directional coupler

directional coupler

   <communications> (tap) A {passive} device used in {cable}
   systems to divide and combine radio frequency signals.  A
   directional coupler has at least three ports: line in, line
   out, and the tap.  The signal passes between line in and line
   out ports with loss referred to as the {insertion loss}.  A
   small portion of the signal power applied to the line in port
   passes to the tap port.  A signal applied to the tap port is
   passed to the line in port less the tap attenuation value.
   The tap signals are isolated from the line out port to prevent
   reflections.  A signal applied to the line out port passes to
   the line in port and is isolated from the tap port.  Some
   devices provide more than one tap output line (multi-taps).

   (1995-12-23)