Multiterminal gyrator

Abstract

The multiterminal-gyrator concept is introduced as an extension of the well known 2-port device. In general, it is treated as having n input and m output terminals plus a reference or earthed terminal, common to both input and output. The (n + m + l)-terminal device is therefore mathematically described using an (n + mailorder admittance matrix. Both the mathematical characterisation and impedance-inverting properties of the multigyrator are shown to be directly analogous to those of its 2-port counterpart. An active realisation of the generalised multigyrator is proposed which uses unity-gain voltage and ± unity-gain current amplifiers. The method is quite general and uses « + mof each type of amplifier, a pair of amplifiers being connected to each of the n + m terminals. The actual gyrator transconductances are defined by an interconnecting network of resistors. The use of multigyrator capacitor networks to simulate inductor networks is shown to be possible and synthesis examples are given. Finally, the results of two experimental multigyrator filters are given.

Generation of Transconductance Grounded Capacitor Filters from LC Ladder Prototypes Based on Multi-Terminal Gyrator Principles

“…The impedance inverting property of the two port gyrator is well known and documented [3]. The corresponding property exists for the multi-gyrator on a multi-terminal basis.…”

“…The concept of the 2-port gyrator was introduced and defined as a non-reactive, loss free, anti-reciprocal network [3]. Using the voltages and currents as defined in figure (1.a) we may describe the three-terminal gyrator by a matrix equation of second order: A useful and well known property of the gyrator is that, if port (2) is loaded with an admittance y as shown in figure (1.b) the input admittance at port (1) is given by:…”

“…The concept of the three-terminal gyrator as a nonreactive loss-free anti-reciprocal device could be extended to multi-terminal devices [3]. One could define a multi-terminal gyrator or multi-gyrator as having (n) input and (m) output terminals with one additional common terminal.…”

“…It is clear that if the loading network described by Y is purely capacitive, the network presented at the (n) input terminals of the multi-gyrator and described by matrix (A) is purely inductive [3]. This property is used latter in the design of TGC filters.…”

“…In this work, a systematic technique for the realization of Transconductance Grounded Capacitor (TGC) circuits based on the principle of multi-terminal gyrator [3] is introduced. The TGC filters can be tuned electronically by applying a voltage or current biasing scheme as appropriate for the technology chosen.…”