Transfer characteristics of coaxial cable lines. widespread errors

The paper will present the technique and the results of calculations of signal spread in the coaxial cable with taking into account magnetic field diffusion into conductors. The through calculations of the transfer characteristics of the recording paths, including cable, became possible due to a rapid increase of computer memory and speed. The experimenters\´ widespread errors will be specified, that are connected with the use of the recording cable lines with matched load at the one end only. As a rule, because of a limited space the probes in the pulsed power systems are directly connected to the cable, and the matching resistance is mounted only on the receiving end of the cable. The differences in the wave resistance of the cable at high and low frequencies (≈12% for a 75 Ω cable and ≈18% for a 50 Ω cable) result in occurrence of specific signal anomalies, i.e. reflections that are often interpreted as noise or as a useful signal. These reflections are not small and make several percent. Desire to improve the accuracy of measurements due to a "calibration" of the cable line from the generator\´ pulse may lead to opposite results, i.e. introduction of the error of several dozen percent caused by a difference in the output impedance of the signal sources. The paper will provide the calculated transfer characteristics of the coaxial cables in case the current sources and voltage sources are used as generators. The presented technique for calculating the transfer characteristics was as well applied to calculate damping of the high-frequency oscillations occurring during discharges on the capacitor facilities.