What is the optimum power level for calibration?
In general, a calibration should be performed under the same stimulus/response conditions as the measurement. Thus calibrating at one power level (without amplifier) and then measuring at a different power level (with amplifier) is not ideal. However, the dynamic accuracy of the MW PNA products is extremely good, so that calibrating at a different power level does not pose a significant error (See chart for frequencies less than 20 GHz). The choice the user does have is to stay within the same power range (same attenuator setting), but to calibrate at a higher power level (without the amplifier) and then reduce the power level during the measurement (with the amplifier). Since the hardware setting is essentially the same, the accuracy is hardly affected. It is always better to calibrate at a higher power level (staying below compression), to reduce the uncertainty due to noise.For best measurement accuracy, select the measurement and calibration power levels such that the test setup po
