This commit is contained in:
Arthur Lu 2021-12-08 21:03:25 -08:00
commit a1a5e875b2
6 changed files with 17 additions and 186 deletions

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.DS_Store vendored

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function output_y = DarellbandpassFilter(y,Fs,LOW,MED,HIGH)
Len = length(y);
F = Fs * (-Len/2 : (Len/2 - 1))/Len ;
Mod_Freq = fftshift(fft(y));
lenf = length(F);
output = 0 .* Mod_Freq; % zero array of len f
for n = 1:lenf
if ((LOW < abs(F(n))) && HIGH > abs(F(n)))
output(n) = 1;
else
output(n) = 0;
end
end
filtered_Mod_Freq = fftshift(Mod_Freq .* output);
output_y = real(ifft(filtered_Mod_Freq));
end

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filename = '/Users/DarellCHUA/OneDrive - UC San Diego/FA2021/ECE 45/SynthesizerProject/Be Epic.mp3';
[y,Fs] = audioread(filename);
lengthy = length(y);
new_y = zeros(1,lengthy);
for n = 1:lengthy
new_y(n) = y(n,1) + y(n,2);
end
y = new_y;
Time = (length(y)-1)/Fs;
Freq = 200; %Hz
Time = 20;
LFO = 1; %Hz
RangeFs = [20 22050];
Fs = 2*RangeFs(2); %should be 44.1 khz
x = 0:1/Fs:Time;
Len = length(x);
y = sin(Freq*2*pi*x); %sin wave
beats = 1;
y = y + sin((Freq+beats)*2*pi*x); %adding beats based on superposition
y = y + sin((2*Freq)*2*pi*x);
y = y + sin((2*Freq+beats)*2*pi*x);
y = y + sin((2*Freq+5)*2*pi*x);
y = y + sin((2*Freq+beats+5)*2*pi*x);
y = y + sin((3*Freq)*2*pi*x);
y = y + sin((3*Freq+beats)*2*pi*x);
y = y + sin((3*Freq+5)*2*pi*x);
y = y + sin((3*Freq+beats+5)*2*pi*x);
y = y + 5*sin((10)*2*pi*x);
y = y + sin((10*Freq+5)*2*pi*x);
y = y + square(Freq*2*pi*x); %square wave
y = y + square((Freq+beats)*2*pi*x);
y = y + square(Freq*2*pi*x); %square wave
y = y + square((Freq+beats)*2*pi*x);
T = 4;
overlay = Envelope(0.2,0.1,0.5,0.3,T,Fs);
y = overlayAmp(x,y,overlay,T,Fs);
f = Fs * (-Len/2 : (Len/2 - 1))/Len ;
Mod_Freq = fft(y);
figure(1)
plot(f, abs(fftshift(Mod_Freq)));
y = bandpassFilter(f,y,0,22000);
Mod_Freq = fft(y);
figure(2)
plot(f, abs(fftshift(Mod_Freq)));
T = 2;
overlayPitch = Envelope(0.4,0.1,0.9,0.3,T,Fs);
y = PitchEnvelope(f,y,1,overlayPitch,T,Fs,Time);
sound(y,Fs);
function output = bandpassFilter(F,y,LOW,HIGH)
Mod_Freq = fftshift(fft(y));
Mod_f = fftshift(fft(F));
lenf = length(F);
output = 0 .* Mod_f; % zero array of len f
for n = 1:lenf
if ((LOW < abs(F(n))) && HIGH > abs(F(n)))
output(n) = 1;
else
output(n) = 0;
end
end
filtered_Mod_Freq = fftshift(Mod_Freq .* output);
output = real(ifft(filtered_Mod_Freq));
end
function output = PitchEnvelope(f,y,percentile,shift,T,Fs,Time) %just need to change percentile to a graph
x = 0:1/Fs:Time;
leny = length(y); %create zero array of y of len x
lengthxol = T * Fs;
shift = 1 - shift;
for n = 1:leny
y(n) = y(n)*cos(shift(mod(n,lengthxol)+1)*2*pi*x(n));
end
Mod_Freq = fftshift(fft(y));
Mod_f = fftshift(fft(f));
lenf = length(f);
output = 0 .* Mod_f; % zero array of len f
midpoint = round(lenf/2);
Filtered_Signal = fftshift(fft(bandpassFilter(f,y,0,22000)));
filtered_Signal = real(ifft(Filtered_Signal));
demod_Signal = filtered_Signal .* 0; %create zero array of y of len filtersignal
for n = 1:leny
demod_Signal(n) = 2* filtered_Signal(n) *cos(shift(mod(n,lengthxol)+1)*2*pi*x(n));
end
Message = fftshift(fft(bandpassFilter(f,demod_Signal,-5000,5000)));
message = real(ifft(Message));
output = y;
end
function output = overlayAmp(x,y,overlay,T,Fs)
counter = 1;
lengthx = length(x);
lengthxol = T * Fs;
while counter < lengthx
y(counter) = y(counter) * overlay(mod(counter,lengthxol)+1);
counter = counter+1;
end
output = y;
end
function output = Envelope(attack,decay,sustain,release,T,Fs) %percentages for attack, decay, sustain, release
attacktime = attack * T * Fs;
decaytime = attacktime + decay * T * Fs;
sustaintime = (T - (release * T))* Fs;
x = 0:1/Fs:T;
y = 0 .* x; %create zero array of y of len x
tcounter = 1;
%attack phase
while tcounter <= attacktime
y(tcounter) = (1/attacktime) * tcounter;
tcounter = tcounter+1;
end
istart = tcounter;
while tcounter<= decaytime
y(tcounter) = 1 - (((1-sustain)/(decay * T * Fs)) * (tcounter - istart));
tcounter = tcounter+1;
end
while tcounter<= sustaintime
y(tcounter) = sustain;
tcounter = tcounter+1;
end
istart = tcounter;
while tcounter < (T * Fs)
y(tcounter) = sustain - ((sustain/(release * T * Fs)) * (tcounter - istart));
tcounter = tcounter+1;
end
plot(x,y)
output = y;
end

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%Written by Darell and Anne
%If there is a frequency of 200Hz:
%1. it needs to ramp up a frequency from 0Hz to the 200Hz over the attack time
%2. It needs to ramp down to a set sustained frequency over the decay time e.g. 160Hz < 200Hz
%3. It maintains this 160Hz until the release time
%4. Release time: It decays from 160Hz further all the way back to 0Hz.
% CONTRIBUTORS:
% Person1: Darell
% Person2: Anne
% DOCUMENTATION:
% phase shift is in number of periods
% fs is the sampling frequency: how many sample points per second
% duration is time in seconds
% duty is a number between 0 and 1
function output = DarellAnnePitchEnvelope(input, Fs, attack,decay,sustain,release) %percentages for attack, decay, sustain, release
len = length(input);
@ -54,4 +70,4 @@ function output = DarellAnnePitchEnvelope(input, Fs, attack,decay,sustain,releas
tcounter = tcounter+1;
end
end
end