Datasheet
TLV320AIC3120
SLAS653A –FEBRUARY 2010–REVISED MAY 2012
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Table 5-15. ADC FIR Filter Coefficients (continued)
Filter Coefficient FIlter Coefficient RAM Location Default (Reset) Values
(1)
Fir12 Page 4 / register 38 and page 4 / register 39 0x0000
Fir13 Page 4 / register 40 and page 4 / register 41 0x0000
Fir14 Page 4 / register 42 and page 4 / register 43 0x0000
Fir15 Page 4 / register 44 and page 4 / register 45 0x7FFF (decimal 1.0 – LSB value)
Fir16 Page 4 / register 46 and page 4 / register 47 0x0000
Fir17 Page 4 / register 48 and page 4 / register 49 0x0000
Fir18 Page 4 / register 50 and page 4 / register 51 0x0000
Fir19 Page 4 / register 52 and page 4 / register 53 0x0000
Fir20 Page 4 / register 54 and page 4 / register 55 0x7FFF (decimal 1.0 – LSB value)
Fir21 Page 4 / register 56 and page 4 / register 57 0x0000
Fir22 Page 4 / register 58 and page 4 / register 59 0x0000
Fir23 Page 4 / register 60 and page 4 / register 61 0x0000
Fir24 Page 4 / register 62 and page 4 / register 63 0x0000
5.5.4.4 ADC Digital Decimation Filter Characteristics
The TLV320AIC3120 offers three different types of decimation filters. The integrated digital decimation
filter removes high-frequency content and downsamples the audio data from an initial sampling rate of
AOSR × f
S
to the final output sampling rate of f
S
. The decimation filtering is achieved using a higher-order
CIC filter followed by linear-phase FIR filters. The decimation filter cannot be chosen by itself; it is implicitly
set through the chosen processing block.
The following subsections describe the properties of the available filters A, B, and C.
5.5.4.4.1 Decimation Filter A
This filter is intended for use at sampling rates up to 48 kHz. When configuring this filter, the oversampling
ratio of the ADC can either be 128 or 64. For highest performance, the oversampling ratio must be set
to 128.
Filter A can also be used for 96 kHz at an AOSR of 64.
Table 5-16. ADC Decimation Filter A, Specification
Parameter Condition Value (Typical) Unit
AOSR = 128
Filter-gain pass band 0…0.39 f
S
0.062 dB
Filter-gain stop band 0.55…64 f
S
–73 dB
Filter group delay 17/f
S
s
Pass-band ripple, 8 ksps 0…0.39 f
S
0.062 dB
Pass-band ripple, 44.1 ksps 0…0.39 f
S
0.05 dB
Pass-band ripple, 48 ksps 0…0.39 f
S
0.05 dB
AOSR = 64
Filter-gain pass band 0…0.39 f
S
0.062 dB
Filter-gain stop band 0.55…32 f
S
–73 dB
Filter group delay 17/f
S
s
Pass-band ripple, 8 ksps 0…0.39 f
S
0.062 dB
Pass-band ripple, 44.1 ksps 0…0.39 f
S
0.05 dB
Pass-band ripple, 48 ksps 0…0.39 f
S
0.05 dB
Pass-band ripple, 96 ksps 0…20 kHz 0.1 dB
34 APPLICATION INFORMATION Copyright © 2010–2012, Texas Instruments Incorporated
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