We found side-band noise at AD9363 output.
- Screen shots below show spectrum spot checks at Fc=473MHz, 515MHz, and 611MHz, BW=6MHz, always transmit.
- The side band noise is about 60MHz away from Fc at both lower and upper sides. The green marker indicates the lower one. But the upper one can be observed and measured as well.
- The 61.44MHz spike could be derived from the external 30.72MHz oscillator providing clock to AD9363.
This resulted in the emission test Fail in FCC regulation test (OurAntenna-OverTheAir-LabAntenna). The picture below shows one of the scan results in UL lab for Fc=473MHz. (Very similar to Fc=515MHz, and 611MHz)
- Is there any inside filter or configuration that could help eliminate or suppress this side-band noises?
- Any suggestions will be much appreciated!