WM8940
Pre-Production
DIGITAL FILTER CHARACTERISTICS
PARAMETER
ADC Filter
TEST CONDITIONS
MIN
TYP
MAX
0.454fs
+/- 0.025
UNIT
Passband
+/- 0.025dB
-6dB
0
0.5fs
Passband Ripple
Stopband
dB
dB
0.546fs
-60
Stopband Attenuation
Group Delay
f > 0.546fs
21/fs
ADC High Pass Filter
High Pass Filter Corner
Frequency
-3dB
3.7
Hz
-0.5dB
10.4
-0.1dB
21.6
DAC Filter
Passband
+/- 0.035dB
-6dB
0
0.454fs
0.5fs
Passband Ripple
Stopband
+/-0.035
dB
dB
0.546fs
-55
Stopband Attenuation
Group Delay
f > 0.546fs
29/fs
Table 61 Digital Filter Characteristics
TERMINOLOGY
1. Stop Band Attenuation (dB) – the degree to which the frequency spectrum is attenuated (outside audio band)
2. Pass-band Ripple – any variation of the frequency response in the pass-band region
3. Note that this delay applies only to the filters and does not include additional delays through other digital circuits. See
Table 62 for the total delay.
PARAMETER
MIN
TYP
MAX
UNIT
Total Delay (ADC analogue
input to digital audio interface
output)
28/fs
30/fs
32/fs
fs
Total Delay (Audio interface
input to DAC analogue
output)
33/fs
35/fs
37/fs
fs
Table 62 Total Group Delay
Notes
1. Wind noise filter is disabled.
Pre-Production, Rev 3.0, February 2007
78
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
