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ads1293 for EMG

Haechang Jung
Prodigy 20 points

Other Parts Discussed in Thread: ADS1293EVM, ADS1293

Hi,

I am using ads1293EVM these days. It is for ECG but I want get information about EMG.

What I am wondering is that if i can get signals for EMG with ads1293EVM.

If so, how can I do that? Please help me to find this solution.

Thank you.

  • 0
    TI__Expert 3835 points

    Hello,

    EMG was not explored when the ADS1293 was released, but from what read in the E2E forum, it shares some similarities with ECG. What are the characteristics of the signal you expect to get from the sensors, like minimum amplitude, maximum amplitude, bandwidth? The bandwidth and sampling rate of the ADS1293 are configurable, but the AFE gain is fixed.

    Regards,

    Sergio

  • 0 in reply to Sergio
    Prodigy 20 points

    Thanks for reply.

    I'm gald to know bandwidth and sampling rate are configurable.

    I want to get maximum amplitude of signals from 8Hz to 500Hz in bandwidth.

    The bandwidth of ECG is 0.05~100Hz, and the bandwidth of EMG is 8~500Hz.

    I can find the following comments in Functional description part in data sheet :

    Each of the three channels is synchronized and provides digital filtering with a cut-off frequency that is programmable from 5Hz to 1280Hz. Each channel filter can be set independently while maintaining synchronization. 

    How can I configure digital filtering on ads1293? If there is an example related to this, please let me know.

    According to Table 6 in datasheet, If I set such like that R1=2, R2=5 and R3=3 for ECG channel, BW is 510Hz.

    so, Can I get signals similar with EMG If I set such like that?

     

  • 0 in reply to Haechang Jung
    TI__Expert 3835 points

    Good, you identified one combination of filter settings that gives you an adequate bandwidth (510Hz). You have a typo, R3=4.

    There is another combination in Table 7 for a bandwidth of 520Hz (R1=4, R2=5, R3=4). For this configuration the SDM should be configured to a sampling rate of 204.8kHz... this is done in register 0x13. The RMS noise is lower in this configuration because the SDM is sampling at twice the speed.

    For the EMG bandwidth in question, do you require a high-pass filter? The filters in the ADS1293 are only low-pass filters.

    There are some examples on how to configure the chip for different ECG applications starting from page 39 of the datasheet, but your application should be slightly different. I hope you can still use these examples as a starting point. If you have a diagram of the system that you need and can't find how to configure the chip I can take a look at the diagram and point you to the appropriate registers.

    Regards