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DCA1000EVM: Packet reorder and zero fill utility effect?

John Booth
Intellectual 490 points
Part Number: DCA1000EVM

Hi,

This question relates to the Packet_Reorder_Zerofill.exe as described in the mmwave studio user guide.

I can understand the importance of reordering the UDP data but what impact does zero filling have on the post processing? Is it just used as an indicator to say ignore this data or are the FFTs actually computed on ADC samples that have been set to zero (there are numerous chirps worth of data missing so I believe it will have a big impact)?

If the zero'd data is ignored how is the radar data cube being formed - are samples taken from future frames (e.g. the next loop of TX+RX chirps).

Thanks

  • 0
    TI__Genius 11405 points
    Hi,

    I'll take this question to our expert and let you know.

    Regards,
    Michelle
  • 0
    TI__Genius 11405 points
    Hi John,

    The reason to use zero padding is to make sure the received data is in correct sequence. WHen the user gets a stream of bytes on the PC. How does he know which data corresponds to which chirp and frame ? The only way to know that is by counting the number of bytes since the user knows how many bytes he has configured in each chirp and frame. So if any data gets missed then this whole count will get shifted and that will cause data to be wrongly assumed in a different chirp and data between chirps can get mixed etc. so the zeros are padded to make sure the correctly received data is put in the correct location.

    Hope this helps.

    THanks and Regards,
    Michelle
  • 0 in reply to Michelle Liu
    Intellectual 490 points
    Hi Michelle,

    Does that not lead to a useless datacube being produced? If multiple chirps are just replaced with zeros and if this happens most frames then it becomes unusable.

    Does the post processing routine that ti have really accept that? It doesn't try to reorder with chirps from future frames?

    Best regards,
    Richard
  • 0 in reply to John Booth
    TI__Genius 11405 points
    That would depend on the PC used and the windows applications running etc

    Regards,
    Michelle