PSN-L Email List Message

Subject: amplifier info
From: sean@...........
Date: Sun, 24 Sep 2000 17:45:55 -0500 (CDT)


(Repeat from Sep 11 post:)

For some time I have posted the schematic of the seismic preamp
and 4-pole filter that has been used in over 100 telemetry stations
from Alaska to Greece. The filter design is from the NASA filter 
handbook (details posted).  The schematic shows options for frequency 
scaling, as for a 2.7 second "Wood Anderson Seismometer" response 
that works well in an urban setting (the vault on SLU campus) with
a 15-second long period seis like a Lehman horizontal as input. 
The cmos 4250 amplifiers can be replaced with more available higher 
power devices if battery operation is not needed.
stmmisc.html" PSN INFO ... SLU Seismic Network

Regarding the artwork for the seismic preamp/filter.
I can send a photocopy of the original artwork, 2X scale, black
lines on white or a transparency copy of the actual printing film
(which I doubt is dense enough to photo-print from), if you send 
me three stamps and an address.
It really isn't that complicated, as you can see from the scan
of the foil side of the board shown on the web site. 

And if I were to make only one or two, I would use perforated
board with foil pads. Vector 3677 is 4" wide and has 22 gold plated
edge connectors; cut lengthwise and trimming off one connector makes 
the 2" x 6" to 8", 10-pin connector board that fits inside the tennis-ball 
can that is used for a housing.
I have used this board for as many as 6 prototype circuits; once one is
laid out, duplicating it is easy.


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Larry Cochrane <cochrane@..............>