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 downsampling.
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.
Gianni [EMAIL PROTECTED]
-------------------------------------------------------------- Gianni Pavan Email [EMAIL PROTECTED] 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 http://www.unipv.it/cibra
At 17.26 10/05/2004, you wrote:
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 aliasing?
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?
All the best,
Ricardo Antunes
