JAJSNO6 December 2023 TAC5142
ADVANCE INFORMATION
To remove the DC offset component and attenuate the undesired low-frequency noise content in the record data, the device supports a configurable high-pass filter (HPF) with –3-dB cut-off frequency of 0.000021 × fS or 0.00025 × fS. The HPF is not a channel-independent filter but is globally applicable for all the ADC channels. This HPF is constructed using the first-order infinite impulse response (IIR) filter, and is efficient enough to filter out possible DC components of the signal. This configuration is only available in I2S or LJF Target mode of operation. In Target TDM Mode of operation, MD3 is used to set slot for input and output data streams. Refer to section for more details on Daisy chain features. In Controller Mode, MD3 is used as CCLK input and HPF is by default set to 0.000021 × fS. Additionally, As lower frequency filter in digital requires higher value capacitor as well for low droop at cutoff frequency, the device also adjusts the quick charge time along with HPF cutoff with this configuration. Table 8-8 shows the MD3 configuration and –3-dB cutoff frequency value and quick charge time.
MD3 | –3-dB CUTOFF FREQUENCY VALUE | QUICK CHARGE TIME | -3-dB CUTTOFF FREQUENCY AT 48 kHz SAMPLE RATE |
---|---|---|---|
Low | 0.000021 × fS | 50 ms | 1 Hz |
High | 0.00025 × fS | 12.5 ms | 12 Hz |