marp84 Posted October 17, 2008 Report Share Posted October 17, 2008 i've labview 8.0 professional development system can i bulid the notch filter in this software and if it's can how to build it ? do you know what is the lower and higer cut-off frequency of this filter to eliminate the noise from ecg signal? tanx before Quote Link to comment
jgcode Posted October 17, 2008 Report Share Posted October 17, 2008 QUOTE (marp84 @ Oct 16 2008, 08:45 AM) i've labview 8.0 professional development system can i bulid the notch filter in this software and if it's can how to build it ?do you know what is the lower and higer cut-off frequency of this filter to eliminate the noise from ecg signal? tanx before There are filter VI's located in the Signal Processing>>Filters sub-palate that may help you. I have also written custom ones easily enough before as well (e.g. 4th Order Dual Pass Butterworth etc..) Your ECG question is one for a domain expert not a programmer But you may be able to do some regression testing to see what filter cutoff(s) give you the closest signal representation with adequate noise removal. Quote Link to comment
TobyD Posted October 17, 2008 Report Share Posted October 17, 2008 QUOTE (marp84 @ Oct 15 2008, 04:45 PM) i've labview 8.0 professional development system can i bulid the notch filter in this software and if it's can how to build it ?do you know what is the lower and higer cut-off frequency of this filter to eliminate the noise from ecg signal? Have you seen http://zone.ni.com/devzone/cda/tut/p/id/6349' target="_blank">this article? It could be helpful. Quote Link to comment
marp84 Posted October 17, 2008 Author Report Share Posted October 17, 2008 can i build the notch filter with labview 8.0 proffesional development system? do you know what is the lower and higer cut-off frequency of this filter to eliminate the noise from ecg signal?l? Quote Link to comment
TobyD Posted October 17, 2008 Report Share Posted October 17, 2008 QUOTE (marp84 @ Oct 16 2008, 11:12 AM) can i build the notch filter with labview 8.0 proffesional development system?do you know what is the lower and higer cut-off frequency of this filter to eliminate the noise from ecg signal?l? Yes. Search the LabVIEW examples for filter or filtering and you will find many examples. As for frequency, the ecg signal frequency is generally between 0.1 and 250 Hz. The P-wave and T-wave are made up mostly of frequency components below 60 Hz, the R-wave also, but it has other frequency components up to 250 Hz. The problem is that you have many sources of noise that can effect such a weak signal. 60 Hz (or 50Hz depending on where you are) power line noise, low frequency noise caused by breathing or movement of the electrodes, and broader spectrum (1-5000Hz) electromyogram (EMG) noise usually caused general movement of the patient. You will need some extremely clean hardware amplification on the ecg signal (amplification factor of around 500) to be able to successfully filter out the noise with software. The ecg is a common project for students and there are hundreds of sites online with anything you've ever wanted to know about ecg signals (I happen to know because I made one for my junior year project not too many years ago ). -Toby Quote Link to comment
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