Fully Integrated Selectivity at High Frequency Using Gyrators

An electronic gyrator is a two-port capable of transforming a capacitor into an inductance and therefore allows one to construct a tuned circuit using only transistors, resistors and capacitors. At frequencies below say 1 MHz it is possible to simulate inductance of high purity, but the value of capacitance required demands the use of discrete capacitors. The cost advantage of monolithic circuitry is therefore denied, but very high performance tuned circuits are possible.