On Tue, 1 Aug 2000, Larry Cochrane wrote:
> I found a pretty good book called Analog and Digital Filter Design by Les
> Thede. I got mine at Amazon.com. The description of the book at Amazon said
> it comes with a disk. Actually you need to download it from here
> www.onu.edu/user/FS/lthede/.
> 
> Using this book and the "C" code he supplies, I was able to add time domain
> filtering to WinQuake. The user will be able to do high or low pass
> filtering directly to the data set without having to do a FFT first. This
> and supporting the new PSN format will be the main new features in the next
> release.

There are quite a few books out there on filtering and noise reduction,
especially in the exploration seismology literature.  One of the best general
books on just about every numerical topic with really good supplied routines
is "Numerical Recipes: The Art of Scientific Computing" which covers a great
amount of topics and even goes into the theory behind different numerical
techniques.  The main book is in fortran and pascal, but they have some other
versions in C as well.  The numerical codes are all given as functions or
subroutines, which makes it easy to implement them in an existing code.

There is a good chapter on digital filtering which covers FFT, power spectra,
noise reduction, etc..  They had posted a free copy of an older version of the
book (fortran77) on the web in pdf format.  When I find it again, I'll post
the address to the list.

******************************************************************************
John Hernlund
Department of Geological Sciences
Arizona State University
E-mail: hernlund@.......
WWW: http://www.public.asu.edu/~hernlund/
******************************************************************************

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