Samsung S5PC110, Manual

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S5PC110_UM 7 6BTVOUT & VIDEO DAC
7-8
7.5 ANTI ALIASING FILTER (AAF MODULE)
The color TV signals are composed of luminance video, chrominance video and audio data which are modulated
by different sub-carriers. Hence, some spectral shaping to avoid the aliasing between them is required. ITU-R
BT.407 recommends that the luminance data (Y) should be band-limited within 4.2, 5.0, 5.5, or 6.0 MHz with
respect to video standards to avoid the crosstalk between audio sub-carrier and the luminance data. It also
recommends that the chrominance data (Cb and Cr) should be band-limited within 1.3 MHz to avoid the crosstalk
between chrominance sub-carrier and the luminance data. If audio multiplexing is not required, band-limiting of
luminance data (Y) may be skipped. Similarly, band-limiting of chrominance data (C) may be skipped at S-video
encoding rather than CVBS encoding.
The AAF sub-module in TVOUT provides 23-tap linear FIR filters for spectral shaping of luminance data (Y) and
chrominance data (Cb and Cr). The filter responses are fully programmable since filter coefficients themselves are
controllable. Since linear FIR filters have symmetric coefficients, 11 coefficients completely defines the filter
responses. The registers SDO_Y0, SDO_Y1… and SDO_Y11 are used to control the luminance filter response.
The register SDO_CB0, SDO_CB1… SDO_CB11, and SDO_CR0, SDO_CR1… SDO_CR11 are used to control
the chrominance Cb and Cr filter responses, respectively.
The
Table 7-1
show typical settings of filter coefficients. Note that there is no filtering on luminance (Y) data. Since
many CE devices usually do not output multiplexed audio, filtering on luminance (Y) data is not required. Filter is
not normalized and the dc gain of the filter may vary with the video scale. Refer to 3.1.5 SDO Video Scale
Configuration Register and 3.1.10 ~ 3.1.45 SDO Anti Aliasing Filter Coefficients.
Table 7-1 Filter Coefficients of Anti-aliasing Filters for Luminance Y
Register
7.5 IRE Setup/
7:3 Sync
7.5 IRE Setup/
10:4 Sync
0 IRE Setup/
7:3 Sync
0 IRE Setup/
10:4 Sync
SDO_Y0 0 0 0 0
SDO_Y1 0 0 0 0
SDO_Y2 0 0 0 0
SDO_Y3 0 0 0 0
SDO_Y4 0 0 0 0
SDO_Y5 0 0 0 0
SDO_Y6 0 0 0 0
SDO_Y7 0 0 0 0
SDO_Y8 0 0 0 0
SDO_Y9 0 0 0 0
SDO_Y10 0 0 0 0
SDO_Y11 252 25D 281 28F