msm7661b Oki Semiconductor, msm7661b Datasheet - Page 12

• Manufacturer Part Number: msm7661b
• Description: Ntsc/pal Digital Video Decoder
• Manufacturer: Oki Semiconductor

¡ Semiconductor
If the comb filter is not used, the Y/C is separated by the trap filter.
The Y/C separation circuit is bypassed by S video signal input.
In adittion, the functions of this block work only when lines are valid as image information.
The processing of CVBS signals is not made during V-blanking.
2.
The luminance block removes synchronous signals from the signals containing luminance
components after Y/C separation. The signals are corrected and output as luminance signals.
The luminance signal output level gain control functions include three selectable modes such as
AGC (Auto Gain Control), MGC (manual Gain Control) + No Clamp, and MGC + Pedestal
Clamp.
In the AGC mode, the luminance level amplification is determined by comparing the depth of
SYNC with the reference value. The default is 40IRE which can be changed by the register. The
input is a sync chip clamp type.
In the MGC + No Clamp mode, the luminance signal output level is not affected by the input, and
the amplification and black level are controlled by setting the register.
In the MGC + Pedestal Clamp mode, the signal output level is clamped to the pedestal level of
the input. The signal amplification and black level are controllable from the clamped point by
setting the register.
This block can select the follwing operation modes.
1) Use of prefilter and sharp filter
2) Selection of aperture bandpass filter coefficient
3) Coring range select
4) Aperture weighting factor select
The profile of these signals can be corrected by coring and aperture correction.
5) Use of pixel position correction circuit
6) AGC loop filter time constant select
Used*
Not used
These filters are used for enhancing the edges of luminance component signals.
Middle range*
High range
off*
0*
0.25
0.75
1.5
Used*
Not used
Slow
4LBS
5LBS
7LBS
Luminance Block
Factor value 1/1024n
MSM7661B
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