--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/+utils/@math/fq2ri2.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,32 @@
+% FQ2RI2 Convert frequency/Q pole/zero representation into real
+% and imaginary conjugate pairs. Returns [ri conj(ri)]
+%
+% ri= fq2ri2(f0, Q)
+%
+% M Hewitson 26-01-07
+%
+%
+% $Id: fq2ri2.m,v 1.2 2008/10/24 06:19:23 hewitson Exp $
+%
+
+function ri= fq2ri2(f0, Q)
+  
+  if(nargin==0)
+    disp('usage: ri = fq2ri2(f0, Q)')
+    return
+  elseif(nargin==1)
+    ri = (1/(2*pi*f0));
+  elseif(nargin==2)
+    if Q <= 0.5
+      disp('working on Q < 0.5') %ri =1/(2*pi*f0);
+    else
+      w0 = 2*pi*f0;
+      G = 1/(w0*w0);
+      re = -w0/(2*Q);
+      im = w0*sqrt(4*Q*Q-1)/(2*Q);
+      tri = complex(re,im);
+      ri = G.*[tri conj(tri)]';
+    end
+  end
+end
+% END