低通滤波器 双线性 sogi

fs = 10000%采样频率Hz
Ts = 1/fs%采样时间s
fc = 50%截止频率Hz
wc = 2*pi*fc%角频率rad/s
k0 = 1.414%增益
num = [0 0 k0*wc*wc]
den = [1 k0*wc wc*wc]
sysc =tf(num,den)
sysd = c2d(sysc,Ts,'tustin')
[numd,dend]=tfdata(sysd,'v')
a = vpa(numd,10)
b = vpa(dend,10)

fs =

       10000

Ts =

   1.0000e-04

fc =

    50

wc =

  314.1593

k0 =

    1.4140

num =

   1.0e+05 *

         0         0    1.3956

den =

   1.0e+04 *

    0.0001    0.0444    9.8696

sysc =
 
         1.396e05
  -----------------------
  s^2 + 444.2 s + 9.87e04
 
Continuous-time transfer function.

sysd =
 
  0.0003412 z^2 + 0.0006825 z + 0.0003412
  ---------------------------------------
          z^2 - 1.956 z + 0.9566
 
Sample time: 0.0001 seconds
Discrete-time transfer function.

numd =

   1.0e-03 *

    0.3412    0.6825    0.3412

dend =

    1.0000   -1.9556    0.9566

 
a =
 
[0.000341227301, 0.0006824546021, 0.000341227301]
 
 
b =
 
[1.0, -1.955588308, 0.9565535907]