fix docstring example errors (in newly included functions)

Author: murrayrm

control/bdalg.py

@@ -541,26 +541,20 @@ def combine_tf(tf_array):
     --------
     Combine two transfer functions
 
-    >>> s = control.TransferFunction.s
-    >>> control.combine_tf([
+    >>> s = ct.tf('s')
+    >>> ct.combine_tf([
     ...     [1 / (s + 1)],
     ...     [s / (s + 2)],
     ... ])
-    TransferFunction([[array([1])], [array([1, 0])]],
-                     [[array([1, 1])], [array([1, 2])]])
+    TransferFunction([[array([1])], [array([1, 0])]], [[array([1, 1])], [array([1, 2])]])
 
     Combine NumPy arrays with transfer functions
 
-    >>> control.combine_tf([
+    >>> ct.combine_tf([
     ...     [np.eye(2), np.zeros((2, 1))],
-    ...     [np.zeros((1, 2)), control.TransferFunction([1], [1, 0])],
+    ...     [np.zeros((1, 2)), ct.tf([1], [1, 0])],
     ... ])
-    TransferFunction([[array([1.]), array([0.]), array([0.])],
-                      [array([0.]), array([1.]), array([0.])],
-                      [array([0.]), array([0.]), array([1])]],
-                     [[array([1.]), array([1.]), array([1.])],
-                      [array([1.]), array([1.]), array([1.])],
-                      [array([1.]), array([1.]), array([1, 0])]])
+    TransferFunction([[array([1.]), array([0.]), array([0.])], [array([0.]), array([1.]), array([0.])], [array([0.]), array([0.]), array([1])]], [[array([1.]), array([1.]), array([1.])], [array([1.]), array([1.]), array([1.])], [array([1.]), array([1.]), array([1, 0])]])
     """
     # Find common timebase or raise error
     dt_list = []
@@ -635,7 +629,7 @@ def split_tf(transfer_function):
     --------
     Split a MIMO transfer function
 
-    >>> G = control.TransferFunction(
+    >>> G = ct.tf(
     ...     [
     ...         [[87.8], [-86.4]],
     ...         [[108.2], [-109.6]],
@@ -645,7 +639,7 @@ def split_tf(transfer_function):
     ...         [[1, 1], [1, 1]],
     ...     ],
     ... )
-    >>> control.split_tf(G)
+    >>> ct.split_tf(G)
     array([[TransferFunction(array([87.8]), array([1, 1])),
             TransferFunction(array([-86.4]), array([1, 1]))],
            [TransferFunction(array([108.2]), array([1, 1])),

control/lti.py

@@ -575,18 +575,18 @@ def bandwidth(sys, dbdrop=-3):
     ValueError
         if 'dbdrop' is not a negative scalar
 
-    Example
-    -------
+    Examples
+    --------
     >>> G = ct.tf([1], [1, 1])
     >>> ct.bandwidth(G)
-    0.9976
+    np.float64(0.9976283451102316)
 
     >>> G1 = ct.tf(0.1, [1, 0.1])
     >>> wn2 = 1
     >>> zeta2 = 0.001
     >>> G2 = ct.tf(wn2**2, [1, 2*zeta2*wn2, wn2**2])
     >>> ct.bandwidth(G1*G2)
-    0.1018
+    np.float64(0.10184838823897456)
 
     """
     if not isinstance(sys, LTI):

control/xferfcn.py

@@ -1247,8 +1247,8 @@ def _isstatic(self):
     #: The ``s`` constant can be used to create continuous time transfer
     #: functions using algebraic expressions.
     #:
-    #: Example
-    #: -------
+    #: Examples
+    #: --------
     #: >>> s = TransferFunction.s                               # doctest: +SKIP
     #: >>> G  = (s + 1)/(s**2 + 2*s + 1)                        # doctest: +SKIP
     #:
@@ -1260,8 +1260,8 @@ def _isstatic(self):
     #: The ``z`` constant can be used to create discrete time transfer
     #: functions using algebraic expressions.
     #:
-    #: Example
-    #: -------
+    #: Examples
+    #: --------
     #: >>> z = TransferFunction.z                               # doctest: +SKIP
     #: >>> G  = 2 * z / (4 * z**3 + 3*z - 1)                    # doctest: +SKIP
     #: