Time domain measurement method with calibration in frequency domain

摘要

A method for determining an electric voltage u(t) and/or an electric current i(t) of an HF signal in an electrical cable on a calibration plane by measuring in the time domain. Using a directional coupler, a first portion v3(t) of a first HF signal is decoupled, fed to a time domain measuring device, and a second portion v4(t) of a second HF signal is decoupled. The signal portions v3(t), v4(t) are converted into the frequency domain, then absolute wave frequencies in the frequency domain are determined and converted into the electric voltage u(t) and/or the electric current i(t). In a previous calibration step, the calibration parameters are determined, and the absolute wave frequencies on the calibration plane are determined using the calibration parameters (e00,r(Γ3, Γ4), e01,r(Γ3, Γ4), e10,r(Γ3, Γ4), e11,r(Γ3, Γ4)), wherein Γ3, Γ4 are the reflection factors of the inputs of the time domain measuring device.