https://devzone.nordicsemi.com/f/nordic-q-a/124538/the-meaning-of-iq-data-in-the-channel-sounding-example-why-not-a-conjugate-multiplicationThe meaning of IQ data in the channel sounding example I am trying to use IQ data to calculate distance using the routines ` channel_sounding_ras_initiator ` and ` channel_sounding_ras_reflector `. In the code, the structure ` cs_de_report_t ` containsen-USTelligent Community 13Fri, 03 Oct 2025 10:17:29 GMThttps://devzone.nordicsemi.com/thread/550576?ContentTypeID=1Fri, 03 Oct 2025 10:17:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1e0689ba-ebb3-4bc2-892b-ec4d43e0b5b4tesc<p>Hi,</p> <p>From what we can figure out, the Zephyr implementation of Channel Sounding distance estimation stems from this description from the Bluetooth core specification:<br /><a href="https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-60/out/en/architecture,-change-history,-and-conventions/architecture.html#UUID-a8d03618-5fcf-3043-2198-559653272b1b">https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-60/out/en/architecture,-change-history,-and-conventions/architecture.html#UUID-a8d03618-5fcf-3043-2198-559653272b1b</a></p> <p>In other words, a different approach than the one described at&nbsp;<a id="" href="https://www.bluetooth.com/channel-sounding-tech-overview/">https://www.bluetooth.com/channel-sounding-tech-overview</a>&nbsp;</p> <p>Regards,<br />Terje</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/549742?ContentTypeID=1Thu, 25 Sep 2025 02:30:07 GMT137ad170-7792-4731-bb38-c0d22fbe4515:048cb9ed-e3ee-4485-915e-6ac143013213qianjunwang<p>Hi,</p> <p><span>Thank you for your attention and reply. </span></p> <p><span>From the perspective of the algorithm&#39;s results, directly multiplying does indeed yield an accurate distance estimate. </span></p> <p><span>I suspect that the actual engineering implementation might differ from what was described above.</span></p> <p><span>Best regards,</span></p> <p><span>qianjunwang</span></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/549727?ContentTypeID=1Wed, 24 Sep 2025 19:28:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bba87203-0512-4333-819d-971a654cfdcdtesc<p>Hi,</p> <p>I have looked into this, and from what I can tell it looks like you are correct. In other words: It looks like phases are summed, not diffed.</p> <p>I will need to look further into it to confirm, and expect to get back to you within a few days.</p> <p>Regards,<br />Terje</p><div style="clear:both;"></div>