Karakteristisk impedans er for AC-signaler (eller højfrekvente-signaler). Karakteristisk impedans er et koncept i lang-linjetransmission. Under processen med signaltransmission i transmissionslinjen, på et punkt, hvor signalet ankommer, vil transmissionslinjen og referenceplanet mødes. Der dannes et elektrisk felt, og på grund af det elektriske felts eksistens genereres en øjeblikkelig lille strøm, og denne lille strøm eksisterer på hvert punkt i transmissionsledningen. Samtidig har signalet også en vis spænding, så i processen med signaltransmission vil hvert punkt på transmissionslinjen svare til en modstand, og denne modstand er den karakteristiske impedans af transmissionslinjen, vi nævnte.
The continuity of the characteristic impedance (ρ) basically depends on the stability of the ratio of the distribution parameters L{{0}} and C0. We all know Ohm's law: U=RI, where R is the resistance or resistance load, in ohms (Ω). Resistance is related to the resistivity (also known as conductivity) of metal materials, but in the process of high-frequency signal transmission, we also need to understand the transmission of the physical medium (such as twisted pair, coaxial wire, waveguide) that transmits high-frequency signals characteristics, which are different from low-frequency signals, this transmission characteristic is related to the conductive material of the transmission medium (such as copper or silver), conductivity (resistivity), geometry (most commonly cylindrical), distributed inductance (L0), distributed capacitance (C0), insulating material (dielectric constant), etc. are all related, but the influence of these distribution parameters and the dielectric constant of insulating material is often not considered during low-frequency signal transmission.
