msm7661b Oki Semiconductor, msm7661b Datasheet - Page 11

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

¡ Semiconductor
BLOCK DESCRIPTION
1.
The prologue block performs Y/C separation by inputting data.
Data can be input either at ordinary pixel frequency (ITU-R : 13.5 MHz) or at double pixel
frequency (ITU-R: 27 MHz).
When the double pixel frequency is used, data is processed after changing to the ordinary pixel
frequency via a decimeter circuit.
By changing the register setting, the decimeter circuit can be bypassed irrespective of whether
data is input at ordinary pixel frequency or at double pixel frequency.
The prologue block performs Y/C separation using a 2-dimensional adaptive comb filter when
composite signals (CVBS) are input.
The following operation modes can be changed via the I
The default is a state that is selected when reset.
1) Video input mode select
2) Video input mode select
3) Operation mode select
4) Decimeter circuit pass/bypass select
5) Y/C separation mode select
The adaptive comb filter detects the correlation up to 3 lines between continuous lines. The Y/
C is separated by the comb filter according to the way of correlation if theses lines are correlated.
The Y/C is separated by the trap filter if these lines are not correlated (only 2 lines in the case of
PAL).
In the unadaptive comb filter, the Y/C is always separated by removing the luminance
component based on the average of preceding and following lines (when there is the correlation
between 3 lines).
Composite video input *
S video input
Auto NTSC/PAL select* (Only for ITU-R601)
Dependent on Operation mode selected
When ITU-R601 is selected, the video input mode is automatically determined by the number
of lines per field.
NTSC CCIR601
MTSC Square Pixel
NTSC 4Fsc
PAL CCIR601
PAL Square Pixel
Decimeter circuit is passed. *
Decimeter circuit is bypassed.
Adaptive comb filter is used. *
Unadaptive comb filter is used.
Trap filter is used.
Prologue Block
13.5 MHz*
12.27 MHz
14.31818 MHz
13.5 MHz
14.75 MHz
2
C-bus. The * mark indicates a default.
MSM7661B
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