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Fix #1817 fourier transform for built in mic input working fine #1830

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Merged
merged 2 commits into from
Jun 25, 2019
Merged

Fix #1817 fourier transform for built in mic input working fine #1830

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a384577
fourier transform for built in mic input working fine
neel1998 Jun 25, 2019
b3be49c
debugging statement removed
neel1998 Jun 25, 2019
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50 changes: 43 additions & 7 deletions app/src/main/java/io/pslab/activity/OscilloscopeActivity.java
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Original file line number Diff line number Diff line change
Expand Up @@ -471,11 +471,9 @@ public void run() {
}
}

if (!isInBuiltMicSelected) {
if (audioJack != null) {
audioJack.release();
audioJack = null;
}
if (!isInBuiltMicSelected && audioJack != null) {
audioJack.release();
audioJack = null;
}
}
}
Expand Down Expand Up @@ -794,6 +792,10 @@ protected void onDestroy() {
recordTimer.cancel();
recordTimer = null;
}
if (audioJack != null) {
audioJack.release();
audioJack = null;
}
super.onDestroy();
}

Expand Down Expand Up @@ -1011,11 +1013,39 @@ protected Void doInBackground(String... channels) {
}
short[] buffer = audioJack.read();
yDataString.add(new String[buffer.length]);
for (int i = 0; i < buffer.length; i++) {

int n = buffer.length;
Complex[] fftOut = null;
if (isFourierTransformSelected) {
Complex[] yComplex = new Complex[n];
for (int j = 0; j < n; j++) {
float audioValue = (float) map(buffer[j], -32768, 32767, -3, 3);
yComplex[j] = Complex.valueOf(audioValue);
}
fftOut = fft(yComplex);
}
double factor = buffer.length * timeGap * 1e-3;
maxFreq = (n / 2 - 1) / factor;
double mA = 0;
for (int i = 0; i < n; i++) {
float audioValue = (float) map(buffer[i], -32768, 32767, -3, 3);
if (!isFourierTransformSelected) {
entries.get(noOfChannels - 1).add(new Entry(i, audioValue));
} else {
if (i < n / 2) {
float y = (float) fftOut[i].abs() / samples;
if (y > mA) {
mA = y;
}
entries.get(noOfChannels - 1).add(new Entry((float) (i / factor), y));
}
}
yDataString.get(noOfChannels - 1)[i] = String.valueOf(audioValue);
entries.get(noOfChannels - 1).add(new Entry(i, audioValue));
}
if (mA > maxAmp) {
maxAmp = mA;
}

}
if (isRecording) {
loggingXdata = String.join(" ", xDataString);
Expand Down Expand Up @@ -1175,6 +1205,12 @@ public Complex[] fft(Complex[] input) {
for (int k = 0; k < n / 2; k++) {
double kth = -2 * k * Math.PI / n;
Complex wk = new Complex(Math.cos(kth), Math.sin(kth));
if (r[k] == null) {
r[k] = new Complex(1);
}
if (q[k] == null) {
q[k] = new Complex(1);
}
y[k] = q[k].add(wk.multiply(r[k]));
y[k + n / 2] = q[k].subtract(wk.multiply(r[k]));
}
Expand Down