Hello,
You can refer to the below code to create a sinusoidal signal of different frequencies for different time interval.
% Define the time intervals and frequencies
t1 = linspace(0, pi/2, 1000); % frequency 10 Hz
t2 = linspace(pi/2, pi, 1000); % frequency 20 Hz
t3 = linspace(pi, 3*pi/2, 1000); % frequency 30 Hz
f1 = 10;
f2 = 20;
f3 = 30;
% Create sinusoidal signals for each interval
y1 = sin(2*pi*f1*t1);
y2 = sin(2*pi*f2*t2);
y3 = sin(2*pi*f3*t3);
% Concatenate signals and time intervals
t = [t1 t2 t3];
y = [y1 y2 y3];
% Plot signal
plot(t, y)
xlabel('Time')
ylabel('Amplitude')
title('Sinusoidal Signal with Different Frequencies')
