Device for measuring sound waves emitted by sound-emitting device

A sound-measuring device for measuring an average amplitude of sound waves of a sound-emitting device, comprising:

• a sound-proof chamber configured to receive the sound-emitting device therein, the sound-proof chamber comprising a sound insulating film facing toward the sound-emitting device;
• an integration circuit;
• a laser diode;
• a driver configured to drive the laser diode to emit a laser beam;
• a storage unit configured to store a table;
• a light sensing unit;
• a first optical fiber having a first end optically coupled to the laser diode and an opposite second end;
• and
• a second optical fiber having a first end optically coupled to the light sensing unit and an opposite second end, the second end of the first optical fiber being placed on the sound insulating film and configured for optical alignment with the second end of the second optical fiber, the sound waves of the sound-emitting device causing the sound insulating film to vibrate thereby the vibration of the sound insulating film causing misalignment between the second end of the first optical fiber and the second end of the second optical fiber, the table recording the a mapping relationship between insertion loss values caused by the sound waves and average amplitudes of the sound waves;
• wherein the integration circuit is configured to calculate an insertion loss value between the portion of the laser beam and the laser beam from the laser diode, and determine an average amplitudes of the sound waves according to the table and the calculated insertion loss value.