IWR6843AOPEVM: Having exported .dat file from Demo Visualizer, how do I parse the range for range profile 0th doppler

Hi Marius,

The points represent the sum of log2 magnitudes of received antennas expressed in Q9 format. Details on the output format can be found here: link. 

I am going to get back to you on how to best build a doppler plot with this information within 2 days.

Thank you,

Angie

Ok. Thank you. I am looking forward to your answer. In addition: What are the values for range FFT size and doppler FFT size for IWR6843AOPEVM? Can you help me here as well?

In addition, I have problems reading the file as it does not seem to add up to a multiple of 32 bit. It does some padding to get to a 32 bit multiply, but afterwards it cannot find the magic words until a lot of bit ran through. The program seems to only read every second package. Do you have an idea?

Hi Marius,

The TLV packet of information will send the packet type and then the packet length and then the information for that packet (i.e. the range profile packet should send the type (MMWDEMO_OUTPUT_MSG_RANGE_PROFILE) then the length (Range FFT size) x (size of uint16_t) then the 0th doppler array of profile points. 

More information can be found at the doxygen for the sdk (this information may help you debug this issue!) here file:///C:/<SDK_DOWNLOAD_LOCATION>/mmwave_sdk_03_05_00_04/packages/ti/demo/xwr68xx/mmw/docs/doxygen/html/index.html#output

I am continuing to look deep into this question as well.

Thank you,

Angie Mitchell

Hi Marius,

One follow up question, why do you need to build the plot yourself instead of using the plot that is in the demo visualizer?

Thank you,

Angie

Hi Angie,

I would like to save and compare the data. Furthermore I need an x/y plot and not a 3D scatter plot. Do you know how to get the range for the range/noise profile for the plot?

Thanks,

Marius

Hi Marius,

I believe the x data can by found by range bin idx * the range resolution. 

Thank you,

Angie

What do you mean exactly? What is the range bin idx and where do I get it? It isn't sent, is it? https://dev.ti.com/tirex/explore/node?a=VLyFKFf__4.11.0&node=AH-2SVYArR7wfP9cuNOm0w__VLyFKFf__4.11.0

Thanks,

Marius

Hi Angie,

thank you very much. This clears up a lot. But I still don't get, how do I calculate the actual range in meters from numRangeBin (TLV length), so that I can plot noise or range profile on y-axis and range in meters on x-axis as the demo visualizer does?

Thank you or you dedicated support!

Marius

Hi Marius,

The range bin size is determined by the range resolution (in m). So this is where you would multiple the bin index by the resolution to get the distance of that range bin.

Thank you,

Angie

Hi Angie,

thanks again. Got it. Regarding getting the Range data. What is my range FFT size? How do I find it out?

Thanks,

Marius

Hi Marius,

The range profile TLV first sends the type and then the length. The length is 2 Bytes x Range FFT size.

Thank you,

Angie