Frequency-domain analysis of nonlinear electronic circuits in a general purpose c.a.d. program in APL

The small-signal frequency-domain analysis of linear and nonlinear electronic circuits has been implemented in a general purpose c.a.d. program in APL. The techniques used include a parallel pivoting and ordering scheme, and APL-oriented parallel algorithms to enhance speed and save storage. An algorithm for solving simultaneous complex algebraic equations is implemented which has the advantages of leaving the circuit-matrix structure invariant in the d.c, a.c. and transient cases. A highly nonlinear circuit of 450 branches, analysed at 40 frequency points, took approximately 3 min of c.p.u. time on the IBM 370/168 machine and the program and data fitted in less than 112K bytes of storage. The turn-around time was approximately 8 min