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- ## Copyright (C) 1996,1998 Auburn University. All Rights Reserved.
- ##
- ## This file is part of Octave.
- ##
- ## Octave is free software; you can redistribute it and/or modify it
- ## under the terms of the GNU General Public License as published by the
- ## Free Software Foundation; either version 2, or (at your option) any
- ## later version.
- ##
- ## Octave is distributed in the hope that it will be useful, but WITHOUT
- ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- ## for more details.
- ##
- ## You should have received a copy of the GNU General Public License
- ## along with Octave; see the file COPYING. If not, write to the Free
- ## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
-
- save_var = page_screen_output;
- page_screen_output = 1;
- disp("Description of system data structure:")
- disp("A linear system is stored in a structure, and may be represented in")
- disp("ss (state space), tf (transfer function), and/or zp (zero-pole-gain)")
- disp("form.")
- disp(" ")
- disp("variables in all representations:")
- disp("inname: list of signal names (strings) containing name(s) of system ")
- disp(" inputs; see is_signal_list");
- disp("n: number of continuous states")
- disp("nz: number of discrete states")
- disp("outname: list of signal names (strings) containing name(s) of system ")
- disp(" outputs");
- disp(" ")
- disp("variables in all representations:(cont'd)")
- disp("sys: system status vector. This vector indicates both what")
- disp(" representation was used to initialize the system data structure")
- disp(" (called the primary system type) and which other representations")
- disp(" are currently up-to-date with the primary system type.")
- disp(" sys(0): primary system type")
- disp(" =0 for tf form")
- disp(" =1 for zp form")
- disp(" =2 for ss form")
- disp(" sys(1:3): indicate whether tf, zp, or ss, respectively, are")
- disp(" \"up to date\" (whether it is safe to use the variables")
- disp(" associated with these representations)")
- disp(" sys(1): = 1 if tf variables are up to date")
- disp(" = 0 else");
- disp(" sys(2): = 1 if zp variables are up to date")
- disp(" = 0 else");
- disp(" sys(3): = 1 if ss variables are up to date")
- disp(" = 0 else");
- disp("You can update alternative representations internally with the")
- disp("sysupdate command:")
- disp(" ")
- help sysupdate
- disp("===============================")
- disp("More variables common to all representations in system data structures:");
- disp("tsam: discrete time sampling interval ")
- disp(" =0 if system is purely continuous");
- disp(" >0 if system has discrete-time states or outputs");
- disp("yd: vector indicating which outputs are discrete time (i.e.,")
- disp(" produced by D/A converters) and which are continuous time.")
- disp(" yd(ii) = 0 if output ii is continuous, = 1 if discrete.")
- disp(" ")
- disp("===============================")
- disp("variables in tf representations (SISO only):")
- disp("num: vector of numerator coefficients")
- disp("den: vector of denominator coefficients")
- disp(" ")
- disp("===============================")
- disp("variables in zp representations (SISO only):")
- disp("zer: vector of system zeros")
- disp("pol: vector of system poles")
- disp("k: system leading coefficient")
- disp(" ")
- disp("===============================")
- disp("variables in ss representations:")
- disp("a,b,c,d: usual state-space matrices. If a system has both")
- disp(" continuous and discrete states, they are sorted so that")
- disp(" continuous states come first, then discrete states")
- disp(" ")
- disp("WARNING: some functions (e.g., bode) will not accept systems")
- disp("with both discrete and continuous states/outputs")
- disp("stname: list of signal names (strings) containing name(s) of system ")
- disp(" states");
- disp("===============================")
- disp("Object oriented programming:")
- disp("It is recommended that users do not directly access the internal")
- disp("variables themselves, but use the interface functions")
- disp(" fir2sys ss2sys tf2sys sys2fir")
- disp(" sys2ss sys2tf sys2zp syschtsam")
- disp(" sysdimensions sysgetsignals syssetsignals sysgettype")
- disp(" zp2sys")
- disp("to create/access internal variables. ");
- page_screen_output = save_var;
-