Patent ID: 6567955
Filing Date: 2003-05-20
Classification: G06F

Abstract:
A method of approximating a distributed constant line, which employs an information processing apparatus to perform a process of approximating an object distributed constant line by a lumped constant circuit obtained by cascading a given unit lumped constant circuit in n stages, comprising the steps of:calculating a product &ggr;l of a propagation constant &ggr; of the object distributed constant line and a line length l of said distributed constant line, and storing said product; calculating cosh &ggr;l and sinh &ggr;l, using said &ggr;l, and storing said cosh &ggr;l and sinh &ggr;l; calculating an(&ggr;l), bn(&ggr;l) and cn(&ggr;l) that constitute elements of a transfer matrix of said lumped constant line, from functions an(x), bn(x) and cn(x) defined by following three expressions: an&it;(x)=&Sum;k=0n&it;(n+k-1)!&it;â€ƒn2&it;k-1&it;(n-k)!&it;â€ƒ&it;x2&it;k(2&it;k)!bn&it;(x)=&Sum;k=0n-1&it;(n+k)!n2&it;k+1&it;(n-k-1)!&it;â€ƒ&it;x2&it;k+1(2&it;k+1)!cn&it;(x)=&Sum;k=0n&it;(n2+k2)&it;(n+k-1)!n2&it;k+1&it;(n-k)!&it;â€ƒ&it;x2&it;k+1(2&it;k+1)!â€ƒputting x=&ggr;l and deciding n as a tentative value, and storing said an(&ggr;l), bn(&ggr;l) and cn(&ggr;l); comparing said cosh &ggr;l with an(&ggr;l), sinh &ggr;l with bn(&ggr;l), and sinh &ggr;l with cn(&ggr;l), respectively, to make a judgment on whether a result of comparison satisfies a predetermined condition, and, when said condition is not satisfied, repeating steps from said step of calculating said an(&ggr;l), bn(&ggr;l) and cn(&ggr;l), onward, changing the value of said n, until said result of comparison satisfies said condition; and deciding an approximate circuit, using n when said result of comparison satisfies said condition, in order to decide, as the approximate circuit, a lumped constant circuit that is obtained by cascading said unit lumped constant circuits in n stages.