i want to plot freq response of FIR filter

the filter is :

w = linspace(0,pi);

b0=1

b1=-2

b2=4

b=b0*conv(b1,b2)

freqz(b,w)

it gives me an error

Answer 1

[Mathieu NOE]

hello

try this

b= [1 -2 4];
freqz(b,1)

[Sliman Izz]

thank you

[Mathieu NOE]

my pleasure !