Xref: utzoo comp.dsp:432 rec.audio:17947
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!umich!yale!husc6!genrad!topo!bickford
From: bickford@topo.UUCP (Peter Bickford)
Newsgroups: comp.dsp,rec.audio
Subject: Re: Stereo synthesis
Summary: Hilbert Transform
Keywords: mono -> stereo
Message-ID: <20495@topo.UUCP>
Date: 9 Jan 90 04:01:55 GMT
References: <768@laic.UUCP>
Sender: st7801::bickford (Peter Bickford)
Reply-To: bickford@topo.UUCP (Peter Bickford)
Organization: GenRad Inc., Milpitas CA
Lines: 19

In article <768@laic.UUCP> trimble@laic.UUCP (Gary Trimble) writes:
>I am interested in taking a "monophonic" source and synthesizing a
>"stereo" like product from it. I can easily design a circut that
>clips high versus low signals but that is really not adequate. Are
>there any papers or articles (or thoughts) on this topic available?

One approach involves filtering out the negative frequencies, thereby
producing a complex (stereo) signal from the original real (mono) signal.

(I think the complex signal is called "the analytic signal" associated
with the given real signal.  (see Papoulis, perhaps.))

An ideal filter would need the signal values for all time.  In practice,
an approximation would permit the use of a FIR filter implementation.

I don't know if this has ever been done in the audio world.
-- 
Peter Bickford
UUCP:		...!sun!topo!bickford