Signal Source Level Calibration Using The FSMR3000

This application note demonstrates the use of the Measurement Receiver to calibrate the signal output level of a Signal Generator.

Calibration in this application is a two-step process.

► The absolute output level of the signal source, at a fixed level, is measured using a thermal power sensor (e.g. NRP50T), which in turn outputs its reading to the FSMR.

► Output power calibration over a wider dynamic range (to lower power) is performed by connecting the FSMR to the signal source directly, and sweeping the power of the signal source.

The FSMR offers a nominal total measurement uncertainty of <0.015 dB +/- 0.005 dB per 10dB step. At 1GHz, the power measurement range covers -152 dBm to +30 dBm. It is this intrinsic linearity, that the accuracy of the calibration relies upon.

Absolute power measurement uncertainty, for the NRP50T thermal power sensor used in this Application Note, is 0.040 dB to 0.143 dB.

This process may be repeated at multiple frequencies. Calibration values are automatically stored and managed by the FSMR. Measurement frequencies for calibrations are stored, will be automatically recalled by the FSMR, by re-selection of those frequencies.