Write a signal whose phase increases

For eg I have an input : exp(1i*0) with a particular phase, I wish to write another signal whose phase goes till 180 degrees as max. And I have a theta/phi in which I can put values like pi/2 or pi/3 etc. Something like an increasing function which reaches 180 as max phase.. and can start from any phi/theta we put in. I dont want a function for all of this- like 0 to increasing to 180. but just the increasing thing.. how to put in code? How can I put phi(t) from phase 2 in code.

I tried- but it doesn't give me the desired result - if someone can correct it.

theta = 3*pi./4; %% 
ta =[-2 0]; % 0 phase  -- input1
tb = [0 2];  %% this is where the increasing phase should be max being 180
tc = [2 4]; % 180 degree phase reversal - see input3
 a = -theta./(tb(2)-tb(1));
input1= exp(1i*0);
input2 = = @(t) 1.*exp(1i*(pi + a.*(t-tb(1)))); %%% what is wrong here??? 
input3 =exp(1i*pi);

( I think i am not putting 180 as the max maybe?) I am not sure how to do write this -it seems to simple to think and imagine but putting it in code is just not working for me.

[darova]

Show your whole code. You have no "t" in your handle function

[STP]

Hi darova, Just edited.

Answer 1

[darova]

See in wiki Two point line equation

[STP]

Hi darova.

Thanks for your message, what you have messaged above is linear modulation - I wish to achieve non linear moduation