add DT test for bandwidth function

aWZHY0yQH81uOYvH · aWZHY0yQH81uOYvH · commit 1ccbbfd2d3c8 · 2026-03-18T12:26:46.000-07:00
diff --git a/control/tests/lti_test.py b/control/tests/lti_test.py
@@ -109,6 +109,11 @@ def test_bandwidth(self):
         np.testing.assert_allclose(sys1.bandwidth(), 0.099762834511098)
         np.testing.assert_allclose(bandwidth(sys1), 0.099762834511098)
 
+        # test a first-order discrete-time system, compared with matlab
+        sysd1 = tf([0.1, 0], [1, -0.9], 1)
+        np.testing.assert_allclose(sysd1.bandwidth(), 0.105207775532932)
+        np.testing.assert_allclose(bandwidth(sysd1), 0.105207775532932)
+
         # test a second-order system, compared with matlab
         wn2 = 1
         zeta2 = 0.001
