Low pass interpolation!!

Hi,
I am looking for low pass interpolation filter -  C code or pseudo
code/algorithm descriptions etc. MatLab has one such function
"interp"- the algorithm is described in "programs for digital signal
processing",IEEE Press,1979.
Unfortunately I do not have the book with me.

Could anbody help with online resource.

Regards,
Santosh

On 18 Sep 2003, santosh nath wrote:

> I am looking for low pass interpolation filter -  C code or pseudo
> code/algorithm descriptions etc. MatLab has one such function
> "interp"- the algorithm is described in "programs for digital signal
> processing",IEEE Press,1979.
> Unfortunately I do not have the book with me.

     Try a web search on "Oetken Parks Schussler".

Tak-Shing

santosh nath wrote:
> 
> Hi,
> I am looking for low pass interpolation filter -  C code or pseudo
> code/algorithm descriptions etc. MatLab has one such function
> "interp"- the algorithm is described in "programs for digital signal
> processing",IEEE Press,1979.
> Unfortunately I do not have the book with me.
> 
> Could anbody help with online resource.


Secret Rabbit Code?

    http://www.mega-nerd.com/SRC/

Erik
-- 
+-----------------------------------------------------------+
  Erik de Castro Lopo  nospam@mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"Therapists typically base the nuttiness of a patient on the
strength of their convictions, on which basis this 43,000 word
opus alone stands as a kind of testament to Bill's (Gates)
madness." - The Register

"santosh nath" <santosh.nath@ntlworld.com> wrote in message
news:6afd943a.0309180901.7ca83c48@posting.google.com...
> Hi,
> I am looking for low pass interpolation filter -  C code or pseudo
> code/algorithm descriptions etc. MatLab has one such function
> "interp"- the algorithm is described in "programs for digital signal
> processing",IEEE Press,1979.
> Unfortunately I do not have the book with me.
>
> Could anbody help with online resource.

If you're satisfied with time-domain processing (which isn't necessarily the
fastest method but is simple to implement), you can implement a FIR filter
with coefficients that are obtained from the half-band filter design program
I've posted at:

ftp://ftp.mission-systems-inc.com/outgoing/Halfband/

The filters designed by this program provide 1/2 the bandwidth / 1/4 the
sample rate passband.
So, they are used by zero-filling the time array first and applying the
filter next.
I suppose you could make a polyphase implementation because of all the zero
coefficients in the filter and all of the zeros in the filled time array.

The interpolation can be repeated as above for as many factors of 2 of
interpolation as you may need.  The same filter can be used over and over
for this purpose.

There are more sophisticated and more efficient methods.  This one is
probably the easiest to understand and to implement and debug.

Fred