Hi ad9361 experts: I read the datasheet, and I want to confirm one thing. When the tx bandwidth is 20MHz, the tx attenuation is 0dB, and the tx lo frequency is 1.44GHz, what will the output power of ad9361 be? According to my test, it` s about -20dBm. Is this normal?
Thanks a lot.
The output power depends on the type and the level of the signal that you are giving at input.
As per the datasheet, the max tx output power is 7.5dBm at 2.4GHz with a 1MHz tone at input.
We do not confirm on any data apart from the datasheet.
Thanks for your reply. AS the page 27 of datasheet:
I set the tx lo frequency to 2.3GHz, tx attenuation to 0, BW to 20MHz, and get waveform alike the picture above. So when frequency is 2.3GHz, and tx attenuation is 0, the ad9361` s output power is the highest power it can attain under this condition(about -20dBm)?
With tone with digital power of 0 dBFS you will see output power around +7 dBm. With modulated LTE carrier the measured power varies depending on backoff and PAR of the signal.
Are you measuring band power for the bandwidth of the signal ?
Thank you for your reply. I read the datasheet, and I get that when 1 MHz tone into 50 Ω load, the output power is around +7 dBm. Yes, I am measuring band power for the bandwidth of the signal. I am using 20M BW. What is the highest output power when the BW is 20M?
It depends on PAR and Back off of the digital signal. If you are getting +7 dBm for tone , you should get around -8 dBm or better for a 20MHz LTE signal without any extra digital back off.
Thanks for your reply. When I open the DDS mode, and set tx attenuation to 0, the tone I got is as below:
It` s about -1.89dBm, which is not as high as the datasheet describes.
Dose there something that I miss?
Is the HW custom hardware or evaluation board.?
If custom there could be a matching issue. Have you tried measuring power at other frequencies.
May be you can calibrate your analyzer with a known good signal from signal generator for accurate power measurement.
Thanks for your reply. Yes, the HW is custom hardware. I will try your method. Thanks a lot.
I tried to use ZED Board+AD-FMCOMMS3 to measure the output power of the one cw tone of tx1, and there is a parameter called scale(dBFS) in the ADI IIO Oscilloscope application. When I set this parameter to 0, the output power of the one cw tone can attain the level as the datasheet describe. Can this parameter be set in no-os software? What is it in no-os software?