--- a/main/control/inst/bstmodred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/bstmodred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -152,35 +152,16 @@
 ## performed on system @var{G} prior to order reduction.
 ## Default value is true if @code{G.scaled == false} and
 ## false if @code{G.scaled == true}.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ##
-## For the H-infinity norm, the best approximation problem is
-## unsolved so far.  Nevertheless, balanced truncation and related
-## methods can be used to obtain good approximations using this measure.
-##
-## Available approximation methods are the accuracy-enhancing square-root (SR)
-## or the balancing-free square-root (BFSR) versions of
-## the Balance & Truncate (BTA) or Singular Perturbation Approximation (SPA) 
-## model reduction methods for the ALPHA-stable part of the system.
-##
-## Unstable models are handled by separating the stable and unstable
-## parts additively, applying the model reduction only to the stable
-## part and by joining the reduced stable with the original unstable part.
-## The order of the reduced system can be selected by the user or
-## can be determined automatically on the basis of the computed
-## Hankel singular values.
-##
-## For MIMO models, proper scaling of input-output channels is of
-## utmost importance.  This can @strong{not} be done by the equilibration
-## option or the @command{prescale} command because these perform state
-## transformations only.  While enhancing numerics, state transformations
-## have no influence on the input-output behaviour and the magnitude of
-## the corresponding signals.  Since the algorithm calculates the
-## H-infinity norm of these signals, important behaviour of @var{G}
-## could be neglected just because the corresponding signals have smaller
-## numbers than those of other, less important effects of @var{G}.
-##
 ## BST is often suitable to perform model reduction in order to obtain
 ## low order design models for controller synthesis.
 ##

--- a/main/control/inst/btaconred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/btaconred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -205,6 +205,13 @@
 ## performed on @var{G} and @var{K} prior to order reduction.
 ## Default value is false if both @code{G.scaled == true, K.scaled == true}
 ## and true otherwise.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ## @strong{Algorithm}@*

--- a/main/control/inst/btamodred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/btamodred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -183,21 +183,15 @@
 ## This is done by state transformations.
 ## Default value is true if @code{G.scaled == false} and
 ## false if @code{G.scaled == true}.
-## Note that for @acronym{MIMO} models,.
-## @end table
-##
-## For @acronym{MIMO} models, proper scaling of both inputs and outputs
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
 ## is of utmost importance.  The input and output scaling can @strong{not}
 ## be done by the equilibration option or the @command{prescale} command
 ## because these functions perform state transformations only.
-## Signals should not be scaled simply to the range of, say, -1 to +1.
-## For all inputs (or outputs), a change from +1 to +2 should be of the
-## same importance for the model.
-## Think of a chemical reactor, the importance could be the cost to control this
-## reactor.  Then a change on each input from +1.5 to +2.0 would cost 50$.
-## Otherwise, important behaviour of @var{G} could be neglected just because
-## the corresponding signals have smaller numbers than those of other,
-## less important effects of @var{G}.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
+## @end table
+##
 ##
 ## Approximation Properties:
 ## @itemize @bullet

--- a/main/control/inst/cfconred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/cfconred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -119,6 +119,13 @@
 ## performed on system @var{G} prior to order reduction.
 ## Default value is true if @code{G.scaled == false} and
 ## false if @code{G.scaled == true}.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ## @strong{Algorithm}@*

--- a/main/control/inst/hnamodred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/hnamodred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -245,13 +245,16 @@
 ## performed on system @var{G} prior to order reduction.
 ## Default value is true if @code{G.scaled == false} and
 ## false if @code{G.scaled == true}.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ##
-## UNSTABLE (from bstmodred)
-##
-## MIMO (from bstmodred)
-##
 ## Approximation Properties:
 ## @itemize @bullet
 ## @item

--- a/main/control/inst/spaconred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/spaconred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -205,6 +205,13 @@
 ## performed on @var{G} and @var{K} prior to order reduction.
 ## Default value is false if both @code{G.scaled == true, K.scaled == true}
 ## and true otherwise.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ## @strong{Algorithm}@*

--- a/main/control/inst/spamodred.m	Mon Mar 05 18:46:32 2012 +0000
+++ b/main/control/inst/spamodred.m	Mon Mar 05 21:38:35 2012 +0000
@@ -182,6 +182,13 @@
 ## performed on system @var{G} prior to order reduction.
 ## Default value is true if @code{G.scaled == false} and
 ## false if @code{G.scaled == true}.
+## Note that for @acronym{MIMO} models, proper scaling of both inputs and outputs
+## is of utmost importance.  The input and output scaling can @strong{not}
+## be done by the equilibration option or the @command{prescale} command
+## because these functions perform state transformations only.
+## Furthermore, signals should not be scaled simply to a certain range.
+## For all inputs (or outputs), a certain change should be of the same
+## importance for the model.
 ## @end table
 ##
 ##