CST2013: Filter Analysis / Tchebychev-Factors

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The macro computes the g-values for a prototype low pass filter of type “r;Tchebychev”. For a user given bandwidth and return loss the group delays and coupling bandwidths are printed and provide useful information for the tuning of band pass filters.

User Dialog and a typical Output:

Tchebychev Filter

Order           = 4

Bandwidth       = 36 MHz

Passband ripple = 0,01 dB   (1,100747 VSWR)

Return loss     = -26,3828 dB

Normed g values:

g1 = 0,7129

g2 = 1,2004

g3 = 1,3213

g4 = 0,6476

g5 = 1,1008

Corresponding coupling coefficients in MHz:

k_E   = 50,5

k1_2  = 38,92

k2_3  = 28,59

k3_4  = 38,92

k_out = 50,5

Group Delay Time

t_d1 = 12,606 ns