Digital Signal Processing Reference
In-Depth Information
cancellation filter to the speech signal. Through the DFT, the WOLA
filterbank modulates a single prototype filter into
K
complex filters (
K / 2
unique bands due to Hermitian symmetry). Referring to Figure 10-1, each
subband processing block is generally an adaptive filter working on a
specific frequency band thus modeling a narrow frequency band of the
combined acoustical and electrical transfer functions between the two
microphones.
Figure 10-1.
Block diagram of the SAF system with a Subband Processing Block (SPB) per
subband.
Hybrid Adaptive-Wiener Filtering Enhancement
Method
2.3
In the original SAF system, an adaptive filter is used as the subband
processing block. In the SAFWF, this block is replaced with an adaptive
filter cascaded with a Wiener filter as depicted in Figure 10-3. After
elimination of the correlated noise components by the adaptive filter, the
