Nonlinear Transfer Functions with Thyrite

Since the publication of a previous paper1 the uses of Thyrite2 in the synthesis of nonlinear transfer functions in analog computing have been greatly expanded. Moreover, new and considerably improved methods of Thyrite selection and matching have been developed. The present paper shows how rational exponents can be represented. Functions of the form y = kxn, with 1/¿ ¿ n ¿ 6 are readily obtained. Circuit configurations generating the functions 1 ¿ (2x/¿)1.74 and 1 ¿ [2/¿(x-¿/2)]1.74 which provide excellent approximations to the cosine and sine functions, respectively, are given and an improved quarter-square multiplier using Thyrite squaring is discussed. A study was also made of the physical factors influencing the performance and accuracy of Thyrite and quantitative experimental data regarding these factors are presented.