172 Glossary of linear system terminology

Nyquist plot: graph in complex plane of $T(i\omega)$ for $-\infty<\omega<\infty$ ;

Open loop: system without feedback;

phase: (or phase shift) argument of the transfer function;

RHP: open right half-plane $\{z\in{\bf C}:\Re z>0\};$

s-domain: linear system in terms of Laplace transform variable $s$ ;

SFL: single feedback loop system;

SISO: single input and single output linear system;

state-space model: linear system in terms of functions of time $t$ ;

summing junction: operator for adding signals;

tap: operator for splitting signal;

${\bf t}$ : time, with $t\in(0,\infty)$ ;

transfer function: this $T(s)$ multiplies the Laplace transform of the input to get the Laplace transform of the output;

unit impulse function $\delta_{0}$ the unit point mass at time $t=0$ , also known as Dirac delta function.

${\bf\omega}$ : angular frequency