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ADS1294R Support required

Other Parts Discussed in Thread: ADS1294R, CC2541, ADS1294

Hi Sir  / Madam ,

This ia vengad here from Avnet , One of my customer is trying to implement ECG Application based on ADS1294R . customer is doing  the testing in proto  board  ( Respiration mode (internal) set ON ) . Input signal is fed from PS420 (Fluke Simulator).   They are getting  ECG output from CH2, CH3 and CH4 with some 50Hz noise on baseline . In CH1 (Respiration out), They got output with lot of noise.  They are not able to make out clear envelope of Respiration signal.  The input components to ADS1294R, used  are with values same as given in the data sheet. They have also  tried with different setting (Modulating frequency, Channel Gain, Phase) and we could get similar outputs with noise.

Please do find some more input from customer :

  1. output data from other ch2 to ch4 gives ECG shaped waveforms when plotted.
  2. Respiration out is there with noise as well as doesn’t represent the input.
  3. when they have studied the captured data, for particular gain, the MSB byte is maintaining the same value for all samples. The MSB byte changes to another same value for different gain. The MSB byte value doesn’t seem to be proportional with gain. Also as the MSB byte is constant value, does it add any significance in decoding?
    Is the respiration data format is different from other channels?
    Please arrange to get the decoding format for the Respiration data out and for other channels.
  4. Data captured with 3 different gains are attached for reference. Input signal is – ECG-60BPM, Respiration – 30RPM, Baseline – 1000 Ohms, Delta R – 3 Ohms. The input is fed from Fluke Simulator PS420. Register setting : Modulating frequency – 64KHz, Phase – 135o .

Regards/

vengad

 

  • Hi ,

     

    Any update on above post .

    Rgds/

    vengad.

  • Hello TI-Team,

    I also have the problem of high 50Hz impact on the Signals in my design.

    I am using an ADS1294 combined with a CC2541 for wireless application.

    I already try to use an digital bandpass for the 50 Hz, but i would actually know what the problem could be.

    The System is battery powered, meaning the 50 Hz is coming from the PC, measurement equipment and all the stuff running in my room.

    Have you some hints what normally could be the problem and what would maybe help.

    Regards

    Melanie

  • Hi Melanie,

    All of the sources that you mentioned could actually be introducing the noise issue in your system. Most customers typically implement a very steep notch filter at 50Hz/60Hz in their firmware to cut this out.

    What Data Rate do you require for your application? If you could run the ADS1294 in Low-Power Mode at 125SPS, your -3dB bandwidth in the digital filter would only be about 32Hz.

    Best Regards,