I think this is what is called Stochastic Resonance.
At 21:18 16/04/99 , Bud Hippisley wrote:
>
>Well, there's a name for this effect, which has been documented
>previously in other fields. In my advanced years I can't remember it,
>though. The essence, as I recall, is that the "right" amount of
>background noise can enhance your perception of the desired signal.
>I, too, find it easier to pick weak CW signals out of the noise with
>the 2 kHz SSB filters (stopped down to about 1.2 kHz with the VBT
>control) than with the 500 Hz CW filters at full BW, but I've also
>used the effect (and in fact first noticed it) when trying to analyze
>a strange noise from the car while driving. Turning on the radio and
>having some background music actually enhanced my ability to hear the
>alien noise from the engine compartment. Talk to the psycho-acoustics
>specialists -- they'll know the name of it!
>
>Bud, K2KIR
>
>At 11:07 AM 99/04/16 -0600, you wrote:
>>
>>n6tr@teleport.com wrote:
>>.
>>>
>>> I recently discovered the power of this DSP when doing moonbounce
>>> work on six meters. I have always thought that you had to use really
>>> narrow filters on your receiver to hear weak EME signals. However,
>>> what I found was that it was EASIER to copy weak EME signals using
>>> the SSB bandwidth positions!
>>
>>I've observed the same thing on HF. In the absence of strong QRM, a weak
>>signal is just as easy, or easier, to copy with a wide bandwidth. Since
wide
>>filter bandwidth clearly must reduce the S/N ratio, the effective bandwidth
>>organic DSP must be much smaller. Quite amazing.
>>
>>73,
>>
>>Scott K9MA
>>--
>>
>>
>>Scott Ellington
>>sdelling@facstaff.wisc.edu
>>Madison, Wisconsin USA
>>
>>
>>--
>>CQ-Contest on WWW: http://www.contesting.com/_cq-contest/
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>>
>
>
>--
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>
Justin Snow G4TSH
justin@g4tsh.demon.co.uk
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