bode plot of particular case

[talking]

I trying to draw a mag/phase bode plot of my system as below. Sorry for poor drawing.



X(w)/2 ------>(gain=1, phase shift = 0)----------> a
X(w)/2 ------>(gain=1, phase shift = p(w))------> b

Then,

(a-b)-----> Y(w)

Transfer function = Y(w)/X(w) = 1-e^(-jp(w))



Anyone who can help draw the mag/phase bode plot using matlab or others?
I have a trouble with it, because the transfer function is not a typical form: e.g (s+1)/(s^2+2s+5) where s = jw

Thanks in advance.