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4.9.1
ADC Filters
4.9.1.1
High Pass Filter
4.9.1.2
Digital Effects Filter - ADC
TLV320AIC34EVM Software
Figure 13. ADC High Pass Filters
The TLV320AIC34 ADC provides the option of enabling a high-pass filter, which helps to reduce the
effects of DC offsets in the system. The
Figure 13
tab shows the options for programming various filter
associated with the ADC. The high-pass filter has two modes: standard and programmable.
The standard high-pass filter option (
Figure 14
) allows for the selection of the high-pass filter frequency
from several preset options that can be chosen with the
Left ADC HP Filter
and
Right ADC HP Filter
controls. The four options for this setting are disabled, or three different corner frequencies which are
based on the ADC sample rate.
Figure 14. ADC Highpass Filter Settings
For custom filter requirements, the programmable function allows custom coefficients to achieve a
different filter than provided by the preset filters. The controls for the programmable high-pass filter are
located under the
Programmable Filters
heading. The process should following the following steps:
1. Enter The filter coefficients can be entered in the
HP Filter
controls near the bottom of the tab.
2. Press the
Download Coefficients
button to download the coefficients to the codec registers.
3. Enable the Programmable High-Pass Filters by selecting the
Left ADC
and
Right ADC
buttons.
The programmable high-pass filter should now be correctly programmed and enabled. The ADC can now
be enabled with the high-pass filter.
The ADC digital outputs stream can be routed through the digital effects filter in the codec to allow custom
audio performance. The digital effects filter cannot operate on both the ADC or DAC at the same time.
The digital effects filter operation is discussed in
Section 4.9.3
SLAU232 – December 2007
TLV320AIC34EVM-K
23
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