问题
I am using this code https://stackoverflow.com/questions/23432398/audio-recorder-in-android-process-the-audio-bytes to capture the mic audio but I am writing the data to a ByteArrayOutputStream. After I finish the record I want to demodule the signal captured by using Goertzel Algorithm. The FSK signal consists out of 2 frequencies, 800Hz for '1' and 400Hz for '0' each bit is moduled using 100 samples. I am using this class of Goertzel: http://courses.cs.washington.edu/courses/cse477/projectwebs04sp/cse477m/code/public/Goertzel.java I am trying to use a bin size of 150.
Here is what I try to do: the code, after I finish the recording:
private void stopRecording()
{
if(recorder != null)
{
isRecording= false;
recorder.stop();
recorder.release();
recorder = null;
recordingThread = null;
int BlockSize = 150;
float HighToneFrequency = 800;
float LowToneFrequency = 400;
byte[] byteArrayData = ByteArrayAudioData.toByteArray();
/*final AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
8000, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, byteArrayData.length,
AudioTrack.MODE_STATIC);
audioTrack.write(byteArrayData, 0, byteArrayData.length);
audioTrack.play();*/
double[] daOriginalSine = convertSample2Sine(byteArrayData);
int i = 0;
while(i < daOriginalSine.length)
{
double t1 = testSpecificFrequency(i, HighToneFrequency,BlockSize, daOriginalSine);
double t2 = testSpecificFrequency(i, LowToneFrequency,BlockSize, daOriginalSine);
i+=BlockSize;
}
}
}
And the function testSpecificFrequency:
private double testSpecificFrequency(int startIndex, float ToneFreq, int BlockSize, double[] sample)
{
Goertzel g = new Goertzel(RECORDER_SAMPLERATE, ToneFreq, BlockSize, false);
g.initGoertzel();
for(int j=startIndex ; j<startIndex+BlockSize ; j++)
{
g.processSample(sample[j]);
}
double res= Math.sqrt(g.getMagnitudeSquared());
return res;
}
I just tried to see what will be the results, by sending 800Hz to the constructor and afterwars sending 400Hz,don't really know how to proceed from this point =\
Any ideas?
来源:https://stackoverflow.com/questions/29049981/android-demod-fsk-using-goertzel