Calibration of a metallic access network analyzer

A calibration approach is proposed to compensate for the systematic errors when the input reflection coefficient of a metallic access network cable is obtained using single port measurements from an access network analyzer. The analyzer is a versatile instrument and uses optimal cable matching and internal balancing to achieve maximum measurement resolution. The analyzer uses test-leads connected to a fixed bridge structure, but with an adaptable balance and match impedance, and two variable synchronous acquisition channels so that the calibration can be split up into the non-parametric determination of the fixed part and a parametric determination of the variable part. The outcome of the non-parametric calibration is nine frequency dependent coefficients, and shows as an important side product the autobalance procedure. The parametric calibration will result in two 35 item sets of coefficients of rational functions in the S-domain. The parametric calibration depends on frequency domain system identification where the order of the numerator and denominator polynomials of the rational functions are not fixed.