THS8200 Datasheet, PDF (28/97 Pages) Texas Instruments – ALL FORMAT OVERSAMPLED COMPONENT VIDEO/PC GRAPHICS D/A SYSTEM WITH THREE 11-BIT DACS,CGMS DATA INSERTION

11_ÎÎÎ+_{–1δδ ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ}
–6 dB
–40 dB
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
2.75 3.375 4.0
Frequency (MHz)
NOTE: δ = 0.05 dB
Figure 4–11. Cb and Cr Filter Requirements Based on ITU-R.BT601
Figure 4–12 through Figure 4–14 illustrate the frequency and phase responses of the interpolating filters. The actual
response using the finite-word length coefficients present in THS8200 is shown. The same filter characteristic is used
for SDTV/HDTV modes and for both 4:2:2 to 4:4:4 interpolation (2 filters, one on each of Cb and Cr channels, switched
in when a 4:2:2 input mode is selected on DMAN to interpolate chrominance from 1/2 to 1× pixel clock rate) as well
as for 2× video oversampling (3 filters, one on each DAC channel, switched in when 2× interpolation is activated).
MAGNITUDE
vs
FREQUENCY
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
f – Frequency – Rad
Figure 4–12. IFIR Frequency Response
MAGNITUDE
vs
FREQUENCY
0.0110
0.0089
0.0068
0.0047
0.0026
05
–0.0024
–0.0043
–0.0062
–0.0081
–0.010
0.00 0.25 0.50 0.75 1.00 1.25 1.50
f – Frequency – Rad
Figure 4–13. IFIR Pass-Band Frequency Response
4–13