Broadband technology involves multiplexing or modulation of several different signals over high-frequency transmission lines. Many times one cable type is used to transmit from several to hundreds of different channels at a time. Demodulators are used at the receiving end to extract the individual signals from the trunk line. Crosstalk may cause noise in the system and is often times easily prevented by use of twisted pair cabling. Expressed in ohms, impedance contains both resistance and reactance.
Microphone cables are common line level signal carriers.
Electrostatic sparks or spiking from motors, neon, fluorescent lighting and other sources can become coupled onto the cables causing noise. Electrostatic charges are most disturbing on microphone or line signals because they are often amplified. Shielded cables or protective conduit provide an acceptable solution to electrostatic noise in many instances. Capacitance changes between inner conductors or conductors and the shield can cause interference. This internally produced noise is best corrected by using a cable with a stable dielectric insulating material.