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filtering?

Started by Maryam Amoui December 29, 2006
Hi;
How can we filter 2 signals from eachother.
for example,I have a signal which is the ECG of mother & also baby
toghether,how can I seperate these two from eachother & also ,how can
I separate noise of city voltage?

I will be very glad if someone answers me.

thanks,
maryam
see help filter
----- Original Message ----
From: Maryam Amoui
To: m...
Sent: Thursday, December 28, 2006 12:16:07 PM
Subject: [matlab] filtering?

Hi;
How can we filter 2 signals from eachother.
for example,I have a signal which is the ECG of mother & also baby
toghether,how can I seperate these two from eachother & also ,how can
I separate noise of city voltage?

I will be very glad if someone answers me.

thanks,
maryam








AOA MArium


This problem is known as spectral overlap problem. You need to apply some adaptive filters for separating these signals. say LMS adaptive system. Matlab documentation guides about the implementation of these filters and a good description of narrow band overlap problem is found in Simon Hyken (Adaptive Filter Theory).


Regards


HR






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From: "Maryam Amoui" <maryam_1356@yahoo.com>
To: matlab@yahoogroups.com
Subject: [matlab] filtering?
Date: Thu, 28 Dec 2006 17:16:07 -0000






Hi;
How can we filter 2 signals from eachother.
for example,I have a signal which is the ECG of mother & also baby
toghether,how can I seperate these two from eachother & also ,how can
I separate noise of city voltage?

I will be very glad if someone answers me.

thanks,
maryam











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.

nc3=3

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I believe the 2 ECG signals of mother & baby occupy different band (have different frequency). You could perform FFT on them filter them in frequency domain using band pass filter and then perform IFFT to get back your time signals.

I hope that helps.
Hi;
>How can we filter 2 signals from eachother.
>for example,I have a signal which is the ECG of mother & also baby
>toghether,how can I seperate these two from eachother & also ,how can
>I separate noise of city voltage?
>
>I will be very glad if someone answers me.
>
>thanks,
>maryam
>
ZQ Taha-

> I believe the 2 ECG signals of mother & baby occupy different band (have different frequency). You could perform FFT
> on them filter them in frequency domain using band pass filter and then perform IFFT to get back your time signals.

That won't work; they will overlap in frequency. Linear predictive and adaptive filter techniques would be more
effective. See previous post by Humera Rafique Butt on this subject (31 Dec 2006), about "implementation of these
filters and a good description of narrow band overlap problem is found in Simon Hyken (Adaptive Filter Theory)."

-Jeff

> Hi;
>>How can we filter 2 signals from eachother.
>>for example,I have a signal which is the ECG of mother & also baby
>>toghether,how can I seperate these two from eachother & also ,how can
>>I separate noise of city voltage?
>>
>>I will be very glad if someone answers me.
>>
>>thanks,
>>maryam
Zafar-
> Are you about those signals overlap? Cos the baby's heart beat is about 150 bpm,
> where as normal adults is about 70 bpm. Translated on to time scale the baby's
> heart beat must occupy higher frequency band. Correct me if I am wrong. Thanks

The heart rate is a fundamental frequency, but the waveforms are complex and made up
of many frequency components. Secondary frequencies will overlap.

-Jeff

PS. Please post to the group, not me directly.
> On 1/15/07, Jeff Brower wrote:
>
> ZQ Taha-
>
> > I believe the 2 ECG signals of mother & baby occupy different band
> (have different frequency). You could perform FFT
> > on them filter them in frequency domain using band pass filter and then
> perform IFFT to get back your time signals.
>
> That won't work; they will overlap in frequency. Linear predictive and
> adaptive filter techniques would be more
> effective. See previous post by Humera Rafique Butt on this subject (31
> Dec 2006), about "implementation of these
> filters and a good description of narrow band overlap problem is found in
> Simon Hyken (Adaptive Filter Theory)."
>
> -Jeff
>
> > Hi;
> >>How can we filter 2 signals from eachother.
> >>for example,I have a signal which is the ECG of mother & also baby
> >>toghether,how can I seperate these two from eachother & also ,how can
> >>I separate noise of city voltage?
> >>
> >>I will be very glad if someone answers me.
> >>
> >>thanks,
> >>maryam
>