Application Cases

Experiment Name: Application of Power Amplifiers in Measuring the Angle of Arrival Resolution of Underwater Acoustic Signals Using a Self-Developed Receiver

Experimental Content:
Underwater acoustic signals cause changes in the refractive index of the medium during propagation. When a laser passes through an acoustically disturbed medium, the spatial variation in the refractive index induces deflection of the laser beam. A position-sensitive detector (PSD) is used to sense this deflection. The PSD contains four photodiodes that record light intensity parameters, and the X and Y positional shifts are calculated by adding and subtracting the four data points. Based on the laser position changes detected by the PSD, the acoustic signal information is reconstructed.

Research Direction: Acousto-Optic Sensing, Sound Field Reconstruction

Testing Equipment: ATA-4051 high-voltage power amplifier, self-developed acoustic signal receiver

Experimental Procedure:
The experimental system consists of a transmitter and a receiver. The transmitter generates a 75 kHz sinusoidal pulse signal, which is amplified by the Aigtek ATA-4051 high-voltage power amplifier before being applied to a CT75 transducer to emit underwater acoustic signals. At the receiving end, a self-developed acousto-optic sensing device is used to receive and measure the acoustic signals, calculating the angle of arrival of the acoustic wave.

Experimental Results:
The experimental results graphically display the direct measurements of micro-displacements on the PSD, achieving a resolution of approximately 0.2°. By applying a phase difference calculation formula to precisely compute the results shown in the left figure, the resolution of the angle of arrival measurement can be further improved, ultimately achieving an accuracy better than 0.015°.

Figure: ATA-4051C High-Voltage Power Amplifier Specifications and Parameters