It is very valuable for a classification tool
and seeing events even too small to measure.
They are signals within the grass.


----- Original Message ----- 
From: "Larry Conklin" 
To: 
Sent: Tuesday, December 29, 2009 2:16 PM
Subject: Re: Sensor noise


> Hi Barry,
> 
> It sounds like you've been messing around with something similar to a 
> project I started but didn't get around to finishing.  I added a 
> waterfall FFT plot to my data logging program, but never finished 
> debugging it.  In part because I wasn't all that confident that the plot 
> would be worth all that much.
> 
> I'd be interested in a little more information regarding how you are 
> collecting the FFT and some of the design decisions you use (number of 
> samples in the window, how frequently you do a conversion, etc.)  Did 
> you write your own code or are you using some 3'rd party software?
> 
> Larry Conklin
> Liverpool, NY
> lconklin@............
> 
> 
> On 12/29/2009 12:12 AM, Barry Lotz wrote:
>> All
>> I have successfully used a running fft to sense signal frequency
>> component changes and used this as a trigger mechanism for an event.
>> Could one use the ( I guess you call it ) power spectrum of the signal
>> just before and during the event to remove the noise? I guess you would
>> have to use the same time window so the frequencies would compare. Could
>> it be a simple subtraction of the "before" from the "during"? This would
>> assume that the background noise didn't change in the period during an
>> event. This could be better than trying to shape a multi pole filter to
>> eliminate the noise. I have found that often a portion of the event
>> signal is in the same frequency range as the noise.
>>
>> Regards
>> Barry
>> http://www.seismicvault.com
>>
> __________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email PSN-L-REQUEST@.............. with 
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)