The MAX7409 is a digital domain, switched capacitor filter,
not an analog filter.  As such it is subject to aliasing
problems as are all sampled data systems.

On the plus side, it is simple and, being clocked, highly
stable.  Passband frequency and phase responses should be
true Bessel function so group delay distortion should not be
a problem.

Also, Maxim are a great company to deal with, you should
have little trouble sampling a couple of these.

I recently searched for a 1-10 Hz cutoff filter to clean up
the output of a hydraulic pressure transducer in a hydraulic
servo system and came very close to using this part, but
finally settled on a two section R-C low pass filter with
good results.

	Bob Smith


RADIOTEL@....... wrote:
> 
> TO: ALL
> MAXIM has a 5 pole Bessel analog filter (Part # 7409)  which is an 8 pin dip
> package which operates with 5 volts.  Since they only require several
> additional components (resistor and two capacitors) to operate, they would
> appear to be useful for a seismograph.  Has anyone had any experience with
> these filters?  MAXIM's Web address: http://www.maxim-ic.com should you like
> to check it out.
> Jim Allen
> __________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.

-- 

---------  Avoid computer viruses  --  Practice safe hex 
-------------
 * * Specializing in small, cost effective embedded control
systems * *
Robert L. (Bob) Smith			Smith Machine Works, Inc.
internet   bobsmith5@.............. Lumlay Road
landline   804/745-1065	                Richmond, Virginia
23236+1004
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)