Topband: Signals in noise

Bob Eldridge r.c.eldridge at ieee.org
Mon Mar 29 21:50:32 EST 2004


Hi Jerry:
Tried to send this privately, but Earthlink dumped it in your "suspect" box.

At 10:09 2004-03-27 -0800, you wrote:
>There is an interesting article in Chinese Physics Letters Vol. 21, No. 4,
>p. 757 regarding enhancing detection of single tones by adding noise.

Jerry:
Indeed an interesting article. But it seems to me it refers to making a 
very low amplitude signal (one too weak to hear, not one too masked by QRN) 
audible by bringing the totality up to perceptible level. Not by winkling 
out a signal that is buried in noise by adding white noise to the S + N.
I have adjustable level white noise on the Hildreth filter, and sometimes 
use it to mask intelligible weak QRM. I haven't really tried reducing the 
audio to almost imperceptible level before adding the white noise, but I 
will. It makes sense that white noise modulated by the signal will be 
perceptible, and I have to find out what it sounds like.
It may be like hearing your callsign in the wind.

Bob VE7BS



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