why is matlab giving me undefined variable cheby1?

clear all;

w1 = 2*pi*2000;

w2 = 2*pi*4000;

wn = [w1 w2];

Rp = 3;

[b,a]= chebyl(6,Rp,wn,'s');

[z,p,k] = cheby1(6,Rp,wn,'s');

subplot(2,1,1);

zplane(z,p);

H = zpk(z,p,k);

[h,w] = freqs(b,a,2000);

subplot(2,1,2);

n=20*log10(abs(h));

plot(w/(2*pi),n);

xlabel('Hz');

ylabel('Gain in db');

xlim([0 8000]);

title(' Chebyshev Type 1 Band Pass Filter');

COMMAND WINDOW ERROR

Undefined function or variable 'chebyl'.

Error in chebychev_band_test (line 11)

[b,a]= chebyl(6,Rp,wn,'s');

[william Litvin]

I checked if i have cheby1 installed in my computer

>> which cheby1

D:\studies\matlab\MATLAB Production Server\R2015a\toolbox\signal\signal\cheby1.m

Answer 1

[Walter Roberson]

Your code calls the function chebyl not cheby1 . Lower-case L where you need digit 1