Any way to increase the number of frames per second (slow time sampling rate)?

Discussion in 'X2 & X4 SoC' started by yu_rong, Oct 12, 2016.

  1. yu_rong

    yu_rong New Member


    I have a respiration sensor (X2M200). I am using for heart rate detection and wave reconstruction. It seems working.

    Now I am trying to measure the micro-Doppler from the spinning blades of my octocopter (DJI spreading wing 1000).
    The spinning speed is 50 to 100 Hz (non-flying mode). But the Xethru sensors only output 20 frames per second. Does anyone know to improve the slow time sample rate? It is possible. What is the the upper limit?

    Greatly appreciate the help,
  2. Olav Liseth

    Olav Liseth Administrator Staff Member


    Great work!
    It is not possible to change the FPS with the current module, you will have to use the Ancho kit to get full radar functionality. We will provide possibilities in the future.

  3. Josh Gardiner

    Josh Gardiner New Member

    The baseband from the X2M200 respiration sensor is fixed at 20 frames per second, as far as I know there are no options to increase or decrease the down sampled stream. In the Rev.B Preliminary Datasheet for the X2M200 the firmware block diagram show why this is probably the case as the down sampled stream is used for the Breathing Pattern Estimator the Noise Map and the Movement Detector.
    Olav Liseth likes this.
  4. yu_rong

    yu_rong New Member

    Hi Josh:

    Thanks for your reply.
    Glad to get your confirmation.
  5. yu_rong

    yu_rong New Member

    Thanks for the reply. I will check the specs of the Ancho kit.
    The kit is way more expensive than the fundamental one. Is there any useful information you can share with us?
    Let you know if I more questions about kit you are talking about.
  6. yu_rong

    yu_rong New Member

    Hi Olav:

    I just checked the specs of the Ancho kit. The average power is - 13dbm @ 7 GHz. Does it mean at different pulses that it has different average power?

    The specs gives frame offset and window length. How can I get FPS from them? What is the function range of FPS of this kit? We need this parameter because we need to know if this is the right device to go for our research and need to know how flexible it it.

    Thanks for your help.
  7. Will

    Will Moderator XeThru Partner


    Yes, the average output power scales with the Pulse Repetition Frequency (PRF), see attachment from page 8 of the X2 data sheet.

    The Ancho kit FPS is dictated by the radar sweep time (function of desired SNR and PRF), transfer time (function of the SPI clock speed), and the processing overhead (function of CPU speed and algorithm complexity). Depending on your application, the Ancho kit can operate at frame rates from sub-Hz to ~600 Hz. However, at the latter speeds the signal fidelity might not work for your application because of severely low integration time, and this would also be associated with minimal processing.


    Attached Files:

    Olav Liseth likes this.
  8. Nir Regev

    Nir Regev New Member

    hi yu_rong
    Note that if the rotation freq f_r=50 to 100Hz the micro-Doppler side bands will occur in spacing of 2x100Hz, 2 being the number of propeller blades on each propeller. You will probably need a few KHz of BW if you want to the full microDoppler spectrum.
  9. yu_rong

    yu_rong New Member

    Thanks. Olav.
  10. yu_rong

    yu_rong New Member

    Thanks. Will. The problem is solved. We end up using USRP radios to do the experiment and able to get the results.
  11. yu_rong

    yu_rong New Member

    Nir. You are right. Thanks for your reply. The problem is solved. I was using a USRP B210 to get the desired results and the whole Doppler spread is about + 500 Hz.
  12. Nir Regev

    Nir Regev New Member

    hi yu_rong
    would you mind sharing the USRP B210 setup and parameters you used for this task?
    if you want you can email me at