SAA7113H
Philips Semiconductors
9-bit video input processor
8.4 Luminance processing
The 9-bit luminance signal, a digital CVBS format or a luminance format (S-VHS and HI8),
is fed through a switchable prefilter. High frequency components are emphasized to
compensate for loss. The following chrominance trap filter (f0 = 4.43 MHz or 3.58 MHz
center frequency set according to the selected color standard) eliminates most of the color
carrier signal. It should be bypassed via I2C-bus bit BYPS (subaddress 09h, bit 7) for
S-video (S-VHS and HI8) signals.
The high frequency components of the luminance signal can be peaked (control for
sharpness improvement via I2C-bus subaddress 09h; see Table 37) in two band-pass
filters with selectable transfer characteristic. This signal is then added to the original
(unpeaked) signal. For the resulting frequency characteristics see Figure 11 to Figure 18.
A switchable amplifier achieves common DC amplification, because the DC gains are
different in both chrominance trap modes. The improved luminance signal is fed to the
BCS control located in the chrominance processing block (see Figure 19).
mgd139
18
V
Y
(dB)
(1)
(2)
(4)
(3)
6
−6
−18
−30
(1)
(2)
(4)
(3)
0
2
4
6
8
f
(MHz)
Y
(1) 43h.
(2) 53h.
(3) 63h.
(4) 73h.
Fig 11. Luminance control subaddress 09h, 4.43 MHz trap/CVBS mode, prefilter on and
different aperture band-pass center frequencies
9397 750 14232
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Product data sheet
Rev. 02 — 9 May 2005
15 of 75
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