Solution
The nominal maximum power value in the USRP manual is the value measured with a single frequency signal transmitted.
The maximum output power of different frequency points is also different, which is related to the frequency response of the system.
The maximum output power is related to the gain of the USRP front-end amplifier, and the measurement results vary with the value of the gain.
The method of modifying the gain can refer to the following figure. Modify the
Amplitude value of
Generate Waveform(Multi-Array).vi.
Take
USRP-2953 as an example. If we want to get the maximum output power:
- Run Tx Streaming (Host).vi send a signal with a frequency of 2GHz;
- Set the Output Power parameter to 20dbm;
- Set the Amplitude parameter to 0.5;
- The signal power measured by the spectrum analyzer is 12.98dbm;
- Set the Amplitude parameter to 1;
- The signal power measured by the spectrum analyzer is 18.53dbm (Maximum output power: 17 dBm to 20 dBm);