[Top] [All Lists]

Re: anti-aliasing without filter?

Subject: Re: anti-aliasing without filter?
From: Gianni Pavan <>
Date: Mon, 10 May 2004 12:32:00 -0700
<tt>Yes, it makes sense. Though, you must be sure nothing enters into your 
 electroacoustic chain.  Other than real sounds, you also have also to 
 consider any electric interference coming from the environment in 
 which you're working.</tt><br>
 <tt>Just as an example, while working on an oceanographic ship I needed to 
 sample wideband hydrophones at 1 MHz to avoid aliasing due to heavy 
 interference in the range 200 to 400 kHz. Then I filtered out unwanted 
 frequencies by using software filters, and the final step was 
 <tt>Depending on the equipment you have and the context in which you're 
 working, oversampling can be a solution to avoid the use of expensive analog 
 filters (sharp filters at very high frequency are normally expensive!). An 
 additional positive effect of oversampling is a reduction of quantization 
 noise when using industrial boards with 12 or 14 bits of resolution.</tt><br>
 <pre style="margin: 0em;">Gianni
 [EMAIL PROTECTED]</pre><br>
 <pre style="margin: 
 Gianni Pavan
 Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
 Universita' degli Studi di Pavia
 Via Taramelli 24, 27100 PAVIA, ITALIA
 Tel        +39-0382-507874
 Fax        +39-02-700-32921
 Web       <a  href=""; 
 <tt><br>At 17.26 10/05/2004, you wrote:
 </tt><blockquote style="border-left: #0000FF solid 0.1em; margin: 0em; 
padding-left: 1.0em"><pre style="margin: 0em;">Does anyone can point out 
problems or disadvantages of
 using the frequency response of transducers and/or
 amplifiers (e.g. due to GBP limitations) to avoid
 <pre style="margin: 0em;">If for instance I use a transducer with a response
 that drops past 100 kHz and an amplifier with a
 similar frequency response, and I sample my signal at
 500 kHz, I could avoid aliasing without having to use
 a low pass filter before the analog-to-digital stage.
 Does this makes sense?</pre><br>
 <tt>All the best,</tt><br>
 <tt>Ricardo Antunes

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the Bioacoustics-L mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU