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ECG device

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by Zener_Diode, Mar 13, 2007.

  1. ccurtis

    ccurtis Active Member

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    Thanks! Okay. When you get the ECG signal recorded would you please post that? Please?

    Most modern digital oscilloscopes provide a means to record the trace. I have seen this as a 3.5 floppy drive, and mostly now, USB for a thumb drive.
     
    Last edited: Mar 17, 2009
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

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  3. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    hi bro, do you know about and what's Noise Cancellation?
    do you know how to make it?anybody have the circuits?cause really needed to remove the noise from our body, just i know our body is like antenna so our body receive all frequency arround us.i know this can mess up the signal of heart beat that i use to make ecg circuit.
    if anybody know abut the niose cancellation for ecg circuit please share it with me.
    tanx before
     
  4. dave

    Dave New Member

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  5. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Two seconds ago I answered exactly this same question in your PM to me.

    The common-mode signal (DC and mains pickup by the body) from the instrumentation amp is filtered and inverted then fed to the patient's right leg to cancel the common-mode signals.
     
  6. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    so i don't need the Noise Cancellation?
     
  7. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Why not make the ECG circuit that is shown on the datasheets for intrumentational amplifier ICs?
     
  8. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    how about adaptife noise cancellation?
     
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Maybe you mean, "adaptive"? ECG circuits use the common-mode cancellation opamp.
     
  10. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    so how i can make the common-mode cancellation opamp?
     
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It was posted before. It takes the common-mode DC and low frequency AC from the instrumentation amp and feeds the patient's right leg like opamps A1 and A2 in this ECG circuit taken from the datasheet of an instrumentation amp:
     

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  12. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    how i can make the common-mode cancellation opamp in my circuit (see attachment)?
     

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  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You are going around in circles.
    Yesterday I posted an ECG circuit that shows an opamp making the common-mode cancellation signal. The circuit was posted twice in this thread.
    Today I copied the ECG circuit from that datasheet of the AD620 intrumentation amp that you are using. It is here:

    Don't you look at the datasheets of parts that you use?????
     

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  14. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    do you know about isolation power supply?
    can you tell me waht is all about?
     
  15. blueroomelectronics

    blueroomelectronics Well-Known Member

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    It's a set of 3V batteries in the schematic.
     
  16. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    why my circuit still have a noise that is sinus signal so the heart beat signal cant be viewing? please help me to remove this noise?
    tanx
     

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  17. audioguru

    audioguru Well-Known Member Most Helpful Member

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    As you have already been told, your simple circuit is missing the common-mode cancellation circuit that feeds the right leg of the patient instead of your ground wire.
    The datasheet for the AD620 instrumentation amp shows it in their recommended ECG circuit.
     
  18. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    i can't find AD705J so what i must to do to change it?
    how i built th ehigh pass filter with frequency 0.03Hz?
    then for the output amplifier use G= 143?
    tanx
     
    Last edited: May 17, 2009
  19. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Simply look at the spec's of the AD705J opamp in its datasheet and find another similar opamp:
    1) It has an extremely low input offset voltage and input offset current.
    2) It has very low input current and a very high input impedance.

    It is simple to make a highpass filter with a frequency of 0.03Hz.

    It is simple to make an amplifier with a gain of 143.
     
  20. ranggaperdana_06114

    ranggaperdana_06114 New Member

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    what ic i must use to make G=143
     
  21. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You should learn about opamps.
     

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