fb = hohman2002(fs, flow, basef, fhigh, filters_per_ERBaud)
fs | The sampling frequency of the signals on which the filterbank will operate |
flow | The lowest center frequency of a filter |
basef | "base frequency". One of the filters will have exactly this center frequency. Must be >= flow |
fhigh | The highest center frequency of a filter. Must be >= basef |
filters_per_ERBaud | |
The density of gammatone filters on the ERB scale. |
fb | The constructed filterbank object. |
hohman2002 constructs a new fb object implementing the analysis part of a gammatone filterbank as described in Hohmann (2002).
fb contains several all-pole gammatone filters; each one with a bandwidth of 1 ERB (optional: times bandwidth_factor), and an order of gamma_order.
The center frequencies of the individual filters are computed as described in section 3 of Hohmann (2002).
hohmann2002 takes the following flags at the end of the line of input arguments:
'gamma_order' | The order of the gammatone filters in this filterbank. Default is 4. |
'bandwidth_factor' | The bandwidth parameter of the individual filters is calculated from the Equivalent Rectangular Bandwidth (ERB) according to equation 14 in Hohmann (2002). ERB is taken from the Glasberg & Moore formula for a specific center frequency (equation 13 in Hohmann (2002)). Using this parameter, it is possible to widen or narrow all filters of the filterbank with a constant bandwidth factor. Default is 1.0 |
'l' | Scaling factor l from Eq. 13 in Hohmann (2002). Default is 24.7. |
'q' | Scaling factor q from Eq. 13 in Hohmann (2002). Default is 9.265. |
V. Hohmann. Frequency analysis and synthesis using a gammatone filterbank. Acta Acustica united with Acoustica, 88(3):433--442, 2002.