In a message dated 2007/08/14, dickthomas01@............. writes:

> It helps when you take the extra spaces out of the end .... I had read this 
> article earlier. I have spent the whole time since our last email trying to 
> get rid of that peak at 4 Hz. I took the jumpers in and out I went from one 
> end of the pot to the other ... still trying... 

Hi Tom,

       The peaks could either be real, which I suspect, aldhough I don't 
understand how they would be generated.
       Alternatively, they might be due to inadequate damping of the 
geophones and their responding resonantly to noise. However, I would expect that they 
would have top be grossly underdamped to produce the effect. 
       They might also be of a higher frequency leaking a subharmonic past 
the low pass filter, but they would need to be large to start with.

       Regards,

       Chris
   
In a me=
ssage dated 2007/08/14, dickthomas01@............. writes:



It helps when you take the extr=
a spaces out of the end .... I had read this article earlier. I have spent t=
he whole time since our last email trying to get rid of that peak at 4 Hz. I=
 took the jumpers in and out I went from one end of the pot to the other ...=
 still trying... 




Hi Tom,



       The peaks could either be real, which I=
 suspect, aldhough I don't understand how they would be generated.

       Alternatively, they might be due to ina=
dequate damping of the geophones and their responding resonantly to noise. H=
owever, I would expect that they would have top be grossly underdamped to pr=
oduce the effect. 

       They might also be of a higher frequenc=
y leaking a subharmonic past the low pass filter, but they would need to be=20=
large to start with.



       Regards,



       Chris