
TFP6422, TFP6424
PanelBus
DIGITAL TRANSMITTER/VIDEO ENCODER COMBO
SLDS118 – MARCH 2000
26
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Figure 5. Luma Filter Frequency Response
f – Frequency – MHz
–40.00
–35.00
–30.00
–25.00
–20.00
–15.00
–10.00
–5.00
0.00
5.00
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
GAIN
vs
FREQUENCY
NTSC_SQP
PAL_SQP
PAL_CCIR
NTSC_CCIR
Gain
–
dB
Figure 6. Luma Interpolation Filter Frequency
Response
f – Frequency – MHz
–3.00
–2.50
–2.00
–1.50
–1.00
–0.50
0.00
0.50
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
GAIN
vs
FREQUENCY
NTSC_SQP
PAL_SQP
NTSC_CCIR
PAL_CCIR
Gain
–
dB
cross color reduction filter
An optional cross color reduction filter can be applied to the luminance signal before the luminance signal
combines with the chrominance signal to form the composite signal. The cross color reduction filter reduces the
interference between luminance and chrominance in the composite signal. This filter does not apply to S-video.
chrominance encoding
A pair of programmable gains adjusts the time-multiplexed U/V signal. The gain for U and the gain for V are
independently controlled by GAIN_U and GAIN_V register bits respectively at subaddresses 5B, 5C, 5D and
5E. The gain-adjusted signal then passes through a chrominance lowpass filter to limit the bandwidth of the U/V
signal. See Figure 7 for the filter frequency response. The chrominance lowpass filter can be bypassed by
setting CBW bit of M_CONTROL register at subaddress 61 to 0. This setting enlarges the bandwidth on U/V
for S-video output.
The lowpass U/V signal is then subjected to a 1-to-4 interpolation through a two-stage interpolation filter. The
data rate for both U and V is now at 2X-pixel rate.
The U and V signals are then quadrature-modulated by the internally generated subcarrier signal to form the
chrominance (C) signal. The subcarrier reference signal color burst is inserted right before the active video.
PRODUCT
PREVIEW