Chroma Shaping Filter - Analog Devices ADV7850 Hardware Manual

Function
sdp_shape_std_filt_sel[
2:0]
000
001 
010
011
100
101
110
111

6.9 CHROMA SHAPING FILTER

The chroma shaping filter block can be programmed to perform a variety of low pass responses. It is used to selectively reduce the
bandwidth of the chroma signal for scaling or compression.
The ADV7850 contains 20 different C shaping filters that are available for selection using a 5-bit selection value. Three selection registers
are provided so that different C shaping filters can be selected for high quality inputs, low quality inputs, and SECAM inputs.
The metrics for the quality determination of the input signal are selected by sdp_hqi_req_std. If this bit is set then HSync PLL speed, time
base stability, and frame, field, block, or line count non standard detection are all used to determine if the input signal is high quality. If
this bit is cleared then only the HSync PLL speed is used to determine the quality.
A filter selection algorithm is used to choose the appropriate filter, depending on the input signal format, type, quality, and user settings.
Figure 26 provides a flow diagram showing the selection process.
Rev. A May 2012
Description
No filtering
0.25 sec
0.55 sec
0.81 sec
1.10 sec
1.36 sec
1.63 sec
2.00 sec
103
ADV7850