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ADS 1198/1298 for stress ECG

Carlos Pais
Prodigy 40 points
Other Parts Discussed in Thread: ADS1198, INA122, ADS1298

we have problems to get good Stress ECG signal with ADS1198/1298. Diagnostic ECG signal records are fine, but ECG in stress has excesive fast baseline wander. Does anyone know what do we have to do to get good stress ECG signal records?

  • 0
    TI__Mastermind 49956 points
    Hi Carlos,

    I've moved this post from the Medical Forum to the Precision Data Converter Forum, where the ADS1x98 is supported. I'm sure you'll find an answer here.
  • 0
    TI__Mastermind 38745 points
    Hey Carlos,

    It is common for the ECG baseline to wander due to patient movement. In fact, system designers develop complex active electronics and/or digital algorithms to remove the baseline wander. Hopefully a community member will be able to provide some insight into any existing or common designs for removing motion artifacts.

    Regards,
    Brian
  • 0 in reply to Brian Pisani
    Prodigy 40 points

    Thanks Brian!

    we have been trying different digital algorithms alternatives but it seems like the ADS has some problem with baseline wander because normally this kind of fluctuations dont get into the ECG bandwidth. Probably, we are omitting an analog circuitry prior of the ADS. Is there any recommendation?

  • 0 in reply to Carlos Pais
    TI__Mastermind 38745 points
    Hey Carlos,

    Such things are typically proprietary for many system designers :-). Perhaps there is something in a medical journal or trade publication about this.

    Regards,
    Brian Pisani
  • 0 in reply to Brian Pisani
    Prodigy 40 points

    Thanks Brian!

    We´ve been working with INA122 for some years and we have implemented a lot of those digital algorithms with very good results (we have published some of them, also), but it seems like the ADS1298 does not work well with stress ECG, unless there is something else that we dont know or find in your white papers...

    Do you know if is there any application datasheet for stress ECG?

  • 0 in reply to Carlos Pais
    TI__Mastermind 38745 points
    Hello Carlos,

    Unfortunately no such documentation exists.

    However, I'd like to try and think through this issue. If you are able to do stress ECG using the INA122, then there must be some difference in the analog front end portion of the circuit. Both chips have front ends with very high input impedance. Could you perhaps point me to some differences between the two designs? Are you using a RL drive amplifier in both designs? Are the electrodes the same? If you are able to share a schematic I would be happy to take a look.

    Brian Pisani
  • 0 in reply to Brian Pisani
    Prodigy 40 points

    I attach below our work paper schematic of a part of the device that uses ADS1298 and the instrumentation made with INA122 that has no problems whith stress ECG. As you can see there, we work with active Right Leg in the ADS1298 design, whereas in the INA122 design we have passive Right Leg. The electrodes are the same (3M).

    Any help will be wellcome!

    Carlos

  • 0 in reply to Carlos Pais
    TI__Mastermind 38745 points
    Hey Carlos,

    Interesting note about the RLD. Can you tell me your settings in the CONFIG3 and RLD_SENSP/N registers?

    Brian