Student(s): Sophia Pham
Project: High-Frequency Acoustic Sensors for Joint Underwater Communication and Sensing | View Poster (PDF)
Major(s): Computer Engineering (Data Science and Music minors)
Advisor(s): Rosa Zheng
Abstract
Underwater acoustic communication experiences amplitude attenuation as a function of carrier frequency and communication distances. The higher the frequency, or the longer the distance, the higher the attenuation. However, it is desirable for the acoustic receiver to utilize a variable gain amplifier such that the received signal achieves similar amplitude after the Low Noise Amplifiers (LNA) when the received input signal has different strengths.
In this work, we first test a fixed-gain LNA for a carrier frequency of 115 kHz receiver and verify its frequency response and dynamic range of amplification. We then test a voltage controlled amplifier (VCA) for its capability of maintaining a fixed output amplitude at different input voltages. The VCA demonstrates the variable amplification gains given various input signals, relying on a controller to adjust the voltage supplied to the unit and therefore the amplification provided. The VCA outputs are then level shifted to 0 – 3.3 V before feeding to the analog to digital conversion (ADC). The VCA is shown to avoid overshoot and clipping of the signals when the inputs are strong, while providing large amplification gain when the signal is weak.
About Sophia Pham
Sophia Pham is a second-year student at Lehigh University, studying Computer Engineering with minors in Data Science and Music. She has been conducting research under Dr. Rosa Zheng throughout this Spring semester, working to implement dynamic receiver-side amplification to advance underwater communication testing across different environments. Previously, she was a Research Fellow through Lehigh’s Mountaintop program working on “STEM Visualizations,” a collection of learning modules featuring dynamic, interactive data visualizations. This summer, she will be continuing her research with Dr. Zheng with the support of the Clare Boothe Luce Research Fellowship.