Ultralinear Cathode Follower

Abstract

The design of a modified cathode follower circuit which possesses an extremely linear response and a voltage gain of essentially unity is presented. Analysis of the circuit shows that, in principle, the harmonic distortion may be made arbitrarily small, and at the same time the voltage gain may be made arbitrarily close to unity. The modification is applied to a White cathode follower where the increase in linearity and gain is accompanied by a decrease in the output impedance. A practical modified White follower having a measured intermodulation distortion of 2×10−5%, a calculated voltage gain of (1−10−6), and a calculated output impedance of 2×10−3 ohms is given.