Reorganized Into Folders

src/PitchEnvelope/DarellAnnePitchEnvelope.m

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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. 
+%This envelope uses logarithmic calculations
+
+% 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);
+    T = (len-1)/Fs;
+    attacktime = attack * T * Fs;
+    decaytime = attacktime + decay * T * Fs;
+    sustaintime = (T - (release * T)) * Fs;
+    
+    output =  zeros([1,len]); 
+    
+    tcounter = 1;
+    %attack phase
+    curr = attacktime;
+    while tcounter <= curr
+        ncount = round(curr*log(tcounter)/log(curr)+1);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+    
+    %decay phase
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = decaytime;
+    while tcounter <= curr
+        ncount = round(sustain*curr*(1-log(tcounter)/log(prevcur)) + prevcur);
+        tcounter = round(tcounter);
+        output(tcounter)
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+    
+    %sustain phase
+    prevncount = ncount;
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = sustaintime;
+    while tcounter <= curr
+        ncount = round(sustain*(tcounter - prevcur) + prevncount);
+        tcounter = round(tcounter);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+
+    %release phase
+    prevncount = ncount;
+    prevcur = curr;
+    tcounter = prevcur;
+    curr = Fs;
+    while tcounter <= Fs
+        ncount = round(curr*(1-log(tcounter)/log(prevcur)) + prevncount);
+        tcounter = round(tcounter);
+        output(tcounter) = input(ncount);
+        tcounter = tcounter+1;
+    end
+
+end