Appendix A Scaling and I/0 Timing Register Calculations
CX25870/871
Flicker-Free Video Encoder with Ultrascale Technology
Figure A-1. Allowable Overscan Compensation Ratios for Dual Display, 640x480 Input, NTSC Output with 20 Clock
HBlank Period
Overscan Compensation Pecentage Pairs for 640x480 NTSC
22
20
18
16
14
12
10
8
8
10
12
14
16
18
20
22
Vertical Overscan Compensation Percentage
Legend:
= Pixel Clock Solution
= 8-Cycle Character Clock Solution
= 9-Cycle Character Clock Solution
NOTE(S):
Use this chart for PAL-M and PAL-60 allowable overscan ratios.
100381_026
A-4
Conexant
100381B