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Poles of a Normalized Chebyshev TYPE 1 Analog Lowpass Filter
 Syntax `y = fnc1pole(`Norder, Ap`)` Include: `include spt\fnc1pole.oms` See Also fnbpole
``` ARGUMENTS:    INPUTS:       Norder = SCALAR. Requested order of transfer function. Coerced to                INTEGER before local processing. Norder >= 2.       Ap     = SCALAR. Passband ripple in dB, Ap > 0.0 dB. Coerced to                double for local processing.    RETURN: VECTOR, COLUMN, COMPLEX. Poles of Chebyshev lowpass filter. ```
Description ``` ```Returns the poles of a normalized lowpass Chebyshev TYPE 1 analog filter function as a COMPLEX column vector. ``` ```A Chebyshev TYPE 1 filter has equi-ripple behavior in the passband and monotonically increasing attenuation in the stopband. The requested filter order 'Norder' must be >= 2. The passband peak-to-peak ripple is set via parameter 'Ap' in dB, where Ap > 0.0dB (strictly positive). Due to the nature of Chebyshev functions, even order filters cannot have a gain of unity at 0 Hz as can odd order filters. Even order filters start at Ap dB down at 0 Hz and begin passband ripple characteristics from there. All filters are passive, i.e., they can a gain of 1.0 at most at any given frequency.

Example ``` ```Find the poles of a 7th order Chebychev 1, 0.5 dB normalized filter. ``` include spt\spthead.oms format complex "f12.8" Norder = 7;     # Filter Order Ap     = 0.5d0; # Passband Ripple [dB] fnc1pole(Norder,Ap) ``` Results in: ``` { ( -0.05533807,  0.97701031) ( -0.15505382,  0.78350144) ( -0.22405927,  0.43481050) ( -0.24868702,  0.00000000) ( -0.22405927, -0.43481050) ( -0.15505382, -0.78350144) ( -0.05533807, -0.97701031) } ``` Reference ``` ```Blinchikoff