BGT60TR13c ifxdaq radar timestamp issue

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ZINCSNOW
Level 1
Level 1
10 sign-ins 5 sign-ins First question asked

I am using a DAQ recorder to record the radar data from DEMO BGT60TR13C  board. While configuring the system, I made an adjustment to the config parameter frame_repetition_time_s from 30ms to 10ms. However, I noticed that there were instances of repeated timestamps in the radar data. I'm wondering if there are any specific limitations or constraints related to the radar configuration that might be causing this issue. I attached the pictures  of the radar timestamp and config 

 

radar-timestamp.png

config.png

  

 

DEMO BGT60TR13C 

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1 Solution
Siddharth_H
Moderator
Moderator
Moderator
100 solutions authored 50 likes received First question asked

Hey @ZINCSNOW ,

This is a known limitation of the tool as the timestamps are taken from the host (PC) since the sensor has no clock built-in. The main reasons for this are,

1) Due to Limited accuracy of the PC clock and as the data packages are transmitted via USB, which has some buffering capabilities on OS level.
2) We take the PC's timestamp, whenever a frame arrives. Due to buffering, sometimes multiple frames arrive very short after each other. Combined with the limited accuracy of the PC clock, this leads to duplicate timestamps.

However, physically the radar frames have the right timing, it's just the way we record the timestamps.

Thank you,

Siddharth.

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5 Replies
Siddharth_H
Moderator
Moderator
Moderator
100 solutions authored 50 likes received First question asked

Hey @ZINCSNOW ,

This is a known limitation of the tool as the timestamps are taken from the host (PC) since the sensor has no clock built-in. The main reasons for this are,

1) Due to Limited accuracy of the PC clock and as the data packages are transmitted via USB, which has some buffering capabilities on OS level.
2) We take the PC's timestamp, whenever a frame arrives. Due to buffering, sometimes multiple frames arrive very short after each other. Combined with the limited accuracy of the PC clock, this leads to duplicate timestamps.

However, physically the radar frames have the right timing, it's just the way we record the timestamps.

Thank you,

Siddharth.

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Thank you for your explanation. I have updated the ifxdaq to version 4.0.0. However, after tuning the frame rate to 1000 Hz, I observed that the time difference between some consecutive groups of duplicate timestamps remains at approximately 1ms. Is this behavior considered normal, or should the difference ideally be greater than 1ms?

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Montassar-BR
Employee
Employee
5 questions asked 250 sign-ins 25 likes received

Hi @ZINCSNOW,

Which ifxdaq version are you using?
This frame duplication issue at high frame rate recording is fixed with ifxdaq 4.0.0, part of the RDK v3.5 release.

Cheers,
Montassar.

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I was using the ifxdaq 3.2.1. I have updated the ifxdaq to version 4.0.0, and this timestamp issue has some improvement. But when I increased the sampling rate to 200 Hz even higher, the issue still existed. 

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Siddharth_H
Moderator
Moderator
Moderator
100 solutions authored 50 likes received First question asked

Hello @ZINCSNOW ,

Looks like we gotta live with this issue for now until. This is mainly due to the usage of PC timestamp and it's accuracy. We hope to get this fixed in the coming updates. 

Also, can you let me know your use-case on why you are increasing the sampling rate?

Thank you,

Siddharth.

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