wm8987 Wolfson Microelectronics plc, wm8987 Datasheet - Page 48

• Manufacturer Part Number: wm8987
• Description: Stereo Codec For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8987L
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DIGITAL FILTER CHARACTERISTICS
Table 44 Digital Filter Characteristics
Table 45 ADC/DAC Digital Filters Group Delay
TERMINOLOGY
1.
2.
Passband
Passband Ripple
Stopband
Stopband Attenuation
Passband
Passband Ripple
Stopband
Stopband Attenuation
High Pass Filter Corner
Frequency
Passband
Passband Ripple
Stopband
Stopband Attenuation
Passband
Passband Ripple
Stopband
Stopband Attenuation
Mode
0 (250 USB)
1 (256/272)
2 (250 USB, 96k mode)
3 (256/272, 88.2/96k mode)
ADC Filter Type 0 (USB Mode, 250fs operation)
ADC Filter Type 1 (USB mode, 272fs or Normal mode operation)
DAC Filter Type 0 (USB mode, 250fs operation)
DAC Filter Type 1 (USB mode, 272fs or Normal mode operation)
Stop Band Attenuation (dB) – the degree to which the frequency spectrum is attenuated (outside audio band)
Pass-band Ripple – any variation of the frequency response in the pass-band region
PARAMETER
DAC FILTERS
The ADC and DAC employ different digital filters. There are 4 types of digital filter, called Type 0, 1, 2
and 3. The performance of Types 0 and 1 is listed in the table below, the responses of all filters is
shown in the proceeding pages.
Group Delay
11/FS
16/FS
4/FS
3/FS
TEST CONDITIONS
f > 0.5465fs
f > 0.5465fs
f > 0.584fs
f > 0.584fs
+/- 0.05dB
+/- 0.05dB
+/- 0.03dB
+/- 0.03dB
-0.5dB
-0.1dB
-6dB
-6dB
-3dB
-6dB
-6dB
Mode
0 (250 USB)
1 (256/272)
2 (250 USB, 96k mode)
3 (256/272, 88.2/96k mode)
0.5465fs
0.5465fs
0.584fs
0.584fs
ADC FILTERS
MIN
-60
-60
-50
-50
0
0
0
0
0.5fs
0.5fs
0.5fs
0.5fs
Group Delay
13/FS
23/FS
4/FS
5/FS
10.4
21.6
TYP
3.7
0.4535fs
0.4535fs
+/- 0.05
+/- 0.05
+/- 0.03
0.416fs
0.416fs
+/-0.03
MAX
PD Rev 4.0 August 2008
UNIT
dB
dB
dB
dB
dB
dB
dB
Hz
dB
Production Data
48