From f4e1f6e84837c77dd49e6ec055efb1b110f7d573 Mon Sep 17 00:00:00 2001
From: Nicolas Tobler <nicolas.tobler@ost.ch>
Date: Mon, 30 May 2022 00:05:03 +0200
Subject: Added content, presentation

---
 buch/papers/ellfilter/python/elliptic2.py | 85 ++++++++++++++++++++++++++++---
 1 file changed, 78 insertions(+), 7 deletions(-)

(limited to 'buch/papers/ellfilter/python/elliptic2.py')

diff --git a/buch/papers/ellfilter/python/elliptic2.py b/buch/papers/ellfilter/python/elliptic2.py
index 92fefd9..29c6f47 100644
--- a/buch/papers/ellfilter/python/elliptic2.py
+++ b/buch/papers/ellfilter/python/elliptic2.py
@@ -6,13 +6,14 @@ import numpy as np
 import matplotlib
 from matplotlib.patches import Rectangle
 
+import plot_params
 
 def ellip_filter(N):
 
     order = N
     passband_ripple_db = 3
     stopband_attenuation_db = 20
-    omega_c = 1000
+    omega_c = 1
 
     a, b = scipy.signal.ellip(
         order,
@@ -34,14 +35,14 @@ def ellip_filter(N):
 
     FN2 = ((1/mag**2) - 1)
 
-    return w/omega_c, FN2 / epsilon2
+    return w/omega_c, FN2 / epsilon2, mag, a, b
 
 
 plt.figure(figsize=(4,2.5))
 
 for N in [5]:
-    w, FN2 = ellip_filter(N)
-    plt.semilogy(w, FN2, label=f"$N={N}$")
+    w, FN2, mag, a, b = ellip_filter(N)
+    plt.semilogy(w, FN2, label=f"$N={N}, k=0.1$", linewidth=1)
 
 plt.gca().add_patch(Rectangle(
     (0, 0),
@@ -53,7 +54,7 @@ plt.gca().add_patch(Rectangle(
 plt.gca().add_patch(Rectangle(
     (1, 1),
     0.01, 1e2-1,
-    fc ='green',
+    fc ='orange',
     alpha=0.2,
     lw = 10,
 ))
@@ -61,18 +62,88 @@ plt.gca().add_patch(Rectangle(
 plt.gca().add_patch(Rectangle(
     (1.01, 100),
     1, 1e6,
-    fc ='green',
+    fc ='red',
     alpha=0.2,
     lw = 10,
 ))
+
+zeros = [0,0.87,1]
+poles = [1.01,1.155]
+
+import matplotlib.transforms
+plt.plot( # mark errors as vertical bars
+    zeros,
+    np.zeros_like(zeros),
+    "o",
+    mfc='none',
+    color='black',
+    transform=matplotlib.transforms.blended_transform_factory(
+        plt.gca().transData,
+        plt.gca().transAxes,
+    ),
+)
+plt.plot( # mark errors as vertical bars
+    poles,
+    np.ones_like(poles),
+    "x",
+    mfc='none',
+    color='black',
+    transform=matplotlib.transforms.blended_transform_factory(
+        plt.gca().transData,
+        plt.gca().transAxes,
+    ),
+)
+
 plt.xlim([0,2])
 plt.ylim([1e-4,1e6])
 plt.grid()
 plt.xlabel("$w$")
 plt.ylabel("$F^2_N(w)$")
 plt.legend()
-plt.savefig("F_N_elliptic.pdf")
+plt.tight_layout()
+plt.savefig("F_N_elliptic.pgf")
 plt.show()
 
 
 
+plt.figure(figsize=(4,2.5))
+plt.plot(w, mag, linewidth=1)
+
+plt.gca().add_patch(Rectangle(
+    (0, np.sqrt(2)/2),
+    1, 1,
+    fc ='green',
+    alpha=0.2,
+    lw = 10,
+))
+plt.gca().add_patch(Rectangle(
+    (1, 0.1),
+    0.01, np.sqrt(2)/2 - 0.1,
+    fc ='orange',
+    alpha=0.2,
+    lw = 10,
+))
+
+plt.gca().add_patch(Rectangle(
+    (1.01, 0),
+    1, 0.1,
+    fc ='red',
+    alpha=0.2,
+    lw = 10,
+))
+
+plt.grid()
+plt.xlim([0,2])
+plt.ylim([0,1])
+plt.xlabel("$w$")
+plt.ylabel("$|H(w)|$")
+plt.tight_layout()
+plt.savefig("elliptic.pgf")
+plt.show()
+
+print("zeros", a)
+print("poles", b)
+
+
+
+
-- 
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