| CPC G06F 17/13 (2013.01) [G06F 17/16 (2013.01)] | 18 Claims |
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1. A non-linear characteristic calculating method to be executed by a computer, for calculating a non-linear characteristic of a non-linear device,
the computer including a processor and an external interface, and
the method comprising:
calculating, by the processor, the non-linear characteristic of the non-linear device based on a non-linear model comprising non-linear equations obtained by replacing constant coefficients of a linear state space representation that are also coefficients of a transfer function with functions of one state variable, and
outputting, via the external interface, a result of the non-linear characteristic,
wherein the one state variable indicates an internal state of the non-linear device,
wherein, when the non-linear equations are described in the state space representation which includes a matrix, a vector composed of state variables, an input, and an output, the vector indicates an internal state of the non-linear device and is distinct from the input, and the one state variable is a component of the vector,
wherein the calculating the non-linear characteristic calculates linear responses at bias points and transient responses of the non-linear device,
the one state variable is one of the state variables of non-linear state space representations as the non-linear model, and
the non-linear device is an electrical component,
wherein the method further comprises making, by the processor, the non-linear model with the functions fit linear responses at the bias points, by measuring impedance values at the bias points and providing the measured impedance values for use in modeling at the bias points, and identifying the functions relevant to the non-linear equations concerning the one state variable,
wherein the non-linear equations are described by the non-linear state space representations, in which:
the state variables are numbered,
one of the state variables with the first number is defined as the one state variable,
a time derivative of each of the state variables, except for one of the state variables with the last number, is equal to one of the state variables with a next number,
the time derivative of one of the state variables with the last number is equal to a sum of the input and a linear combination, the linear combination being calculated as inner product of a row vector and a column vector, respective elements of the row vector being first functions of the one state variable taken with a negative sign, and respective elements of the column vector being all of the state variables, and
the output is equal to a sum of:
a linear combination, the linear combination being calculated as inner product of another row vector and the column vector, respective elements of the another row vector being second functions of the one state variable,
a product of a third function of the input and the input, and
a product of a fourth function of the input and the time derivative of the input, or
the state variables are numbered,
one of the state variables with the last number is defined as the one state variable,
a time derivative of each of the state variables, except for one of the state variables with the first number, is equal to a sum of:
one of the state variables with a previous number; and
an opposite of a product of a fifth function of the one state variable and the one state variable; and
a product of a sixth function of the one state variable and the input,
the time derivative of one of the state variables with the first number is equal to a sum of:
an opposite of a product of a seventh function of the one state variable and the one state variable; and
a product of an eighth function of the one state variable and the input, and
the output is equal to a sum of:
the one state variable and
a product of a constant number and the input.
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