From 05d75b0f467b2535db538ecaee461cf0c8b637d1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andreas=20M=C3=BCller?= Date: Mon, 27 Jun 2022 20:17:16 +0200 Subject: add stuff for elliptic filters --- .../110-elliptisch/uebungsaufgaben/landen.m | 60 ++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 buch/chapters/110-elliptisch/uebungsaufgaben/landen.m (limited to 'buch/chapters/110-elliptisch/uebungsaufgaben/landen.m') diff --git a/buch/chapters/110-elliptisch/uebungsaufgaben/landen.m b/buch/chapters/110-elliptisch/uebungsaufgaben/landen.m new file mode 100644 index 0000000..bba5549 --- /dev/null +++ b/buch/chapters/110-elliptisch/uebungsaufgaben/landen.m @@ -0,0 +1,60 @@ +# +# landen.m +# +# (c) 2022 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule +# +N = 10; + +function retval = M(a,b) + for i = (1:10) + A = (a+b)/2; + b = sqrt(a*b); + a = A; + endfor + retval = a; +endfunction; + +function retval = EllipticKk(k) + retval = pi / (2 * M(1, sqrt(1-k^2))); +endfunction + +k = 0.5; +kprime = sqrt(1-k^2); + +EK = EllipticKk(k); +EKprime = EllipticKk(kprime); + +u = EK + EKprime * i; + +K = zeros(N,3); +K(1,1) = k; +K(1,2) = kprime; +K(1,3) = u; + +format long + +for n = (2:N) + K(n,1) = (1-K(n-1,2)) / (1+K(n-1,2)); + K(n,2) = sqrt(1-K(n,1)^2); + K(n,3) = K(n-1,3) / (1 + K(n,1)); +end + +K(:,[1,3]) + +pi / 2 + +scd = zeros(N,3); +scd(N,1) = sin(K(N,3)); +scd(N,2) = cos(K(N,3)); +scd(N,3) = 1; + +for n = (N:-1:2) + nenner = 1 + K(n,1) * scd(n, 1)^2; + scd(n-1,1) = (1+K(n,1)) * scd(n, 1) / nenner; + scd(n-1,2) = scd(n, 2) * scd(n, 3) / nenner; + scd(n-1,3) = (1 - K(n,1) * scd(n,1)^2) / nenner; +end + +scd(:,1) + +cosh(2.009459377005286) -- cgit v1.2.1