freq = erbtofreq(erb);
This is a wrapper around audtofreq that selects the erb-scale. Please see the help on audtofreq for more information.
The following figure shows the corresponding frequencies for erb values up to 31:
erbs=0:31; freqs=erbtofreq(erbs); plot(erbs,freqs); xlabel('Frequency / erb'); ylabel('Frequency / Hz');