MR60BHA2 breath rate consistently shows +4 BPM offset

Products & Technology
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Hello everyone,

I am currently using the MR60BHA2 radar to test respiratory rate. The subject breathes at a fixed pace following a metronome.

However, I found that the radar output breath rate is consistently 4 bpm higher than the subject’s actual breathing rate.

For example:

  • When the metronome is set to 15 bpm, the radar output is stably around 19 bpm

  • When the metronome is set to 20 bpm, the radar output is stably around 24 bpm

What is interesting is that I also recorded the breath phase output, plotted it over time, and performed an FFT. The dominant frequency from the FFT matches the metronome setting.

The firmware version I am using is: v1.6.12

Has anyone else experienced the same issue?
Or is this a known behavior of the current firmware/algorithm?

Thank you.