Transmission Line Theory


Training Course | Transmission Line Theory for Digital Pulses

Module 1

  • Introduction.
  • Lumped and distributed parameters.
  • Differential equation for the uniform transmission line.
  • Characteristic Impedance.
  • Problem paper 1. e.g. Show that for a lossless line with a travelling wave moving in one direction, the energies associated with the electric and magnetic fields are equal.

Module 2

  • Incident and reflected waves.
  • Reflection coefficient.
  • Open circuit termination.
  • Short Circuit termination.
  • Lattice diagram.
  • Problem paper 2. e.g. A rectangular pulse of voltage 100V is propagated down a lossless line that has a Zo = 400Ω. The end of the line is open circuited. Plot the line voltage and current versus distance from the open end for different conditions.

    Module 3

    • Disconnection of supply.
    • Effect of source resistance.
    • Printed circuit board connections.
    • Characteristics of PCB traces. (an Integrated Device Technology Inc. application note)
    • Measurement of PCB trace parameters.
    • Problem paper 3. e.g. A lossless transmission line is uniformly charged to a voltage E throughout its length an is then open circuited at both ends. If a resistance R = Zo is suddenly connected across one end of the line, sketch the current waveform in the resistor.

      Module 4

      • Transmission line effects in interconnections.
      • Types of termination, parallel, series and others.
      • Problem paper 4. e.g. A 9 inch PCB trace is tested using the experimental technique described in the notes. If Vt is 4V and the td is 10 ns, determine the characteristic impedance of the trace and the propagation delay per unit length. The source impedance of the pulse generator is 50Ω and it develops a square wave emf of amplitude 6V.

        Module 5

        • Junctions of transmission lines.
        • The tapped transmission line.
        • Memory systems.
        • Problem paper 5. e.g. A transmission line system of defined parameters has a 100Ω resistor connected at the receiving end and a 100Ω resistor connected between the line conductors at the mid point of the line. The switch is closed at t = 0, sketch the voltage waveforms across the resistors.

          Module 6

          • Steady state sine wave operation.
          • Rise time and bandwidth.
          • Rules tell whether interconnections act like transmission lines.
          • Correct signal faults by implementing line analysis theory.
          • Quiz answers show how to handle connection problems.


            During the course a demonstration of reflection conditions will be carried out. The student will get the opportunity to see how different impedances both in cables and terminations affect the waveform on a scope.