plotting a polinomial fraction over a strict range

Hello i have a product of the polider function which gave me two polynomial 'q' as numerator 'd' as denominator.

q=x+1

q=[1 1]

d=x^2+x+1

d=[ 1 1 1]

my expression is f=q/d and i want to plot it with x=0:0.001:3

tfplot doesnt have the option of ploting in a string x range.

What could be done?

Thanks.

Answer 1

[Star Strider]

I do not have the DSP System Toolbox, so I do not have tfplot.

Try this instead:

q=[1 1];
d=[1 1 1];
x=0:0.001:3;

trf = polyval(q, x) ./ polyval(d, x);

figure
plot(x, 20*log10(trf))
grid
xlabel('Frequency')
ylabel('q/d (dB)')