> How can one easily do a 90 degree phase-shift on a signal?
> 
	You can't, unless you can describe all of the frequency components
exactly.  The closest you could probably get is to take an FFT and shift
all of the phases by pi/2.
	If you know the frequency of the signal, you can delay it by 1/4 of the
wavelength.  But this only shifts the fundamental by 90 degrees.  Every
partial is going to be shifted by some multiple of 90.

-- 
Mike Berry
mikeb@nmol.com
http://www.nmol.com/users/mikeb

>> How can one easily do a 90 degree phase-shift on a signal?
>> 
>You can't, unless you can describe all of the frequency components
>exactly.  The closest you could probably get is to take an FFT and shift

Ok, so there are no easy way as it is with a 180° phaseshift?
When encoding for dolby-surround, the "surround" signal has to
be splitted and phaseshifted +90 and -90 degrees.
I heard that it's not really ok to leave one and shift the other by 180°.

.--- -- -  -
| Anders "Pipe/Nature" Andersson, pipe@algonet.se
: