Confused on making a function..

1 visualizzazione (ultimi 30 giorni)
Edmund Paul Malinowski
Edmund Paul Malinowski il 20 Nov 2015
Risposto: Star Strider il 20 Nov 2015
Hey all,
I understand functions to a degree or the basic principles but i'd ideally like to perform something quite complex as a function rather than a for loop i have it in already. Below is my code:
BandPassALL{1}=designfilt('bandpassiir', 'StopbandFrequency1', 247, 'PassbandFrequency1', 255, 'PassbandFrequency2', 269, 'StopbandFrequency2', 277, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{2}=designfilt('bandpassiir', 'StopbandFrequency1', 279, 'PassbandFrequency1', 287, 'PassbandFrequency2', 301, 'StopbandFrequency2', 309, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{3}=designfilt('bandpassiir', 'StopbandFrequency1', 315, 'PassbandFrequency1', 323, 'PassbandFrequency2', 337, 'StopbandFrequency2', 345, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{4}=designfilt('bandpassiir', 'StopbandFrequency1', 335, 'PassbandFrequency1', 343, 'PassbandFrequency2', 357, 'StopbandFrequency2', 365, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{5}=designfilt('bandpassiir', 'StopbandFrequency1', 377, 'PassbandFrequency1', 385, 'PassbandFrequency2', 399, 'StopbandFrequency2', 407, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{6}=designfilt('bandpassiir', 'StopbandFrequency1', 425, 'PassbandFrequency1', 433, 'PassbandFrequency2', 447, 'StopbandFrequency2', 455, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
BandPassALL{7}=designfilt('bandpassiir', 'StopbandFrequency1', 479, 'PassbandFrequency1', 487, 'PassbandFrequency2', 501, 'StopbandFrequency2', 509, 'StopbandAttenuation1', 60, 'PassbandRipple', 1, 'StopbandAttenuation2', 60, 'SampleRate', 44100);
for i=1:7;
for j = 1:1:length(Filter_Out_Pos{i});
if (Filter_Out_Pos{i} > 0.5)
Clean_Sig{i}(j) = 1;
subplot(7,1,i), plot(Clean_Sig{i});
Wave is the samples vector of an audioread. I only want to possibly convert the for loop part into a function. As it is at the moment, it doesn't do anything, well i'm sure it does as my hd fan goes crazy but it doesn't produce any plots or weirdly any errors so although i thought the line:
Clean_Sig{i}(j) = 1;
...would be an issue as it looks wrong, it doesn't appear so..
Apart from a function, is there a quicker way to perform what i need. Loops and ifs are slow in matlab aren't they?

Risposte (1)

Star Strider
Star Strider il 20 Nov 2015
I am not certain what you want to do from reading your code. My filter design procedure for a bank of filters is:
Fs = 8200; % Samping Frequency (Hz)
Fn = Fs/2; % Nyquist Frequency
pf = linspace(20,4000,17); % Passband Frequencies
cf = pf(1:end-1)+(pf(2)-pf(1))/2; % Centre Frequencies
for k1 = 1:length(cf)
[z(k1,:),p(k1,:),k(k1)] = butter(7, [pf(k1) pf(k1+1)]/Fn);
[sos{k1},g{k1}] = zp2sos(z(k1,:),p(k1,:),k(k1));
[h(k1,:),w(k1,:)] = freqz(sos{k1},512,Fs);
plot(w([1 16],:), abs(h([1 16],:)))
% axis([0 0.2 ylim])
hold on
for k1 = 2:16
hold off
This snippet just designs them and displays their transfer functions. It would be easy to add code that actually filters a signal for each filter, then store the results in a matrix. I always use the filtfilt function to do the actual filtering, since it does not induce the phase distortion that filter does.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by