TEST (LowPassFilterTest, WorksOnRepetitiveWaves) {
// make two sine waves, but this time, several seconds long
unsigned int samples = frameRate * 5;
KeyFinder::AudioData a;
a.setChannels(1);
a.setFrameRate(frameRate);
a.addToSampleCount(samples);
for (unsigned int i = 0; i < samples; i++) {
float sample = 0.0;
sample += sine_wave(i, highFrequency, frameRate, magnitude); // high freq
sample += sine_wave(i, lowFrequency, frameRate, magnitude); // low freq
a.setSample(i, sample);
// ensure repetition of sine waves is perfect...
if (i >= frameRate) {
ASSERT_NEAR(a.getSample(i), a.getSample(i - frameRate), tolerance);
}
}
KeyFinder::LowPassFilter* lpf = new KeyFinder::LowPassFilter(filterOrder, frameRate, cornerFrequency, filterFFT);
KeyFinder::Workspace w;
lpf->filter(a, w);
delete lpf;
// test for lower wave only
for (unsigned int i = 0; i < samples; i++) {
float expected = sine_wave(i, lowFrequency, frameRate, magnitude);
ASSERT_NEAR(expected, a.getSample(i), tolerance);
}
}
static void busy_fill(short int *p, int size)
{
/* variables */
long int sig_600; /* value of the 600 Hz tone signal */
long int sig_120; /* value of the 120 Hz modulating signal */
long int angle; /* angle to find the sine for */
int i; /* general loop index */
/* fill the buffer with data */
for (i = 0; i < size; i++) {
/* check if past the end of the tone + silent portion */
if (++ring_busy_timer >= (BUSY_TONE_TIME + BUSY_SILENT_TIME))
/* timer has wrapped, reset it */
ring_busy_timer = 0;
/* get the angle for both waveforms (with a factor of 5) */
/* calculation is complicated to keep it from overflowing */
angle = (((600 * ring_busy_timer) / SAMPLE_RATE) * SINE_RESOLUTION) +
(((600 * ring_busy_timer) % SAMPLE_RATE) * SINE_RESOLUTION) / SAMPLE_RATE;
/* get the 600 Hz sine wave */
sig_600 = sine_wave(angle);
/* now get the 120 Hz modulation wave (5 = 600 Hz / 120 Hz) */
sig_120 = sine_wave(angle / 5);
/* the modulation signal should always be positive */
if (sig_120 < 0)
sig_120 = -sig_120;
/* should the tone be output or should it be silent */
if (ring_busy_timer < BUSY_TONE_TIME)
/* outputting the tone (make it -13 dBm) */
p[i] = (sig_600 * sig_120) / (4096 * 4);
else
/* output no tone - store a 0 */
p[i] = 0;
}
/* all done filling the buffer - return */
return;
}
TEST (LowPassFilterTest, MaintainsLowerFreqs) {
// make a low frequency sine wave, one second long
KeyFinder::AudioData a;
a.setChannels(1);
a.setFrameRate(frameRate);
a.addToSampleCount(frameRate);
for (unsigned int i = 0; i < frameRate; i++) {
a.setSample(i, sine_wave(i, lowFrequency, frameRate, magnitude));
}
KeyFinder::LowPassFilter* lpf = new KeyFinder::LowPassFilter(filterOrder, frameRate, cornerFrequency, filterFFT);
KeyFinder::Workspace w;
lpf->filter(a, w);
delete lpf;
// test for near perfect reproduction
for (unsigned int i = 0; i < frameRate; i++) {
float expected = sine_wave(i, lowFrequency, frameRate, magnitude);
ASSERT_NEAR(expected, a.getSample(i), tolerance);
}
}
TEST (LowPassFilterTest, DoesBothAtOnce) {
// make two sine waves, one second long
KeyFinder::AudioData a;
a.setChannels(1);
a.setFrameRate(frameRate);
a.addToSampleCount(frameRate);
for (unsigned int i = 0; i < frameRate; i++) {
float sample = 0.0;
sample += sine_wave(i, highFrequency, frameRate, magnitude); // high freq
sample += sine_wave(i, lowFrequency, frameRate, magnitude); // low freq
a.setSample(i, sample);
}
KeyFinder::LowPassFilter* lpf = new KeyFinder::LowPassFilter(filterOrder, frameRate, cornerFrequency, filterFFT);
KeyFinder::Workspace w;
lpf->filter(a, w);
delete lpf;
// test for lower wave only
for (unsigned int i = 0; i < frameRate; i++) {
float expected = sine_wave(i, lowFrequency, frameRate, magnitude);
ASSERT_NEAR(expected, a.getSample(i), tolerance);
}
}
TEST (AudioDataTest, DownsamplerResamplesSineWave) {
unsigned int frameRate = 10000;
unsigned int frames = frameRate * 4;
float freq = 20;
float magnitude = 32768.0;
unsigned int factor = 5;
KeyFinder::AudioData a;
a.setChannels(1);
a.setFrameRate(frameRate);
a.addToSampleCount(frames);
for (unsigned int i = 0; i < frames; i++)
a.setSample(i, sine_wave(i, freq, frameRate, magnitude));
a.downsample(factor);
unsigned int newFrameRate = frameRate / factor;
unsigned int newFrames = frames / factor;
ASSERT_EQ(newFrameRate, a.getFrameRate());
ASSERT_EQ(newFrames, a.getSampleCount());
for (unsigned int i = 0; i < newFrames; i++)
ASSERT_NEAR(sine_wave(i, freq, newFrameRate, magnitude), a.getSample(i), magnitude * 0.05);
}
TEST (LowPassFilterTest, KillsHigherFreqs) {
// make a high frequency sine wave, one second long
KeyFinder::AudioData a;
a.setChannels(1);
a.setFrameRate(frameRate);
a.addToSampleCount(frameRate);
for (unsigned int i = 0; i < frameRate; i++) {
a.setSample(i, sine_wave(i, highFrequency, frameRate, magnitude));
}
KeyFinder::LowPassFilter* lpf = new KeyFinder::LowPassFilter(filterOrder, frameRate, cornerFrequency, filterFFT);
KeyFinder::Workspace w;
lpf->filter(a, w);
delete lpf;
// test for near silence
for (unsigned int i = 0; i < frameRate; i++) {
ASSERT_NEAR(0.0, a.getSample(i), tolerance);
}
}
playSineWave(unsigned int freq){
sn=3;
sine_wave(freq);
}
