# ad9361 tx power of BW 20MHz

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.

Parents
• 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.

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)?

Thanks

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)?

Thanks

Children
• 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 ?

• Hi Vinod:

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?

Thanks

• 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.

• Hi Vinod:

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?

Thanks

• 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.