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Passband filtering, Table 13. sample rate converter – Rainbow Electronics MAX98088 User Manual

Page 85

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Stereo Audio Codec

with FLEXSOUND Technology

MAX98088

85

Table 13. Sample Rate Converter

Figure 19. Digital Passband Filtering Block Diagram

Passband Filtering

Each digital signal path in the IC includes options for
defining the path bandwidth (Figure 19). The playback
and record paths connected to DAI1 support both voice
and music filtering while the playback path connected to
DAI2 supports music filtering only.
The voice IIR filters provide greater than 70dB stopband
attenuation at frequencies above f

S

/2 to reduce aliasing.

Three selectable highpass filters eliminate unwanted
low-frequency signals.

Use music mode when processing high-fidelity audio
content. The music FIR filters reduce power consump-
tion and are linear phase to maintain stereo imaging.
An optional DC-blocking filter is available to eliminate
unwanted DC offset.
In music mode, a second set of FIR filters are available
to support sample rates greater than 50kHz. The filters
can be independently selected for DAI1 and DAI2 and
support both the playback and record audio paths.

REGISTER

BIT

NAME

DESCRIPTION

0x21

4

SRMIX_MODE

Sample Rate Mix Mode
0 = (DAI1 + DAI2)
1 = (DAI1 + DAI2)/2

3

SRMIX_ENL

Sample Rate Mix Enable
0 = SRC mix disable
1 = SRC mix enable

2

SRMIX_ENR

1

SRC_ENL

Sample Rate Converter Enable
0 = Sample rate converter disable
1 = Sample rate converter enable

0

SRC_ENR

DSTS

SIDETONE

DVST:
0dB TO -60dB

AUTOMATIC

GAIN

CONTROL

EQ1EN

EQ2EN

DVEQ1:
0dB TO -15dB

DV1G:
0/6/12/18dB

DV2:
0dB TO -15dB

DCB2

5-BAND

PARAMETRIC

EQ

5-BAND

PARAMETRIC

EQ

DVEQ2:
0dB TO -15dB

MULTI BAND ALC

EXCURSION LIMITER

DV1:
0dB TO -15dB

MODE1
DVFLT

DALEN

MIXDAR

DACL

DAREN

DACR

+

NOISE GATE

MODE1

AVFLT

SRMIX_

MODE

AVLG: 0/6/

12/18dB

AVL:0dB

TO -15dB

AVRG: 0/6/
12/18dB
AVR:0dB
TO -15dB

AUDIO/

VOICE

FILTERS

AUDIO/

FILTERS

AUDIO/

VOICE

FILTERS

MIX

MIX

MIXDAL

MIX

ADREN

ADLEN

ADCR

ADCL

SAMPLE RATE

CONVERTER