Characteristics of Vibration Masking System against Acoustic Signal Restoring

The non-contact measurement that can restore the speech information by recording the voice-induced vibration on the surface of the objects is one method of signal restoring. And vibration masking is an effective way against signal restoring by non-contact measurement. Aiming at vibration masking system against acoustic signal restoring, in this paper, we analyze the vibration characteristics on surface of glass, then a vibration propagation decay model on surface of square glass is proposed. The relationship between the vibration intensity caused by speech and the intensity of the sound source is measured. Also, the relationship between vibration intensity produced by vibration converter and the sound pressure emitted from vibration converter is tested. The results show that the masking effect performs well when the vibration generated by the vibration converter is 15dB higher than the vibration caused by the speech.