Investigation of a Phase-Locked Loop Receiver for a Parametric Acoustic Receiving Array

摘要

This report describes the investigation of a phase-locked loop (PLL) demodulator considered for use with the parametric acoustic receiving array (PARRAY). The PARRAY as an acoustic sensor is explained and the effects of longitudinal transducer motion on the PARRAY are described. This transducer vibration produces intermodulation products between the desired acoustic signals and the vibration induced signals. Both theoretical analysis and experimental data showing that the PLL demodulator can reduce this intermodulation in a PARRAY are given. Comparison is made between theoretically predicted PLL intermodulation reduction and measurements taken with simulated PARRAY signals. Also, experimental data are described showing the operation of the demodulator with a PARRAY undergoing transducer vibration. (Author)