Bode diagrams and 2-port networks

  • Lionel Warnes
Part of the Electrical and Electronic Engineering book series (EAEE)


OFTEN WE want to know how a circuit will behave as the frequency changes, apart from any transient response, particularly with devices such as filters. (To some extent any circuit containing reactive components acts as a filter, that is it attenuates more at some frequencies than at others.) Any network may be so arranged as to have a pair of input terminals (the input port) and another pair for output (the output port) as in figure 5.1a. The ratio of output voltage to input voltage is written
$${{V}_{o}}/{{V}_{{in}}}={{A}_{v}}\angle \phi $$
where Av (= |V o /V in |) is the amplitude response and ϕ the phase response of the circuit. Conventionally these are displayed together on a Bode diagram1, which is a plot of voltage gain (in dB, or 20log10Av) and phase against log frequency.


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Copyright information

© L.A.A. Warnes 1998

Authors and Affiliations

  • Lionel Warnes
    • 1
  1. 1.Department of Electronic and Electrical EngineeringLoughborough University of TechnologyUK

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