diff options
Diffstat (limited to 'macros/sftrans.sci')
| -rw-r--r-- | macros/sftrans.sci | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/macros/sftrans.sci b/macros/sftrans.sci index f0c092e..9a59e61 100644 --- a/macros/sftrans.sci +++ b/macros/sftrans.sci @@ -11,22 +11,18 @@ // Email: toolbox@scilab.in function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop) //Transform band edges of a prototype filter (cutoff at W=1) represented in s-plane zero-pole-gain form (Frequency Transformation in Analog domain). - //Calling Sequence //[Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop) //[Sz, Sp] = sftrans (Sz, Sp, Sg, W, stop) //[Sz] = sftrans (Sz, Sp, Sg, W, stop) - //Parameters //Sz: Zeros. //Sp: Poles. //Sg: Gain. //W: Edge freuency of target filter. //stop: True(%T or 1) for high pass and band stop filters or false (%F or 0) for low pass and band pass filters. - //Description //Theory: Given a low pass filter represented by poles and zeros in the splane, you can convert it to a low pass, high pass, band pass or band stop by transforming each of the poles and zeros individually. The following table summarizes the transformation: - // Transform Zero at x Pole at x // ---------------- ------------------------- ------------------------ // Low Pass zero: Fc x/C pole: Fc x/C @@ -56,8 +52,6 @@ function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop) //algebra, you can derive the above formulae yourself by substituting the transform for S into H(S)=S-x for a zero at x or H(S)=1/(S-x) for a pole at x, and converting the result into the form: // // H(S)=g prod(S-Xi)/prod(S-Xj) - - //Examples //[Sz, Sp, Sg] = sftrans([1 2 3], [4 5 6], 15, 20, %T) // Output @@ -72,6 +66,7 @@ function [Sz, Sp, Sg] = sftrans (Sz, Sp, Sg, W, stop) // 20. 10. 6.6666667 // dependencies // + funcprot(0); [nargout nargin]= argn(); |