The Swezey Digital Filter
Automatic Heterodyne Tone ("Whistles") Removal
One of the most annoying problems in short wave listening is the presence of heterodyne tones ("whistles").
For example shortwave stations may be placed 5 Khz apart. When this happens the carrier signal of one station
will appear as a steady 5 kHz tone when tunning in the other station.
To correct for this I have developed an algorithm in the program that looks for sustained tones and reduces them significantly.
Below is a brief excerpt from a
Radio Australia
news program.
To hear (or download) the unfiltered "before" version
Click Here!
To hear (or download) the filtered "after" version
Click Here!
Both excerpts are MPEG mp3 audio files. If you need help playing these files
Click Here!
Thank you for your interest in my program!
Your comments are always welcome,
please e-mail me at
swezeyt@winternet.com
(c) 2008, Thomas F. Swezey. All rights reserved.