RE: Channel sounding output shows the exact same data for longer durations

Vinayaka KS — Tue, 03 Mar 2026 16:00:38 GMT

I did not use the semaphore. Then I am assuming that with the obstacle blocking LOS, the tonal quality might have been bad, and I would have read the same values again.

Now, I have used the semaphore and will continue with the testing with this. Thanks for pointing this out.

Regards,
Vinayaka KS

RE: Channel sounding output shows the exact same data for longer durations

tesc — Tue, 03 Mar 2026 13:23:17 GMT

Hi,

[quote user=""]sometimes the data output is the same as the previous output[/quote][quote user=""]Is this because of the median filter? And if it is, the size of the filter is 9, so shouldn't I get new data after 9 windows? [/quote]

It could be, since the median (middle when sorted) value out of the 9 values in the window, could be the same several times in a row, if the new and old (falling out of the window) values are either both higher than the current median or lower than the current median. If this is the reason for repeated values, then you should expect only a few repeats, yes, since the repeated value would slide out of the window.

Please note also how in the Bluetooth: Channel Sounding Initiator with Ranging Requestor sample, in the while loop near the bottom of main(), it waits for the sem_distance_estimate_updated semaphore signalling that distance estimates are updated. If you do not use such a mechanism, but rather get the current value every time interval regardless, then you may also get the same output several times in a row, simply because the underlying data structure containing measurements has not been changed in the mean time. From what you describe, I assume this is mostly what you are currently seeing.

Regards,
Terje