Varying an Input to an Amplifier Model

Hello

I have written some Matlab code to describe the behaviour of a specific type of amplifier when supplied with two input signals out of phase with each other. In this code I have a set gain value (G) and a set amplitude value (A) and I am able to plot the result of this without any problem.

I would now like to plot the output with the input amplitude varying from -pi to +pi but when I try this, it results in the matrix dimensions not agreeing and was wondering if there is a simple way to resolve this? Below is the code I have written:

f1 = 100000;   %input signal 1 frequency
f2 = 200000;   %input signal 2 frequency
fs = 50*f1; %sampling frequency
Ta = 1/f1;  %input frequency period
Ts = 1/fs;  %sampling frequency period
t = (0:Ts:50*Ta);  %timing and step size
A = (-pi:pi);  %Fixed amplitude value
G = 10;  %Gain of amplifiers

S1 = cos(2*pi*f1*t + acos(A)); %Input signal 1
S2 = cos(2*pi*f2*t - acos(A)); %Input signal 2

Sout = G*(S1+S2); %Combined output signal
plot (Sout);

Any help with this would be much appreciated.

Regards

Dan

Answer 1

[Mathieu NOE]

hello

you have to make A and t the same size to make it work

so this is it :

f1 = 100000;   %input signal 1 frequency
f2 = 200000;   %input signal 2 frequency
fs = 50*f1; %sampling frequency
Ta = 1/f1;  %input frequency period
Ts = 1/fs;  %sampling frequency period
t = (0:Ts:50*Ta);  %timing and step size
A = linspace(-pi,pi,length(t));  %Fixed amplitude value
G = 10;  %Gain of amplifiers
S1 = cos(2*pi*f1*t + acos(A)); %Input signal 1
S2 = cos(2*pi*f2*t - acos(A)); %Input signal 2
Sout = G*(S1+S2); %Combined output signal
plot (Sout);