Chris,
With all due respect, there is no GMT daylight time. It's called BST or British
Summer Time is it not? Whitch is equivalent to what we in the US call daylight
saving time. In the interest of preserving traditon, let us not conemplate the
alteration of traditional forms of reference. We do not need to assist all of
the "multicultural" nutcases out there waiting to stab us the back.
Erich Kern


-----Original Message-----
From: ChrisAtUpw@....... 
To: psn-l@.............. 
Date: Tuesday, September 12, 2000 5:50 PM
Subject: Re: Preamp-Filter Modifications


In a message dated 12/09/00 15:43:20 GMT Daylight Time, jmhannon@........
writes:

> The second two 0.1 UF capacitors associated with the second
> filter op amp should be changed to 0.0991 UF. You will
> need to measure and test select the capacitors and possibly parallel parts
> to get within at least 5% of the values specified.

Jim,

    ??? Sorry, but I don't quite understand. 0.0991 UF is within 1% of 0.1
UF.

> The 1 Hz design is easily changed to any other frequency within
> reason by dividing the value of the 4 1 Meg Ohm resistors by the
> desired frequency. For example if you want a 5 Hz low pass filter
> you would use 200K resistors instead of 1 Meg.

    Where is the 4.1 M Ohm coming from? The diagram of the four pole filter
gives pairs of 1.6 M Ohm input resistors. Can you confirm the R value for 1
Hz please?

    Regards,

    Chris Chapman
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)



__________________________________________________________

Public Seismic Network Mailing List (PSN-L)