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Re: Secondary Harmonics

Subject: Re: Secondary Harmonics
From: "Raimund Specht" <>
Date: Tue, 03 Jun 2003 23:15:18 -0000
Walter Knapp wrote:
> The harmonics can also not exist at all, but be a result of the 
math 
> that created the sonogram. In which case filtering will make no 
> difference at all. Not everything on a sonogram is really there. 
Not 
> only are there false "harmonics",

Yes, real-time spectrogram applications may add spurious harmonics 
because they need to use simpler algorithms in order to execute fast 
enough on slower machines. However, a good off-line spectrogram 
software should not introduce any false harmonics. 

> but a lot of the spatter around a loud 
> call is not there either. 

These "side lobes" can be reduced by using either a Flattop or a 
Blackman window instead of the common Hamming window.

Regards,
Raimund




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