nRF54L15 Channel Sounding: Fixed-frequency CS Tone output for FCC/CE certification testing

[shion]

Hello,

 

I would like to use the Bluetooth Channel Sounding feature on the nRF54L15 for regulatory RF certification testing (e.g., FCC, CE, or Japan Radio Law).

 

Is there a way to transmit the Channel Sounding (CS) Tone continuously on a fixed RF channel (fixed frequency) for certification measurements?

 

I am currently evaluating the Channel Sounding sample provided in NCS v3.2.3, but I have not been able to find a test mode or HCI command that allows continuous transmission of a CS Tone on a specific frequency.

 

For nRF54L15 and NCS v3.2.3, could you please advise whether there is a supported method to output a fixed-frequency CS Tone for certification purposes?

 

Ideally, I would like to transmit the CS Tone on a user-defined RF channel and measure it using a spectrum analyzer, without requiring a peer device.

 

If this is not currently supported, I would also appreciate any recommendations for the preferred test methodology or possible workarounds.

 

 

Additional information:

• Device: nRF54L15 DK
• NCS version: v3.2.3
• Purpose: Regulatory RF certification testing using a spectrum analyzer

Thank you.

[Einar Thorsrud]

Hi,

A channel sounding tone is an unmodulated carrier signal. You can enable that via UART by programming the device with the radio test sample (adjust the UART pins as needed for your device to use two pins you can access).

The radio test sample use channel numbering in 1 MHz steps where 0 is 2.400 GHz, 1 is 2.401 GHz etc. So for example to set up an unmodualted carrier at 2.404 GHz use this command sequence (optionally setting a Tx power, if not done, the default is 0 dBm):

start_channel 4
output_power 0dBm        # optional; pick a level your device supports
parameters_print         # optional: confirm channel = 4
start_tx_carrier