About the 52840 chip module test CW signal

[zz19930722]

We used 52840 design and production of a module, with redio test this example test module test transmit power found in the main signal next to two high noise, we are not sure the cause of this noise and will produce the impact, Do we need to eliminate this distraction?can help answer?

[Kaja]

Hi,

I'm note able to see much in the picture. 

Are you suing NCS or SDK5? 

What frequency is the noise on? What is the carrier frequency? 

Have you gotten a HW review? If yes, what is the case ID? 

Best regards,
Kaja

[zz19930722]

Thank you for your reply, the following is my response to your questionz:
Are you suing NCS or SDK5? 
Let's use this NCS，github.com/.../radio_test

What frequency is the noise on? What is the carrier frequency? 
The tested signal is channel 19 on 802.15.4 with a software configuration of 0dBm. the main signal is actually generated at 2.4450400GHz with two symmetrical noises at 31.4KHz from the main signal. the noise level is -40.62dBm. We have tried switching channels and configuring different transmit powers and found that noise is generated in each channel and increases or decreases with the software configuration power.

Have you gotten a HW review? If yes, what is the case ID? 
yes，But it was commissioned on the mail to help review by the agent in China. If I need to confirm, can I send it to you in an undisclosed way to take another look?

[zz19930722]

In addition, we used a spectrum meter to test the software configuration of the transmit power and the actual output power, in the case of the configuration of 8dBm, CW signal will be small about 1dBm, 5MHz bandwidth channel power and software configuration power is about the same, is this reasonable? Not reasonable then may be caused by the problem?For example, the test method is not right or design problems, etc.Thank you very much！

Specific test parameters, please refer to the following chart：

This is our test environment：

0dBm，Channel 11  

8dBm，Channel 11  



0dBm，Channel 11  

8dBm，Channel 11  

[Kaja]

Hi,

try to comment out this line: https://github.com/nrfconnect/sdk-nrf/blob/main/samples/peripheral/radio_test/src/radio_test.c#L473 

Also try with DCDC enable and disabled. 

Here is an example of how we check the frequency accuracy:

Here is an example of how we check the power level of the carrier, 2nd and 3rd harmonic:

I will be out of office the next week on Easter vacation.

Best regards,
Kaja

Best regards,
Kaja