X 3 digital video.