FPGA Central

To all the members of this community,
iam doing my project on ultrasonic signal processing.
i need to design a matched filter,to remove the white noise from th
received signal(it is the signal received by ultrasonic receiver sensor).
as iam having very little knowledge about signal processing i dont kno
how to design a matched filter practically for a given frequency aroun
40KLHz.The only thing that i know about matched filter is that it perform
mathematical convolution function.
CAn anybody help me to do that?

On 25 Mar, 11:59, "vimmi" <vimal.veeren...@gmail.com> wrote:
> To all the members of this community,
> iam doing my project on ultrasonic signal processing.
> i need to design a matched filter,to remove the white noise from the
> received signal(it is the signal received by ultrasonic receiver sensor).
> as iam having very little knowledge about signal processing i dont know
> how to design a matched filter practically for a given frequency around
> 40KLHz.The only thing that i know about matched filter is that it performs
> mathematical convolution function.

No, it doesn't. First of all, read up on DSP.

After having done that, you need to find out
exactly what signal you look for. A 'matched
filter' is exactly that - matched - so you can't
use any filter with any signal.

In other words, you need a lot of information:

- The nominal pulse as emitted by the transmitter
signal generator
- Any distorsions of that pulse through the transducer
and into the medium under measurement
- Any distorsions of the recieved pulse through
the reciever

Only when you have a clear idea of these factors do you
know what signal your matched filter should look for.

In addition, you might have to compensate for non-linear
effects, if this is high-power systems.

Rune

Rune Allnor wrote:
> On 25 Mar, 11:59, "vimmi" <vimal.veeren...@gmail.com> wrote:

...

>> The only thing that i know about matched filter is that it performs
>> mathematical convolution function.
>
> No, it doesn't. First of all, read up on DSP.

Don't all signal filters (distinguished from coffee filters) convolve in
time?

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

On 25 Mar, 14:47, Jerry Avins <j...@ieee.org> wrote:
> Rune Allnor wrote:
> > On 25 Mar, 11:59, "vimmi" <vimal.veeren...@gmail.com> wrote:
>
> * *...
>
> >> The only thing that i know about matched filter is that it performs
> >> mathematical convolution function.
>
> > No, it doesn't. First of all, read up on DSP.
>
> Don't all signal filters (distinguished from coffee filters) convolve in
> time?

OK, let's ask from the other direction: If I state a
FIR filter, say,

b = [1 2 3]

or an IIR filter,

a = [1 1.8 0.8]
b = [1 0 1]

I just see lists of numbers. Where are the convolutions?

Rune

On Mar 25, 6:59*am, "vimmi" <vimal.veeren...@gmail.com> wrote:
> To all the members of this community,
> iam doing my project on ultrasonic signal processing.
> i need to design a matched filter,to remove the white noise from the
> received signal(it is the signal received by ultrasonic receiver sensor).
> as iam having very little knowledge about signal processing i dont know
> how to design a matched filter practically for a given frequency around
> 40KLHz.The only thing that i know about matched filter is that it performs
> mathematical convolution function.
> *CAn anybody help me to do that?

What you're looking for is probably a Wiener filter, not a matched
filter. Matched filter is for decoding of a communication signal.

Since they are both a "filter," they are implemented by convolution.

Now, are you looking for help on:
1) Designing a Wiener filter, or
2) Implementing one, given that you have a design, or
3) Both?

To design a Wiener filter, you need to assume that your signal
of interest is stationary, and you need to estimate or derive its
spectrum.

If you do a google search, there are many explanations of
how to do a convolution in software or hardware.

Julius