How to inteprate the X4M05 data

Discussion in 'X4M03' started by Ziqi Wang, Nov 1, 2019.

  1. Ziqi Wang

    Ziqi Wang New Member

    Hi,
    Thanks for your attention. I am using the X4M05 sensor connected to Raspberry Pi for data collection and I enabled the downconversion. The data within a frame I printed out look like the following.

    [0.017301, 0.009329, 0.006502, 0.007107, 0.006092, 0.004720, 0.002685, 0.000522, -0.000329, -0.001065, -0.001485, -0.001143, 0.000503, 0.002794, 0.003689, 0.002636, 0.001316, 0.001197, 0.001325, 0.001204, 0.001242, 0.001270, 0.000914, 0.000516, 0.000373, 0.000525, 0.000708, 0.000651, 0.000395, 0.000169, 0.000079, 0.000134, 0.000120, -0.000001, -0.000024, 0.000002, 0.000010, -0.000071, -0.000070, 0.000111, 0.000187, 0.000199, 0.000176, 0.000068, 0.000026, -0.000050, -0.000092, -0.000172, -0.000102, 0.000064, 0.027536, -0.003466, -0.010125, -0.003319, 0.001160, -0.000582, -0.002957, -0.002698, -0.002378, -0.002557, -0.003323, -0.005962, -0.007927, -0.006136, -0.003172, -0.001246, -0.000146, 0.000375, 0.000752, 0.000923, 0.000536, 0.000020, -0.000078, 0.000048, 0.000069, 0.000032, -0.000055, -0.000342, -0.000455, -0.000184, 0.000056, 0.000051, -0.000018, -0.000021, 0.000107, 0.000182, 0.000037, -0.000125, 0.000031, 0.000236, 0.000239, 0.000127, 0.000043, 0.000076, 0.000108, 0.000051, -0.000045, -0.000077, -0.000070, 0.000007]

    I wonder how can I know the sampling frequency (or time interval between adjacent data points)?

    Also, I wonder what is the highest frame rate allowed in X4M05, suppose Pulse-per-step and iterations, etc are changed accordingly? e.g. Is there any chance for me to raise the sampling frequency to 1kHz?

    Many thanks for any help!
     
  2. Allen Wu

    Allen Wu Moderator Staff Member

    Hi Ziqi,

    Sorry for the late reply. First about the data within a frame:

    One RF frame consists of 1536 bins / datapoints according to X4 datasheet.

    Given Sampling frequency, Fs=23.328GHz, LightSpeed = 299792458
    rf_interval = LightSpeed/23.328e9/2 = 0.0064255928069272975
    Frame lenghth: (1536-1)*rf_interval= 9.863284958633402

    The downconversion process uses decimation factor 8 with a 4 bins delay, you get 2.916 GS/s sampling rate and 1536/8-4= 188 bins baseband data.
    bb_interval = LightSpeed/2.916e9/2 = 0.05140474245541838
    Frame length: (188-1)*bb_interval = 9.61268684

    So, for baseband data, the distance between 2 points (bins) is bb_interval: 0.0514 meters

    Allen
     
    Last edited: Nov 5, 2019
  3. Allen Wu

    Allen Wu Moderator Staff Member

    Hi Ziqi,

    As for the 2nd part about setting FPS to 1kHz, it is possible.

    You may like to first look at XeThru X4 Radar User Guide:
    https://www.xethru.com/community/resources/xethru-x4-radar-user-guide.149/
    Chapter 3.3 Calculating Maximum Frames Per Second, there is an equation on how to calculate Frames Per Seconds.

    Discussion on this thread and X4 guide could be good references:
    https://www.xethru.com/community/threads/how-can-i-get-a-high-frame-rate-more-than-400.204/

    Code Example:
    Latest ModuleConnector python example on how to change X4 configuration.
    https://github.com/xethru/XeThru_Mo..._record_playback_radar_raw_data_message_2D.py

    Allen
     
    Charlie Shao likes this.