Forming microphone using optical modulation principle - using acoustic signal for frequency modulation of laser signal

摘要

The microphone is formed using a solid state laser system (10) exhibiting frequency modulation in response to excess pressure. Acoustic waves are converted into an optical frequency-modulated signal, and combined with a reference laser signal, to provide an IF signal modulated in proportion to the acoustic frequency. Pref. the obtained IF signal is fed through an IF filter, and the reference laser signal and the optical fequency coded signal are both obtained from the same laser crystal. ADVANTAGE - Effective noise suppression, high bandwidth in infrared to ultrasonic spectrum, high dynamic range.