Hi Paul,
 
  Both the Dataq software and Amaseis actually run the Dataq 194  at its 
maximum rate of 240 samples per second, and then average the samples down  to the 
user selected rate. This largely eliminates any problem of aliasing. You  are 
free to select whatever recording rate you need to capture the highest  
frequency you want to capture from seismic events. I live on Long Island, New  York, 
and get only teleseisms here, so my recording rate of 5 samples per second  
has been adequate.
 
  The use of Amaseis limits you to one channel. If you ever want to  record 
more than one channel using the Dataq ADC, I urge the use of my software.  See
 
_http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html_ 
(http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html) 
 
Bob McClure
 
On 26 Jun 2007, Paul Cianciolo wrote:
 
I was just thinking about the sample rate for Amaseis.

The preamp  board I have from Larry Cochrane is set to 10 HZ -3db point low
pass  filter.
This means that a minimum sample rate of at least  2x should be  used, I
think according to Mr Nyquist.

My Amaseis is set to sample at  6 SPS.  This should lead to some interesting
aliasing results.

In  the config file I changed the sample rate to 20 SPS and now the Winquake
FFT  window shows  out to 10 Hz.

I have not tested an upload to the PSN  yet.

Any thoughts out there.




************************************** See what's free at http://www.aol.com.





Hi Paul,
 
  Both the Dataq software and Amaseis actually run the Dataq=20=
194=20
at its maximum rate of 240 samples per second, and then average the samples=20=
down=20
to the user selected rate. This largely eliminates any problem of aliasing.=20=
You=20
are free to select whatever recording rate you need to capture the highest=20
frequency you want to capture from seismic events. I live on Long Island, Ne=
w=20
York, and get only teleseisms here, so my recording rate of 5 samples per se=
cond=20
has been adequate.
 
  The use of Amaseis limits you to one channel. If you ever want t=
o=20
record more than one channel using the Dataq ADC, I urge the use of my softw=
are.=20
See
 
=
http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html
 
Bob McClure
 
On 26 Jun 2007, Paul Cianciolo wrote:
 
I was just thinking about the sample rate for Amaseis.

The pream=
p=20
board I have from Larry Cochrane is set to 10 HZ -3db point low
pass=20
filter.
This means that a minimum sample rate of at least  2x should=
 be=20
used, I
think according to Mr Nyquist.

My Amaseis is set to sample=
 at=20
6 SPS.  This should lead to some interesting
aliasing results.
In=20
the config file I changed the sample rate to 20 SPS and now the Winquake
=
FFT=20
window shows  out to 10 Hz.

I have not tested an upload to the P=
SN=20
yet.

Any thoughts out there.



See what's free at AOL.com.