Other Parts Discussed in Thread: CC256XCQFN-EM, CC2564
Hi,
We are now processing the FCC certification test for a CC2564C based module and seeing an issue on radiated emission test above 1GHz.
We observed a spurious emission power at the second harmonic frequency (4808MHz), where the QP power is around 65dBuV/m, AV power is around 62dBuV/m, the AV power exceeds the limit of 54dBuV/m. The DUT is operating at 2402MHz, DH5 packet type, 339 data length (duty cycle is around 75%).
We also made the conducted test to get the conducted power at 4804MHz with the same setup, and compared to TI's EVM whose part number is CC256xCQFN-EM, and we got below results.
Our module: -53dBm @ 4804MHz
CC256xCQFN-EM: --49dBm @ 4804MHz
Therefore, we studied the FCC test report of CC256xQFN-EM to see how the data looks like, we saw below data that TI uses -20dB duty cycle correction factor which is 10% duty cycle.
Here I attached the test report.
CC256x QFN EM FCC Test Report.pdf
The question is can I use this duty cycle? 10% seems to be a bit small. If I use 10% duty cycle, it will pass the test, but the test house told me it should be larger than 50% for DH5. 10% is not acceptable.
Regards,
Evan
