Prev Next polbes

Bessel polynomials of Order N
Syntax polbes(Norder, a)
Include: include spt\polbes.oms
See Also fnbpole , fnc1pole

ARGUMENTS:
   INPUTS:
      Norder = SCALAR. Requested order of polynomial. Coerced to
               INTEGER before local processing. Norder >= 2.
      a      = VECTOR, COLUMN, for return (type disregarded on input).
               Polynomial coefficients. Type DOUBLE.
   RETURN: novalue. Polynomial returned in argument 'a'.

Description

Returns the coefficients of Bessel polynomials as a DOUBLE column vector 'a'. These polynomials are commonly used as the basis for analog Bessel filters which approximate constant group delay. The coefficients form a polynomial as follows:

a => a(1) + a(2)*s + a(3)*s^2 + ...

Order 'Norder' must be >= 2.

Example

Find the coefficients of a 6th order Bessel polynomial.

O>a = novalue
O>polbes(6,a)
O>a
{
10395
10395
4725
1260
210
21
1
}

Reference

Blinchikoff and Zverev, "Filtering in the Time and Frequency Domains", Krieger, Malabar, FL. 1987 (Reprint Edition)