How can I create a signal that contains the sum of two cosine waves of equal amplitude at 40 Hz and 45 Hz

The sampling rate must be 1 kHz

Answer 1

[Stephan]

fs = 1000; % Sampling rate 1000 Hz = 1 kHz
t = 0:1/fs:1; % take a sample of 2 seconds with 1 kHz sampling rate 
f1 = 40; % Frequency 1
f2 = 45; % Frequency 2
omega_1 = 2*pi*f1; % omega 1
omega_2 = 2*pi*f2; % omega 2
result = cos(omega_1.*t) + cos(omega_2.*t); % calculate sum
plot(t,result) % plot results

[Ömer Sertt]

Thanks and I want to compute the power spectrum of that signal with a rectangular window of duration 2 seconds.Any idea?

[Stephan]

Maybe this link can help. Since i do not have access to DSP Toolbox i can not help with a code. Follow the examples given or ask a new question regarding the power spectrum - im pretty sure you will get help.

[Ömer Sertt]

Thanks for helping.

[Batuhan Osman Aynaci]

Thank You!