To those inquiring about my program:

DrumPlot is not a data acquisition program.  It can only read, filter, and 
display data files that are acquired using Dataq hardware and software.  I 
use the DI-194 starter kit and the software supplied with the board.  The 
files generated have the extension WDQ.

  The DI-194 samples data at at a fixed rate of 240 s/s with 8-bit 
conversion.  It appears to have more precision at slower sampling rates 
because the Dataq acquisition program averages all the data points sampled at 
the 240/s rate that fall within the slower recorded sampling interval.  This 
works pretty well for me, since I sample at 5 s/s, get the benefit of the 
average of 48 actual samples per recorded sample, which, if the signal is 
dynamic enough, washes out the quantitization error.  For sensors with very 
short natural periods, such as geophones, you must sample at higher rates 
than 5 s/s, and will end up closer to the basic  8-bit resolution than the 
DI-194 will provide.  For more resolution, you need the DI-154 with 12-bit 
resolution at 240 s/s, so you still have at least 12 bits at any rate, and an 
effective maximum of  14 bits at lower recorded rates.  This is still less 
than one might wish for.  You also get a little less for your money now.  
Dataq raised the price of the DI-194 from less than $15 to $24.  The DI-154 
went from about $100 to $150 (+$8.55 shipping).

  The filters in my program can still be used at high sampling rates on a 
short period instrument, but the default time constants I use will have to be 
reduced.  If you can get the program to work in the way you desire with user 
input time constants, I can furnish a revised program with different 
defaults, or change the program to remember your defaults in a setup 
operation.

  Also note that the inverse filter used to extend the effective period is 
based on the passive type of sensor, whose output voltage is proportional to 
the velocity of a damped pendulum.

Bob McClure
bobhelenmcclure@.......
To those inquiring about my program:



DrumPlot is not a data acquisition program.  It can only read, filter, and display data files that are acquired using 
Dataq hardware and software.  I use the DI-194 starter kit and the software supplied with the board.  The files gener
ated have the extension WDQ.



  The DI-194 samples data at at a fixed rate of 240 s/s with 8-bit conversion.  It appears to have more precision
 at slower sampling rates because the Dataq acquisition program averages all the data points sampled at the 240/s rate that fal
l within the slower recorded sampling interval.  This works pretty well for me, since I sample at 5 s/s, get the benefit o
f the average of 48 actual samples per recorded sample, which, if the signal is dynamic enough, washes out the quantitization e
rror.  For sensors with very short natural periods, such as geophones, you must sample at higher rates than 5 s/s, and wil
l end up closer to the basic  8-bit resolution than the DI-194 will provide.  For more resolution, you need the DI-15
4 with 12-bit resolution at 240 s/s, so you still have at least 12 bits at any rate, and an effective maximum of  14 bits 
at lower recorded rates.  This is still less than one might wish for.  You also get a little less for your money now.
  Dataq raised the price of the DI-194 from less than $15 to $24.  The DI-154 went from about $100 to $150 (+$8.55 sh
ipping).



  The filters in my program can still be used at high sampling rates on a short period instrument, but the default tim
e constants I use will have to be reduced.  If you can get the program to work in the way you desire with user input time 
constants, I can furnish a revised program with different defaults, or change the program to remember your defaults in a setup 
operation.



  Also note that the inverse filter used to extend the effective period is based on the passive type of sensor, whose 
output voltage is proportional to the velocity of a damped pendulum.



Bob McClure

bobhelenmcclure@.......