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參數(shù)資料
| 型號： | SAA4960 |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | 信號分離 |
| 英文描述： | Integrated PAL comb filter |
| 中文描述： | Y/C SEPARATOR IC, PDIP28 |
| 封裝： | 0.600 INCH, PLASTIC, DIP-28 |
| 文件頁數(shù)： | 7/24頁 |
| 文件大小： | 194K |
| 代理商： | SAA4960 |
1996 Oct 15
7
Philips Semiconductors
Preliminary specification
Integrated PAL comb filter
SAA4960
Internal functional description
S
WITCHED CAPACITOR DELAY LINE
Delays the CVBS input signal by 2 lines and 4 lines. Input
signals for the delay lines are the CVBS signal, the clock
CL3 (3
×
f
sc
), the control signal HSEL and the standard
selection signal SYSPAL.
Output signals are the non-delayed, the 2-line delayed and
the 4-line delayed CVBS signal.
S
WITCHED CAPACITOR
B
AND
-P
ASS
F
ILTERS
(BPF)
The comb filter input BPFs attenuate the low frequencies
to guarantee a correct signal processing within the logical
comb filter.
The comb filter output BPF reduces the alias components
that are the result of the non-linear signal processing within
the logical comb filter.
L
OGICAL COMB FILTER
Separates the chrominance from the band-pass filtered
CVBS signal.
C
OMPENSATION DELAY
Compensates the internal processing time of the
band-pass filters and the logical comb filter section.
A
DDER
The comb filtered luminance output signal is obtained by
adding the delayed CVBS signal and the inverted comb
filtered chrominance signal.
L
OW
-P
ASS
F
ILTER
I
NPUT
(LPFI)
Analog input low-pass filter to reduce the outband
frequencies of EMC. The input low-pass filter is included in
the signal path but it can be switched off via the input
signal LPFION.
L
OW
-P
ASS
F
ILTER
O
UTPUT
(LPFO1
AND
LPFO2)
Two different types of output low-pass filters (LPFO1 and
LPFO2) are necessary to get equal signal delays within the
luminance path and the chrominance path (important for
good transient behaviour). The low-pass output filter type
LPFO1 is used for the luminance output while LPFO2 is
used for the chrominance output. The filters are analog 3
rd
order elliptic low-pass filters that convert the output signals
from the time discrete to the time continuous domain
(reconstruction filter).
LPF
CONTROL
Automatic tuning of the low-pass filters is achieved by
adjusting the filter delays. The control information for all
filters (CONT1 and CONT2) is derived from a built-in
reference filter (LPFO1-type) that is part of a control loop.
The control loop tunes the reference filter delay and thus
all other filter delays to a time constant derived from the
system clock CL3.
C
ONTROL AND CLOCK PROCESSING
(CLOCK CONTROL)
The control and clock processing block (see Fig.7)
consists of the sub-blocks PLL, the clock processing and
the mode control. The PLL and the clock processing are
released for operation if the input level at BYP selects the
COMB-mode.
Main tasks of the control and clock processing are:
Clock generation of system clock CL3
Delay line start control
Mode control.
The signal processing is based on a 3
×
f
sc
system clock
(CL3), that is generated by the clock processing from the
f
sc
signal at FSC (pin 1) via a PLL. Because the subcarrier
frequency divided by the line frequency results not in an
integer value a clock phase correction of 180
°
is necessary
every second line for PAL standards. The clock phase
correction is controlled by the input signals horizontal
sync. Additionally the delay line start is synchronized once
a field to the input signals horizontal sync. The 25 Hz PAL
offset is corrected in this way.
The PLL provides a master clock MCK of 6
×
f
sc
, which is
locked to the subcarrier frequency at FSC (pin 1).
The system clock CL3 (3
×
f
sc
) is obtained from MCK by a
divide-by-two circuit. The 180
°
phase shift is generated by
stopping the divide-by-two circuit for one MCK clock cycle.
The generated clock is a pseudo-line-locked clock that is
referenced to f
sc
. The sync separator generates the
necessary signals H
DET
and V
DET
indicating the line (H)
and the field (V) sync periods.
The current mode of operation (BYPASS or COMB) is
external readable via COMBENA (pin 25).
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SAA4963 | Integrated NTSC comb filter |
| SAA4963T | Integrated NTSC comb filter |
| SAA4970T | Economical video processing IC ECOBENDIC |
| SAA4974 | Besic without ADC |
| SAA4974H | Besic without ADC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SAA4963 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Integrated NTSC comb filter |
| SAA4963T | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Integrated NTSC comb filter |
| SAA4970T | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Economical video processing IC ECOBENDIC |
| SAA4974 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Besic without ADC |
| SAA4974H | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Besic without ADC |
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