[CW] RE: [MorseCode] binaural I-Q demodulator

[Mike Feher]

Sounds like you are talking about an I/Q modulator. It appears that the
brain becomes the demodulator. Since this is to be done on analog audio
signals it should be real easy to generate quadrature signals by multiplying
the desired input signal by a sine and a cosine wave of the same frequency,
separately. The result would be two signals separated in phase by 90
degrees. The frequency of the multiplying signal needs to be outside of the
frequency band of interest so in reality there will have to be 4 multipliers
and some filters, but, it is a relatively simple concept. It is also known
as the Weaver method or the 3rd method of sideband generation. 73 - Mike    

 
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
 
 

-----Original Message-----
From: morsecode-bounces at mailman.qth.net
[mailto:morsecode-bounces at mailman.qth.net] On Behalf Of David J. Ring, Jr.
Sent: Friday, January 21, 2005 1:20 PM
To: CW at mailman.qth.net
Cc: ~Morsecode
Subject: [MorseCode] binaural I-Q demodulator 


Does anyone have a PDF file of the article written by Rick Campbell, KK7B, 
about a binaural I-Q demodulator which is in
the ARRL Handbook as a weekend project (Chapter 17).

An I-Q demodulator produces two signals, I and Q, that always differ in 
phase by 90°. When you apply those two signals separately to your two ears, 
a spatial-separation effect is produced. The ear-brain combination detects 
the phase (time) delay and signals appear to come from different points in 
space. That is useful because it helps one discern multiple signals more 
clearly.

I know that ARRL is selling the new handbook with a companion CD, and if 
someone could print (by using PDF) the pages of the article.  I have the 
original QST article, but the construction details are not complete.

73

David Ring
N1EA 

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