Negative SNR

[Hami45]

hello all

i have a problem

i have a ECG signal that it's without noise . but when i want to measure SNR ( signal to noise ratio ) i see negative number like -5 or -6 ........

a negative number for snr mean which noise signal is greater than ECG signal but my signal is without noise .

please help me

i attached my file

[johnsold]

I do not have the SVT VIs.

Are some of the high frequency components of the ECG waveform being included in the noise part of the calculation? 

Lynn

[Hami45]

i don't know exactly

i sent another circuit for SNR calculation .

the result of  both of them are the same

[johnsold]

I do not have some of the subVIs for the Simulate ECG VI. Please create an indicator on the output of Simulate ECG.vi. Run the VI. Then Edit >> Make Current Values Default. Save the VI again. Post that VI.  It will have the data in the indicator and then I can look at what is going on.

Lynn

[altenbach]

All this seems to be part of the biomedical toolkit. I don't have it either.

[Hami45]

i done

[billko]

Wish I could open the VI.  😞  You sure you haven't swapped signal and noise in your calucaltion?

[JÞB]

You probably did not want the reciprical of a logrithmic ratio  that just doesn't wook too well