Check for echoes.

Author

Karin Fisch, Jan Benda

Version

1.2 (May 10, 2017)

Repeatedly play a signal with an triangular amplitude modulation and average the voltage output of a microphone. The averaged sound is then plotted as a function of distance the sound must have travelled. This way echos can be inspected.

Options

• duration=10ms: Stimulus duration (number)
• frequency=0kHz: Carrier frequency (number)
• intensity=80dB: Stimulus intensity (number)
• repeats=0: Repetitions of stimulus (integer)
• pause=100ms: Duration of pause between stimuli (number)
• outtrace=Left-Speaker: Output trace (string)
• intrace=Sound-1: Input trace (string)
• average=10: Number of trials to be averages (integer)
• maxecho=10m: Maximum echo distance (number)
• soundspeed=343m/s: Speed of sound (number)

Plot

The plot shows the averaged sound (orange) recorded by the microphone as a function of distance the sound must have travelled. The x-axis is shifted such that the peak of the triangular sound pulse indicates the distances. Without any delays the peak amplitude of the recorded sound will sit at distance zero (not the beginning of the sound pulse).

For orientation the original sound pulse is plotted in yellow at the position of the largest peak.