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Different ECG signal from female and male!

Other Parts Discussed in Thread: LMC662

Hi,

I am working on ECG, I designed some circuits and finally I could receive clear ECG signals, but I have an unknown problem, when I finished my tests on my self every thing was ok, but when I tried to get signal from female output signal was extremely low!! In cases that chest lead quality is not good it doesn’t have any problem on men, even in worth case it just could be a bit noisy, but women does not have any signal output. So I think the reason is skin impedance so is it true? How I can solve it that it work for women as good as men.

Any help would be greatly appreciated,

All the best,

Siyasvash.

  • Hello Siyavash,

    Glad to hear you have your ECG circuit working!

    Though I'm not an ECG expert, we have observed a wide variance in quality of signals from all people regardless of sex, age, nationality, etc. I believe this is due to a variety of reasons including skin impedance, motion artifacts, lead placement, quality of body connection, etc. Given that her signal was 'low', perhaps try increasing the gain of the circuit. You could also try moving and/or replacing the leads and taking data from different females.

    I hope this helps.
  • Hi Pete Semig, thank you for your reply,

    the reason of my delay for new post is that I designed new board and I tried to correct any fault in last circuit, in new circuit signals are better but main problem doesn't solved. I know ECG signal are vary from person to person but in some case (all of them are female but not all females) signal is very very low about 1/50 of normal signal. 

    as I read in reference and books, I think key factor is skin impedance, women have more fat under skin so they have higher skin impedance, in this case input current bias of preamplifier is very very important and also CMRR of INA, so I used TI ultra low current bias LMC662 as input buffer. I think it is very good choice but I don't know what is wrong with my design.

    if it is possible give me an email address to send total schematic of Analog part,

    any help would be greatly appreciated,

    Siyavash

  • Hello Siyavash,

    I have sent you a friend request. Please accept so you can share your schematic with me directly.
  • Hi Pete Semig,

    I sent you.

    Best regards,

    Siyavash