Radar pulse shape

Discussion in 'X4M03' started by Simen, Jan 15, 2018.

  1. Simen

    Simen New Member

    Hi,

    We are trying to simulate the radar system X4M03 in an EM simulator. We need to know the shape of the emitted radar pulse to get accurate simulations. Is it possible to get a plot and/or some data that describes the pulse of radar system?

    Simen Husøy
     
  2. xiaopeng

    xiaopeng New Member

    waiting for the answer
     
  3. Olav Liseth

    Olav Liseth Administrator Staff Member

    Hi Simen,

    I am not sure what you want to simulate, but the TX bandwidth and center frequency given in the data sheet is often enough. The chip generated pulse will be changed by the channel, e.g. transmission lines, antennas and reflections/clutter.

    See this post for an example on how to estimate a pulse in python: https://www.xethru.com/community/threads/x2m200-sampling-rate.187/#post-835

    Another possibility is to use the module to sample a pulse, either a reflection or the direct coupled energy from TX to RX antenna.

    Olav
     
    NSANGOU CHOUAIBOU likes this.
  4. Simen

    Simen New Member

    Do you have a measured signal after it has passer through the transmission line and antenna?
    Simen
     
  5. Shihab Khan

    Shihab Khan New Member

    Hi Olav,
    I'm trying to use the X4M03 to monitor respiration and heart rates. Can you tell me how to read the raw reflected signal from the module onto a variable in Matlab? In the example XEP_X4_plot_frame.m, does the values in the variable 'frame' indicate the raw signal reflected from the body and other objects? Also, what is the sampling frequency? I need to use it for frequency response analysis.

    Thank you
     
    Faisel Tubbal likes this.
  6. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Simen,
    After Rx antenna, you can't get unique pulse shape as your signal is a sum of multiple delayed versions pulses of your emitted unique pulse. Your received waveform is then function of the propagation through the channel, lines, antenna etc..
    It is helpless to look for an ideal pulse shape after lines and antenna as all depends on your final application and propagation environment.

    B.R
     
    Olav Liseth likes this.
  7. Simen

    Simen New Member

    I understand, thanks for the reply.
     
  8. Faisel Tubbal

    Faisel Tubbal New Member

    Hi NSANGOU,
    Is it possible to obtain the breathing rate from this reflected signal by developing an algorithm on PC to process this signal and hence obtain breathing and heart rate.
    Regards
    Faisel
     
  9. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Faisel,
    Novelda team has turnkey solution for respiration rate, breathing pattern and movement with X4M200 module sensor. If you have good knowlegde on Digital Signal Processing, you can retrieve baseband radar raw data from their sensor and make what you want keeping in mind that all information about the sensor can be find in the datasheet and some examples in modules connectors. The heart rate measurements is also possible with the sensor and it is a matter of signal processing. For custom development, X4M03 development kit can help. Novelda gives the choice between already made solutions based on X4M200 and custom solutions based on X4M03 kit.
    Finally, yes you can use X4M03 with embadded XEP and your custom signal processing or the X4M200 module to do the job.
    X4M200 = Gives respiration and breathing signal from a person with XEP. You can also retrieve baseband raw data including Range-Doppler data with Xethru Explorer or modules connectors and perform DSP on your PC. You can't get access to Novelda embedded code in the sensor
    X4M03 = Embedded XEP, you can retrieve baseband raw data (down converted and decimated reflected RF signal), write your custom algorithm to measure breathing, distance, respiration or heart rate and store your code on the sensor MCU. If the tests are ok, you will have a complete custom working sensor, the same as X4M200 or better according to what you have implemented.

    B.R
    Chouaibou.
     
    Last edited: Jan 29, 2018
    Bjørn Åge Brandal likes this.
  10. Olav Liseth

    Olav Liseth Administrator Staff Member

    Hi,

    I wrote a script sampling the direct path and generates a similar pulse from a sine and a Gaussian envelope, here is the result:
    xep_sample_direct_path.png
    Script is attached.

    * Update 2018-02-01: Removed pylab dependency.
    Olav
     

    Attached Files:

    Last edited: Feb 1, 2018
  11. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Olav,
    Thank you for the script to sample and plot pulses both in time domain and frequency domain.

    B.R
    Chouaibou.
     
    Jagath Gamage likes this.
  12. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Olav,
    The sampled pulse doesn't matched the interpolated pulse. The frame gives sometimes single direct pulse, sometimes multiples direct pulses for frame setting = 1. In addition, I can't get PSD plot, problem with " pylab import * " ?.
    B;R,
    Chouaibou
     

    Attached Files:

  13. Olav Liseth

    Olav Liseth Administrator Staff Member

    Hi NSANGOU,

    I just updated the script from using pylab to using more explicit imports. Make sure you have the right dependencies installed.

    The pulse you have sampled does not look good, are you using latest FW and pymoduleconnector? Which module do you use?

    Olav
     
  14. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Olav,
    I used X4M300 module with the latest module connector (1.4.3) but with SW version 2.5.0, not 2.6.0

    B.R
     
    Last edited: Feb 1, 2018
  15. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Hi Olav,
    It was module FW upgrade problem. I have just made module FW upgrade to 1.4.7. It works great even without explicit imports. Why module with old FW can't sample one pulse per frame ? Why the module with old FW generate a dirac like pulses, but with the latest FW we have a gaussian modulated sine wave ?
    Thank you.

    B.R
    Chouaibou.
     

    Attached Files:

    Last edited: Feb 1, 2018
  16. Olav Liseth

    Olav Liseth Administrator Staff Member

  17. NSANGOU CHOUAIBOU

    NSANGOU CHOUAIBOU Active Member

    Many thanks Olav for your reply.

    B.R,
    Chouaibou.
     
  18. Faisel Tubbal

    Faisel Tubbal New Member

    Thanks a lot Nasngou for your reply. It is very helpful.
    Regards
     
    Olav Liseth likes this.
  19. LauriBuell

    LauriBuell New Member

    As suggested the TX bandwidth and center frequency given in the data sheet is often enough. The chip generated pulse will be changed by the channel.
    Also to use the module to sample a pulse, either a reflection or the direct coupled energy from TX to RX antenna.

    smt pcba
     
    Last edited: Nov 7, 2018