WM8608 ETC-unknow, WM8608 Datasheet - Page 41

• Manufacturer Part Number: WM8608
• Description: The Wm8608 Comprises A High Performance Multi-channel Pwm Digital Power Amplifier Controller. Simply By Adding Appropriate Power Output Stages A Multi-channel Power Amplifier May Be Built. Six Identical Full Audio Bandwidth Channels, Plus A Reduced B
• Manufacturer: ETC-unknow

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INTERPOLATION FILTERS
Table 42 Digital Filter 0 Characteristics
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PARAMETER
Filter
Passband
Stopband
Passband ripple
Stopband Attenuation
Group Delay
ZERO-CROSS DETECT
The Dynamic Peak Compressor has a zero-cross detect that minimises clicks during gain changes.
The zero-cross detect can be enabled/disabled in channel-pairs. The zero-cross has a timeout
feature which ensures that the volume will change even if the input has a large DC offset. Once a
new gain has been requested from the Dynamic Peak Compressor, the zero-cross detector will wait
for a zero-cross for 25 to 50 ms before applying the gain change.
Note that the zero-cross settings programmed here also apply to the Dynamic Peak Compressor.
Table 40 Volume Control Zero-Cross
The WM8608 uses two types of interpolation filters, selected according to sampling frequency, as
shown in Table 40.
Table 41 Interpolation Filter Types
Note: If the Subwoofer channel is redirected into the Rear Centre (RC) channel the main channel
characteristics apply.
FILTER TYPE 0
R25 (19h)
Volume
Control Zero-
Cross
SAMPLING FREQUENCY
REGISTER
ADDRESS
SYMBOL
176.4kHz
44.1kHz
88.2kHz
192kHz
32kHz
48kHz
96kHz
BIT
0
1
2
3
4
TEST CONDITIONS
f > 0.546fs
0.05 dB
-3dB
ZCSUB
LABEL
ZCS
ZCC
ZCF
ZCT
Main Channels
FILTER TYPE
0
0
0
0
0
1
1
DEFAULT
MIN
-60
23
1
1
1
1
1
Main Channels
INTERPOLATION
12x
8x
8x
4x
4x
2x
2x
Zero-Cross Enable – Front Channels:
Zero-Cross Enable – Surround
Channels:
Zero-Cross Enable – Front Centre and
Rear Centre Channels:
Zero-Cross Enable – Sub Channel:
Zero Cross Timeout Enable:
0.484
TYP
0 : Disable Zero-Cross
1:
0 : Disable Zero-Cross
1:
0 : Disable Zero-Cross
1:
0 : Disable Zero-Cross
1:
0 : Disable Zero-Cross Timeout
1:
Enable Zero-Cross
Enable Zero-Cross
Enable Zero-Cross
Enable Zero-Cross
Enable Zero-Cross Timeout
DESCRIPTION
SUB
6x
4x
4x
2x
2x
1x
1x
PP Rev 1.5 March 2004
0.454
MAX
0.05
WM8608
samples
UNIT
dB
dB
f
f
s
s
41