ECG Circuit

Discussion in 'The Projects Forum' started by rmmowdhgalya, Jun 27, 2007.

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  1. rmmowdhgalya

    Thread Starter New Member

    May 16, 2007
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    hello.. i have designed an ECG signal conditioning circuit which I have attached... I would like your suggestions on the circuit... it is a three lead ECG circuit.. The ECG signal is generated by a cardiac simulator.. the circuit is only for signal conditioning... The output of my circuit has only noise... Please do help...Kindly let me know as to where i have gone wrong.... i have to submit this in another week.. If there is a 3 lead ECG circuit already available please do send me the link... i will be very grateful..
     
    Ali Emre Yurdagül likes this.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Your zip gives me a file with a .DSN extension. Another graphics format would be better, like .BMP or .JPG.
     
  3. rmmowdhgalya

    Thread Starter New Member

    May 16, 2007
    9
    1
    hello.. i have designed an ECG signal conditioning circuit which I have attached... I would like your suggestions on the circuit... it is a three lead ECG circuit.. The ECG signal is generated by a cardiac simulator.. the circuit is only for signal conditioning... The output of my circuit has only noise... Please do help...Kindly let me know as to where i have gone wrong.... i have to submit this in another week.. If there is a 3 lead ECG circuit already available please do send me the link... i will be very grateful..
     
  4. rmmowdhgalya

    Thread Starter New Member

    May 16, 2007
    9
    1
    Hi iv put up a schematic of my ECG circuit.. would like ur suggestions on it... If there is a ECg circuit already available please do send me the link...
    thanks in advance...
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
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    The bottom part of your schematic seems to be missing.
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    Either that, or the circuit is very strange, indeed. All those instrument amps for two signals?
     
  7. Distort10n

    Active Member

    Dec 25, 2006
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    Here are a few questions:

    1) Why are you buffering a voltage off of the gain setting resistor from the INA114 with the OPA2131? Right leg driver? But I think that is usually from the output of the INA back to the patient.

    2) You are leaving one channel of the OPA2277 floating. If you are not going to use this channel, you should place it in a voltage follower configuration using a zero ohm feedback resistor, and an open gain setting resistor. That way if you ever want to use the second channel, you already have pads for the resistors.

    3) What are your general concerns?
     
  8. rmmowdhgalya

    Thread Starter New Member

    May 16, 2007
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    1. I got details of the right leg driver part of the circuit from a book on Biomedical Instrumentation by Joseph J Carr and I also saw it in the datasheet of Ina 114.
    2. My concern is that im not getting the required ECG output and the frequency of my output signal is around 50Hz which I feel is the power line interference. And the output is mainly noise.

    Thank you
     
  9. Distort10n

    Active Member

    Dec 25, 2006
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    Yowza, so it is. I am guessing it serves to keep the shield at a reference potential within the common-mode range of the INA114. This is something I will have to dig deeper into myself.

    THe INA114 has good CMRR at 50/60 Hz, so you should be good there. Olimex (?) creates boards for the Open EEG project. That might be a good place to go and see if there is any extra filtering on the inputs.
     
  10. semsem11

    New Member

    Nov 17, 2008
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    thaaaaaaaaaaaaaaaaaaaaaaaaaaaaaanks
     
  11. amiyasar

    New Member

    Nov 27, 2008
    1
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    My experience with ECG is quite painful. What I get is only hum. I used TL084 and TL082 ICs, an optional filter with jumper options and computer scope software from C Zeitnitz. Did not use Optocoupler. In the schematic, asterix represent test points. The 2(two) 22k resistors were meant to act as load resistance for the filter.
    Can I use center zero voltmeter to bypass the computer hum? Electronics geeks Please advice. Thanks[​IMG]
     
  12. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    I have an ECG simulator circuit that a friend built many years ago. I have attached the circuit and examples of the output waveforms. A bit dated technology, but it worked. Now he would probably use a PIC with a look-up table and a filtered PWM output.

    Sorry about the size, but I needed to retain detail.

    Credit goes to John Kruse, Minneapolis VA

    Oops! Thought I was posting to: http://forum.allaboutcircuits.com/showthread.php?t=28854

    Ken
     
    Last edited: Oct 16, 2009
  13. nozone

    New Member

    Oct 18, 2009
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    simple and good
     
    Last edited: Dec 19, 2009
  14. Audioguru

    New Member

    Dec 20, 2007
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    This is similar to your circuit. It is easy to see because it uses opamp symbols intead of the boxes used in your schematic. It has matched resistors for good common-mode noise cancellation.
     
  15. Azzy

    New Member

    Oct 9, 2010
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    hi, have you come up with a final circuit for ECG simulator?? I need help
     
  16. beenthere

    Retired Moderator

    Apr 20, 2004
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