0.700 V/1.305 V
1023
0.000 V/0.000 V
0
Figure 4–39. RGB Without Sync Insertion or Composite Video Output
The figure below shows the linear DAC I/O relationship for either of the two nominal full-scale settings.
Ramping Output With Different Full-Scale Ranges
1.305 V
0.700 V
0
255
511
767
1023
Input Digital Codes
Figure 4–40. Ramping Output With Different Full-Scale Ranges
4.8.2 SMPTE-Compatible RGB Output With Sync Signal Inserted on G (Green) Channel
In this mode, a tri-level (HDTV modes)/bi-level (SDTV modes) sync signal is inserted into the G channel. The nominal
analog output voltage range, which is from the sync tip to the peak of active video, is from 0.0 V to 1.050 V. During
the active video period, the peak-to-peak ac value (dynamic range) is 700 mV (from 350 mV to 1050 mV). The blank
levels on all three channels correspond to the bottom code 64 and are at 350 mV. Figure 4–41 and Figure 4–42
illustrate the analog video output signals, both the output from the G channel with a tri-level or a bi-level sync pulse
inserted, as well as the outputs from R and B channels. No sync signal is inserted during the sync period on R and
B channels.
Alternatively, sync can be inserted on all three channels on THS8200 by appropriately programming the sync
amplitude levels. On those channels where no sync is inserted, the blank levels are maintained at a 350-mV dc level.
4–36
TI [ TEXAS INSTRUMENTS ]
