Abnormal spurious at ~2432MHz for nRF51422

RE: Abnormal spurious at ~2432MHz for nRF51422

Hungli3333 — Tue, 15 Oct 2019 01:26:05 GMT

It is for China SRRC regulation check.

RE: Abnormal spurious at ~2432MHz for nRF51422

ketiljo — Mon, 14 Oct 2019 09:17:06 GMT

The spurious are inband, so it's not easy to suppress.

The radio in the nRF51 series is the same as in the nRF24L-series as well. This has been on the marked for 1++ years and we haven't gotten any reports that this has been a problem.

What regulation paragraph are they referring to that requires inband spurious to be at -33 dBm?

RE: Abnormal spurious at ~2432MHz for nRF51422

Hungli3333 — Mon, 14 Oct 2019 09:11:44 GMT

Our test lab claimed that the regulation required on the spurious not greater than -33dBm and it is Ok on -36dBm today but do you know any circuit change to suppress this 16MHz clock harmonics to allow more margin on it?

RE: Abnormal spurious at ~2432MHz for nRF51422

ketiljo — Mon, 14 Oct 2019 08:38:37 GMT

The spurious you see is caused by harmonics of the 16 MHz system clock. This is normal and does not cause any problems with radio regulatory. The nRF52 have a completely different radio architecture, so you won't see this here.