5 Mar
2007
5 Mar
'07
7:31 p.m.
Hallo, Kyle Klipowicz hat gesagt: // Kyle Klipowicz wrote:
Could aliasing be avoided by using a multi-pole low pass filter at nyquist before sending the signal to the dac?
No: Alias frequencies aren't too high, they are wrong frequencies, that have been mirrored at the Nyquist border. As soon as you try to play a sinewave at Nyquist + x, what you get is a sine at Nyquist - x, and you cannot lowpass out this frequency after it has been introduced.
You can however upsample your signal first, then use a lowpass filter, then downsample again. See this chapter in The Book for more info: http://crca.ucsd.edu/~msp/techniques/latest/book-html/node194.html and J07.oversampling.pd
Ciao
Frank Barknecht _ ______footils.org_ __goto10.org__