19.5 : 부분 분수 확장에 의한 역 Z 변환

The inverse Z-transform is an essential tool used for converting a function from its frequency domain representation back to the time domain.

Consider the function X(z), which needs to be converted back to its time-domain representation.

To decompose X(z), the poles of the function are identified, and it is expressed in terms of these poles.

Each pole contributes a term to the partial fraction expansion.

The coefficients for each term in the expansion are determined by substituting specific values for z.

After determining all the coefficients, the function is reassembled in its decomposed form.

This new representation is more manageable.

Each fraction corresponds to known Z-transform pairs, making the inverse transformation simple.

The partial Fraction Method is an effective technique for finding the inverse Z-transform by decomposing a function into simpler fractions with distinct coefficients.

The inverse Z-transform is applied to each fractional term separately, resulting in a combination of delta functions, exponential sequences, and step functions, collectively representing the original time-domain sequence.