# How to narrow the frequency band of a wavelet

I have a ricker wavelet with a dominant frequency of 15 Hz. The fourier transform shows its frequency band is almost to 50 Hz. How can I narrow the frequency band of this 15 Hz ricker wavelet?

I have added a picture of the wavelet and its fftshifted frequency band (The x axis is not the frequency samples).

• Why don't you increase $\sigma$? Or am I missing something? – Matt L. Jan 11 '15 at 13:30
• @MattL.I don't understand, what do you mean by $\sigma$ ? – user3482383 Jan 11 '15 at 13:34
• I'm referring to the definition of the Ricker wavelet as expressed here. – Matt L. Jan 11 '15 at 13:35
• @MattL. does it change the frequency band or dominant frequency? – user3482383 Jan 11 '15 at 13:44
• A larger $\sigma$ makes the wavelet wider in the time domain and narrower in the frequency domain. – Matt L. Jan 11 '15 at 13:55