Thank you Chris,

Yes. The ADC can go well above this so all is OK.
I am now set to 20 SPS and will see how I make out.

Thanks Again!!

PauLC





 -----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of ChrisAtUpw@.......
Sent: Tuesday, June 26, 2007 5:40 PM
To: psn-l@..............
Subject: Re: Sample rate on Amaseis??


  In a message dated 2007/06/26, Paulc@........ writes:



    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.


  Hi Paul,

         It is only the AS1 electronics box which is set to 6.15 SPS. The
AS1 has a resonance at 0.67 Hz, so the output falls off sharply above about
2 - 3 Hz

         If you are using a Dataq ADC for instance, you can set the sample
rate to any rate that the board offers, by altering the config file value..


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


         This should be OK, if the ADC can provide it.

         Regards,

         Chris Chapman





Thank=20
you Chris,
 
Yes.=20
The ADC can go well above this so all is OK.
I am=20
now set to 20 SPS and will see how I make out.
 
Thanks=20
Again!!
 
PauLC
 
 
 
 
 
 -----Original =
Message-----
From:=20
psn-l-request@.............. [mailto:psn-l-request@...............On =
Behalf=20
Of ChrisAtUpw@.......
Sent: Tuesday, June 26, 2007 5:40=20
PM
To: psn-l@..............
Subject: Re: Sample rate =
on=20
Amaseis??


In =
a message=20
  dated 2007/06/26, Paulc@........ writes:



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

My Amaseis is =
set to sample at=20
    6 SPS.  This should lead to some interesting aliasing=20
    results.


Hi=20
  Paul,

       It is only the AS1=20
  electronics box which is set to 6.15 SPS. The AS1 has a resonance at =
0.67 Hz,=20
  so the output falls off sharply above about 2 - 3=20
  Hz

       If you are using a =
Dataq ADC=20
  for instance, you can set the sample rate to any rate that the board =
offers,=20
  by altering the config file value..


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

      =
; This=20
  should be OK, if the ADC can provide=20
  it.
      =20
  
      =20
  Regards,

       Chris =
Chapman=20