Channel Frequency mismatch

RE: Channel Frequency mismatch

ketiljo — Fri, 21 Apr 2023 13:05:16 GMT

https://infocenter.nordicsemi.com/topic/ug_nrf52833_dk/UG/dk/hw_rf_measure.html

RE: Channel Frequency mismatch

Suresh C — Fri, 21 Apr 2023 09:17:27 GMT

Hi,

Thank you for you response. I have tried changing the TX power of the transmitter(NRF52833 DK). That mean I vary the power to +8dBm but the maximum power I can see in spectrum analyzer is -24 dBm. It doesn't go beyond that.

RE: Channel Frequency mismatch

ketiljo — Fri, 21 Apr 2023 07:29:45 GMT

If you want to check the frequency of the carrier, it needs to be unmodulated. Else it's too wide. Set the span to 100 kHz and RBW to 200 Hz and try again. It should look like this:

RE: Channel Frequency mismatch

Suresh C — Thu, 20 Apr 2023 15:49:20 GMT

You mean unmodulated carrier will result in these data's. So how can I check the frequency of modulated signal using spectrum analyzer. Is there any way to check that?

Spectrum Analyzer Image:( Image when measuring 39th channel)

RE: Channel Frequency mismatch

ketiljo — Thu, 20 Apr 2023 14:19:06 GMT

That doesn't make much sense. The carrier frequency should be less than 30 ppm off, so a few 100 kHz at most.

Can you share a screenshot of the spectrum analyzer please?

Use a unmodulated carrier when you do these measurements. Also, when you use the radio test, the frequency is set at 2400 MHz + channel. This is not related to the BLE channel map. So channel 40 = 2440 MHz etc.

RE: Channel Frequency mismatch

Suresh C — Thu, 20 Apr 2023 12:13:12 GMT

This was the image I referred. the above image is based on BLE specification. I am attaching a image below that contains the data we got from the Spectrum analyzer.

RE: Channel Frequency mismatch

ketiljo — Thu, 20 Apr 2023 12:05:31 GMT

Can you show some screenshots?

RE: Channel Frequency mismatch

Suresh C — Thu, 20 Apr 2023 09:03:24 GMT

I am using FPC 1000 Spectrum analyzer and Radio check SDK from Nordic to test this.

RE: Channel Frequency mismatch

ketiljo — Wed, 19 Apr 2023 07:42:32 GMT

How do you test this? What FW and what spectrum analyzer are you using?