adv7344 Analog Devices, Inc., adv7344 Datasheet - Page 52

• Manufacturer Part Number: adv7344
• Description: Multiformat Video Encoder Six 14-bit Noise Shaped Video Dacs
• Manufacturer: Analog Devices, Inc.

ADV7344
FILTERS
Table 39 shows an overview of the programmable filters
available on the ADV7344.
Table 39. Selectable Filters
Filter
SD Luma LPF NTSC
SD Luma LPF PAL
SD Luma Notch NTSC
SD Luma Notch PAL
SD Luma SSAF
SD Luma CIF
SD Luma QCIF
SD Chroma 0.65 MHz
SD Chroma 1.0 MHz
SD Chroma 1.3 MHz
SD Chroma 2.0 MHz
SD Chroma 3.0 MHz
SD Chroma CIF
SD Chroma QCIF
SD PrPb SSAF
ED/HD Chroma Input
ED/HD Sinc Compensation Filter
ED/HD Chroma SSAF
SD Internal Filter Response
Subaddress 0x80, Bits[7:2]; Subaddress 0x82, Bit 0
The Y filter supports several different frequency responses,
including two low-pass responses, two notch responses, an
extended (SSAF) response with or without gain boost
attenuation, a CIF response, and a QCIF response. The PrPb
filter supports several different frequency responses, including
six low-pass responses, a CIF response, and a QCIF response, as
shown in Figure 39 and Figure 40.
If SD SSAF gain is enabled (Subaddress 0x87, Bit 4), there are 13
response options in the −4 dB to +4 dB range. The desired response
can be programmed using Subaddress 0xA2. The variation of
frequency responses are shown in Figure 36 to Figure 38.
In addition to the chroma filters listed in Table 39, the ADV7344
contains an SSAF filter specifically designed for the color difference
component outputs, Pr and Pb. This filter has a cutoff frequency
of ~2.7 MHz and a gain of –40 dB at 3.8 MHz (see Figure 65).
This filter can be controlled with Subaddress 0x82, Bit 0.
Subaddress
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x80
0x82
0x33
0x33
0x33
Rev. 0 | Page 52 of 88
If this filter is disabled, one of the chroma filters shown in Table 40
can be selected and used for the CVBS or luma/chroma signal.
Table 40. Internal Filter Specifications
Filter
Luma LPF NTSC
Luma LPF PAL
Luma Notch NTSC
Luma Notch PAL
Luma SSAF
Luma CIF
Luma QCIF
Chroma 0.65 MHz
Chroma 1.0 MHz
Chroma 1.3 MHz
Chroma 2.0 MHz
Chroma 3.0 MHz
Chroma CIF
Chroma QCIF
1
2
ED/HD Sinc Compensation Filter Response
Subaddress 0x33, Bit 3
The ADV7344 includes a filter designed to counter the effect of
sinc roll-off in DAC 1, DAC 2, and DAC 3 while operating in
ED/HD mode. This filter is enabled by default. It can be
disabled using Subaddress 0x33, Bit 3. The benefit of the filter is
illustrated in Figure 66 and Figure 67.
pass band, measured in dB. The pass band is defined to have 0 Hz to fc (Hz)
frequency limits for a low-pass filter, and 0 Hz to f1 (Hz) and f2 (Hz) to infinity
for a notch filter, where fc, f1, and f2 are the −3 dB points.
Pass-band ripple is the maximum fluctuation from the 0 dB response in the
3 dB bandwidth refers to the −3 dB cutoff frequency.
–10
–20
–30
–40
–50
–60
0
0
1
EXTENDED (SSAF) PrPb FILTER MODE
Figure 65. PrPb SSAF Filter
Pass-Band
Ripple (dB)
0.1
0.04
0.127
Monotonic
Monotonic
Monotonic
0.09
0.048
Monotonic
Monotonic
Monotonic
0.16
0.09
0.1
2
FREQUENCY (MHz)
3
1
4
3 dB Bandwidth (MHz)
4.24
4.81
2.3/4.9/6.6
3.1/5.6/6.4
6.45
3.02
1.5
0.65
1
1.395
2.2
3.2
0.65
0.5
5
6
2