Hi Venya,
Here is a revised version of your code.
function output = analog_filter1()
% Simulated analog filter used in Problem 1.3
Ts = 0.001;
N = 1000;
t = (0:N-1) * Ts;
make_an_array = [2 10 15 20 30 40 50 60 80 90 100 150 200 300 400];
f = make_an_array;
max_values = zeros(1, length(f)); % Array to store maximum values
for i = 1:length(f)
input = sin(2 * pi * f(i) * t); % Generate sine wave for each frequency
[b, a] = butter(4, 0.02, 'high');
[b1, a1] = butter(2, 0.12);
input = filter(b1, a1, input);
output = filter(b, a, input);
max_values(i) = max(output); % Store the maximum value of the output
end
G = 20 * log10(max_values); % Calculate 20 log of the maximum values
semilogx(f, G, 'x');
xlabel('Frequency in Hz');
ylabel('Gain (dB)');
grid on;
disp(max_values); % Display the maximum values
end
Key Changes:
- The input parameter has been reomved and the function now generates the input internally.
- Generate sine waves for each frequency in the array with the help of a loop.
- Use an array max_values to store the maximum output values for each frequency.
- Calculate the 20 log of the maximum values and plot them using semilogx.
Explanation:
- For each frequency in the array f, a sine wave is generated.
- The sine wave is filtered using two Butterworth filters.
- The maximum value of the filtered output is stored in the max_values array.
- The 20 log of the maximum values is plotted against the frequency array using semilogx.
I have confirmed on my end that the above changed resolve the “Subscripted assignment dimension mismatch” error and correctly plot the desired graph.
