/**
 * This interface defines several useful constants used throughout
 * the mobile client code for ultrasound detection.
 *
 * @author Tony Offer
 * @author Chris Palistrant
 * @version 1.0
 */
public interface Constants {
	// The sampling rate used for recording and used by the
	// ultrasound detection algorithm for various calculations.
	public static final float SAMPLING_RATE = 44100.0F;

	// A default target frequency for the ultrasound detection
	// algorithm.  The target frequency is the frequency that the
	// ultrasound detection algorithm looks for in the audio signal.
	public static final float TARGET_FREQUENCY = 21000.0F;

	// The block size used by the Goertzel algorithm.  This number
	// represents the amount of samples necessary to make a decision
	// as to the presence of the target frequency.
	public static final int N = 420;

	// The size, in bits, of the audio samples that will be recorded
	// while listening for ultrasound.  Note that reading from a
	// Java data line for the purposes of recording audio returns a
	// stream of bytes, which do not necessarily contain the same
	// number of bits as the samples themselves.
	public static final int SAMPLE_SIZE = 16;

	// The number of channels used to record ultrasound
        //public static int CHANNELS = 1;   // mono

	// Whether or not the recorded samples are signed.
	public static final boolean SIGN = true;

	// Whether or not the samples employ big endian encoding.
	public static final boolean BIGEND = false;

	// The threshold above which the magnitude returned by the
	// Goertzel algorithm for the target frequency is sufficient to
	// give a positive detection of the target frequency.
	public static final int THRESHOLD = 3500;
}