Frequency Analysis -Sound Forge - PC - MAGIX Community Forums Archive

Subject:Frequency Analysis Posted by: ragj195 Date:2/11/2003 6:12:19 PM I am new to Soundforge and need a little help. I have a .vox file recording of a disconnect tone that a phone system outputs to our voicemail systems. This tone is a single tone with cadence. When opened in Soundforge I need to know the frequency of the tone so I can apply this to our voicemail systems so it can disconnect the call. The tone has an on time of 400ms and an off time of 400ms, how do I find out the frequency of the on time please? Any help is appreciated!
Subject:RE: Frequency Analysis Reply by: Chienworks Date:2/11/2003 6:50:25 PM Probably the most accurate method, assuming this is a simple wave form, is to zoom in far enough to see a few cycles of the wave, say 10 of them, and measure the time in seconds needed for 10 zero crossings (only counting full cycles where the wave goes from negative to positive). Divide this time by 10 to get the time for a single wave, then take the reciprocal of this time to get the frequency. If you have the full version of Sound Forge instead of the Studio/XP version, you can use Tools / Spectrum Analysis. This tool will show the frequency spectrum and indicate the peak frequency. I've found this to be a bit inaccurate though. It seems to be about 2% high most of the time. If this tone is similar to DTMF tones at all, then it's probably made up of two frequencies mixed together. You can still use the first method if you can identifiy the two different wavelengths. The second method may show you both frequency peaks as well, but will probably be less accurate.

Probably the most accurate method, assuming this is a simple wave form, is to zoom in far enough to see a few cycles of the wave, say 10 of them, and measure the time in seconds needed for 10 zero crossings (only counting full cycles where the wave goes from negative to positive). Divide this time by 10 to get the time for a single wave, then take the reciprocal of this time to get the frequency.

If you have the full version of Sound Forge instead of the Studio/XP version, you can use Tools / Spectrum Analysis. This tool will show the frequency spectrum and indicate the peak frequency. I've found this to be a bit inaccurate though. It seems to be about 2% high most of the time.

If this tone is similar to DTMF tones at all, then it's probably made up of two frequencies mixed together. You can still use the first method if you can identifiy the two different wavelengths. The second method may show you both frequency peaks as well, but will probably be less accurate.