getCenterFrequencies

Center frequencies of filters

Syntax

cf = getCenterFrequencies(obj)

Description

cf = getCenterFrequencies(obj) returns the center frequencies of the filters created by obj, in Hz.

Examples

Center Frequencies of gammatoneFilterBank

Create a gammatoneFilterBank and get the center frequencies of the filters in the filter bank.

gammaFiltBank = gammatoneFilterBank;

cf = getCenterFrequencies(gammaFiltBank)

cf = 1×32
103 ×

    0.0500    0.0822    0.1180    0.1581    0.2027    0.2525    0.3080    0.3700    0.4390    0.5161    0.6020    0.6979    0.8048    0.9241    1.0571    1.2054    1.3709    1.5555    1.7613    1.9909    2.2470    2.5327    2.8513    3.2066    3.6030    4.0451    4.5381    5.0881    5.7015    6.3857    7.1488    8.0000

Center frequencies of a gammatone filter bank are spaced evenly on the ERB scale. Convert the center frequencies vector to the ERB scale and calculate the differences between center frequencies.

diff(hz2erb(cf))

ans = 1×31

    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116    1.0116

Center Frequencies of octaveFilterBank

Create an octaveFilterBank and get the center frequencies of the filters in the filter bank.

octFiltBank = octaveFilterBank;

cf = getCenterFrequencies(octFiltBank)

cf = 1×10
104 ×

    0.0032    0.0063    0.0126    0.0251    0.0501    0.1000    0.1995    0.3981    0.7943    1.5729

Center frequencies of an octave filter bank are spaced evenly on a logarithmic scale. Convert the center frequencies vector to the log scale and calculate the differences between center frequencies.

diff(log10(cf))

ans = 1×9

    0.3000    0.3000    0.3000    0.3000    0.3000    0.3000    0.3000    0.3000    0.2967

Get Center Frequencies of Octave Filter Bank Used in splMeter

Create an octave bandwidth splMeter and get the center frequencies of the octave filter bank. Round the center frequencies to two significant digits for display purposes.

SPL = splMeter('SampleRate',44100,'Bandwidth','1 octave');
cf = getCenterFrequencies(SPL);
round(cf,2,'significant')

ans = 1×10

          32          63         130         250         500        1000        2000        4000        7900       16000

Input Arguments

obj — Object to get filter bank center frequencies from

gammatoneFilterBank | octaveFilterBank | splMeter

Object to get filter bank center frequencies from, specified as an object of gammatoneFilterBank, octaveFilterBank, or splMeter.

Output Arguments

cf — Filter bank center frequencies (Hz)

scalar | vector

Filter bank center frequencies in Hz, returned a scalar or vector.