55.6.2.5 High Pass Filter

The PDMIC includes an optional first-order IIR filter performing a high pass transfer function after the low pass filter and before the decimation. The coefficients are computed for a decimated sampling rate of 48 kHz to obtain a -3dB cutoff frequency at 15 Hz.

If the decimated sampling rate is modified, the frequency response of this filter is scaled proportionally to the new frequency.

This filter can be bypassed by setting the HPFBYP bit in PDMIC_DSPR0 (see PDMIC_DSPR0).

Figure 55-9 is drawn for an output sampling frequency of 48 kHz.

Figure 55-9. High Pass Filter Spectral Mask in the 0 to 100 Hz Band