signal noise and filters

[wyndham]

I read Eric's question on the amt of filtering that has to be done to get a clean signal on the PI.
This is a bit off the wall but I'll stick my neck out and venture an idea.
The white noise that we see when our televisions are on a non transmitting channel has been partially atributed to the background radiation noise from deep space that is constantly comming into our planet. It comes from everywhere.
Can this be the source of some, not all, the noise that has to be filtered out?
Maybe it is not a direct noise but the reflection back from what the earth has recieved. Sorta like a tx coil but never shutting off.
Further out yet, the moon could block or cause a shadow that could give a different signal through the lessened noise and be percieved as working better on a full moon.
It would be an interesting test to record the output signal and view it on a music software program, where some of the software band pass filters could be used to see where and what is going on.
I have Cakewalk's "Sonar" program and can import wav, mpg3 or midi files.
Eric and all, if you would like to follow up on this,please let me know. there are many good sound programs that will do this. The advantage I see is that you have a record and can try different ideas without being at the moment with a scope.
This may well be old ideas and just new to me. Later Wyndham

 

[bcarey]

--wyndhan, I think you have to consider a couple of things with a white noise theory. the first consideration is the amplitude flatness and the width of the band. The bands from outer space are in the 44GHz to 250 KHz with a resoultion variance of .001Hz. It is quite possible to measure the variances with a music type program or oscilloscope type of instrument. Whatever signal gets thru to your "sonar" program can be measured for spectural purity. you can inject special parameters, as you have suggested, with different filters to measure functionality of complex modulated signals.
The second thing to be considered is that there is a lot of sideband noise due to the radiation. There are some filters that can help with this noise using baseband algorithms.
I would think Eric would have all this figured out by now. tks bruce

 

[wyndham]

Bcarey, sometimes the better way for me to learn about something(PI'S) is to put forth an idea and in the response find out where there is any leg to stand on.
The most I have ever done is solder some mic leads on a sound system. I have no understanding of the hardware part of a PI other than understanding that as good as it is today, It seems to me that there is something missing. I'm sure that this idea is from my lack of knowledge about the signal and response from the target.
I hold on to too many false ideas on how things should work But remember the movie "African Queen" when Boagart was pulling the boat thru the reeds and the river channel was just 100yd or so away parallel to his position, My, maybe false idea is that we are in a sea of noise and we are working harder than the avg bear, when just accross the road is a better way.
I'm sure Eric has run this rabbit many times in his sleep, but I also believe that unless new,wrong,misguided thoughts are introduced, new solid branches do not spring out.
What I am, in a roundabout way suggesting, is a software filter that is captured and subtracted in real time and that the Sound software has the luxury of playing with different setting or filters to see how the signal behaves.
As to the Big Bang low level radiation, It might be the sun charging the earth or some other combo of effects but the nut of it is to find the common ground that causes the effect and delete it. I don't know, maybe a DSP daughter board that can be adapted from some on Circuit cellar magazine might have filters that have not been tried.
Eric, I also realize that you invented the PI and without this forum, I would never have found out what I have so far.
Please don't look at this as a rant but a zeal to help discover the next level of PI that is out there.
In my ignorance, my suggestion might have a thread that might be worth a look at exploring.
Thanks Wyndham