Finding RMS, Mean and Median Power Frequency of EMG signal

[Jazlan]

Hello to Zhijun Gu and biomedical user group members.

Im currently trying to find the Root Mean Square (RMS), Mean Power Frequency (MNF) and Median Power Frequency (MPF) of one channel of EMG signals measured from my forearm muscles in real time. I constructed a circuit to measure EMG signals and placed an optocoupler (for safety) in between the output of the EMG circuit and input channel of the NI USB-6008 DAQ which I am using. Using an optocoupler is known as galvanic isolation. The purpose of galvanic isolation is to separate the ground of the EMG circuit and the ground on the NI USB-6008. (I did ths under supervision of my professor)

As for the labview part, im following Zhijun Gu's example entitled [NI Days 2009 China Demo] EMG Analysis Using Biomedical Startup Kit which is available in the documents section. On the DAQ Assistant I set both samples to read and rate to 5000:

I have used the following block diagram:

I managed to display EMG signal and power spectrum using waveform graphs however im not getting the correct results for the RMS, MNF and MDF.:

What corrections/suggestions should I do on this VI in order to get correct RMS, MNF and MDF readings?

Thanks!

Jazlan

Labview 2010

[Jazlan]

Here are the attached images of the block diagram and front panel

[Jazlan]

I forgot to mention that in the example entitled: [NI Days 2009 China Demo] EMG Analysis Using Biomedical Startup Kit, the example program finds the RMS, MDF and MNF of an EMG signal stored in tdms file format. Im trying to find the RMS,MDF and MNF from a real time measured EMG signal aquired through NI USB6008 DAQ device..

[ZJ.Gu]

Hi Jazlan,

I am not sure why your x axis is so huge number. I suggest you first save your signal (30sec or 1minute) with muscle contraction to tdms to verify your codes (You could use Biosignal Logger in Biomedical Startup Kit). Then try to see whether it works in real time mode.

You could also attach your tdms file when you have for us to have a look.

Thanks!

ZJ Gu

[ahjun13]

Hi Jazlan,

Im currently working on similar project like your figure above. Would like to ask, did u manage to get MPF in real time?? I tried the example block diagram in labview on my project but i din manage to get the MPF. Furthermore, i save my data in csv instead of tdms. Should i compute the MPF blocks outside the loop?

Thanks.

[Ramon Campos]

Hello,

i've "fought" to implement some MPF and MNF analysis in my Master degree.

Unfortunaly, MPF and MNF vi in biomedical toolkit didn't worked for me.... it was needed to use "advanced signal processing" toolkit and some implementation. RMS vi is in biomedical is ok.

May this help a little. Take a look at:

https://decibel.ni.com/content/message/28056#28056

Good research!