On 29 May 2004 04:51:26 -0700, [email protected] (Rune Allnor)
wrote:

>[email protected] (Al) wrote in message news:<[email protected] com>...
>> I have an analog waveform defined in the time domain that I need to
>> detect and measure. I would like to design a matched filter to
>> optimize the signal to noise ratio of the detected waveform.
>>
>> Although the waveform is a pulse, it is rounded on the top and can not
>> really be considered rectangular. The documentation I have been
>> finding seems to just talk about rectangular wave shapes for digital
>> bit detection. I am doing something different; I want to actually
>> measure the pulse area or at least have something proportional to it.
>>
>> Can someone steer me in the direction of some software or technique
>> for designing these types of filters?
>>
>> Thanks. Al
>
>It depends on circumstances, but a matched filter or a Wiener filter
>could perhaps do the job. There are pro's and con's with each class.
>
>The problem with Wiener filters is that they require estimates for
>background noise characteristsics, and might not help at all if you
>get the initial parameters wrong.
>
>The matched filter, which is a FIR filter with impulse resonse like
>the time-reversed waveform you are looking for, does not require
>knowledge of anything else than what you are looking for. However, I
>would imagine the main problem with the matched filter would be
>hich cost, in that it might require a long FIR filter.
>
>FWIW,
>
>Rune

Hi Rune,
maybe Al could decimate his input time sequence
by two, then the filter's length would be
reduced by a factor of two. If his input SNR is
high enough, that might work OK.
I wonder if the signal Al's trying to detect
is symmetrical in time (?). If so, he could
reduce the number of multipliers in his tapped-delay
line FIR filter.

[-Rick-]