// Handles the subscriber's NewMeasurements event.
private void DataSubscriber_NewMeasurements(object sender, EventArgs <ICollection <IMeasurement> > e)
{
// Gather statistics.
Interlocked.Add(ref m_measurementCount, e.Argument.Count);
// Queue the measurements up in the buffer.
foreach (IMeasurement measurement in e.Argument)
{
if (m_channelIndexes.ContainsKey(measurement.ID))
{
// Perform a rough per signal upsample if minimum sample rate is not met
if (m_sampleRate < MINIMUM_SAMPLE_RATE)
{
IMeasurement upsampledMeasurement;
double frequency = measurement.Value;
for (int i = 0; i < MINIMUM_SAMPLE_RATE / m_sampleRate; i++)
{
upsampledMeasurement = Measurement.Clone(measurement);
upsampledMeasurement.Value = Timbre.PureTone(frequency, i, 0, MINIMUM_SAMPLE_RATE) * Damping.Natural(i, MINIMUM_SAMPLE_RATE / m_sampleRate, MINIMUM_SAMPLE_RATE) * (Int16.MaxValue * 0.90D);
m_buffer.Enqueue(upsampledMeasurement);
}
}
else
{
m_buffer.Enqueue(measurement);
}
}
}
// If we've managed to buffer a full second of data,
// stop the timeout timer and start the dump timer.
// The dump timer is sending measurements to the sound card
// so change the playback state to playing.
if (m_dumpTimer != null && !m_dumpTimer.IsRunning && m_buffer.Count / 2 > m_sampleRate)
{
if (m_timeoutTimer != null)
{
m_timeoutTimer.Stop();
}
m_dumpTimer.Start();
OnStateChanged(PlaybackState.Playing);
}
}
// Static Methods
/// <summary>
/// Computes a dual-tone multi-frequency sound for the given <see cref="DTMF"/> information and time.
/// </summary>
/// <param name="tone">Instance of the <see cref="DTMF"/> specifying the duration as well as the low and high frequencies of the dual-tone.</param>
/// <param name="sampleIndex">Sample index (represents time anywhere from zero to full length of tone).</param>
/// <param name="sampleRate">Number of samples per second.</param>
/// <returns>The amplitude for the dual-tone at the given time.</returns>
/// <remarks>
/// This method computes an amplitude representing the acoustic pressure of a
/// <see cref="DTMF"/> of the given frequency for the given time.
/// </remarks>
public static double ComputeFrequencies(DTMF tone, long sampleIndex, int sampleRate)
{
return((Timbre.PureTone(tone.LowFrequency, sampleIndex, 0, sampleRate) + Timbre.PureTone(tone.HighFrequency, sampleIndex, 0, sampleRate)) / 2);
}
