How can I calculate default emission energy, set by DW1000 when use smartpower feature?
Assume, I have pretty simple recommended RF tract with balun and WB002 antenna implemented in single PCB .
I know, the exact value depends upon real HW implementation, but need some starting point…
The DW1000 IC has default power levels hard-coded which should get you reasonably close to the regulatory emissions level. See the DW1000 User Manual for details.
To actually measure the transmit power, you can make a radiated setup by measuring the power with a measuring antenna (preferably a horn antenna) and a spectrum analyser. You would need to adjust the measured power to allow for the path loss between DUT and horn antenna aswell as horn antenna gain, cable losses, etc.
You could also measure the power by soldering an RF connection to your board at the feed point of its antenna and measuring on a spectrum analyser. Adjust the DW1000 power setting to get to the regulatory limit minus the maximum antenna gain (e.g. 3.3 dBi for WB002 in Channel 5).
Measuring over the air is more accurate and of course this is what is ultimately done during certification testing.
Hi! thank you very much for clues!