4. Calibration of the inverter I

To calibrate the inverter, the VV measures three signals of the calibration circuit R1–R2:


Complex of these signals is described by proper system of equations. Solution of this system (formula 38) gets the accurate deviation δ<sup>i</sup> of the inverter transfer coefficient from its nominal value "1."

$$\delta\_i = \delta\_{\text{it}} (1 + \delta\_{\text{kin}}) \tag{28}$$

After the calibration procedure, we know the real value of the phase shifter transfer coefficient with an uncertainty better than 1–3 ppm. μC makes this calibration procedure automatically at

Variational Calibration

45

http://dx.doi.org/10.5772/intechopen.74220

least every hour.

Figure 10. Some results of experimental investigations.

where.

δia ≈ <sup>δ</sup>iv 2 Ui3þUi<sup>1</sup> Ui2�Ui<sup>1</sup> ; δkia ≈ <sup>δ</sup>iv 2 Ui3�Ui<sup>1</sup> Ui2�Ui<sup>1</sup> ; δia and δkia are the approximate values of the transfer coefficients of the inverter I and calibration circuit R1-R2.
