Underwater Acoustic Projector Transducer Damping Circuit
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Solution Overview
Problem
Underwater sonar systems face interference from projectors reradiating and exciting resonance in hydrophones during the off cycle, causing signal distortion due to parasitic resonance from reflected waves.
Innovation Solution
Incorporating a drive circuit with two diodes and an electrical resistor to provide mechanical damping, converting electrical resistance to mechanical damping resistance, reducing parasitic resonance without affecting the transmitting response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the projector is turned off during receive mode, then the hydrophone can detect reflected signals, but the projector still excites resonance from reflected waves causing parasitic radiation and signal distortion
Solution Approach 1:
The patent converts the harmful reflected acoustic waves into a beneficial effect by using them to drive the damping circuit. The reflected waves that would normally excite parasitic resonance in the projector are instead used to generate electrical signals that are dissipated through the damping resistor, transforming the harmful mechanical resonance into useful electrical energy dissipation.
Solution Approach 2:
The patent introduces an electrical damping circuit as an intermediary between the projector's mechanical resonance and the hydrophone detection system. This circuit acts as a mediator that absorbs and dissipates the parasitic resonance energy through electrical resistance, preventing it from radiating acoustically while allowing the hydrophone to detect the original reflected signal.
2Volume of moving object
If the projector is placed close to hydrophones for compact sonar design, then device size is reduced, but the projector interferes with hydrophone reception during off cycle
Solution Approach 1:
The damping circuit converts the harmful close-proximity interference into a controllable electrical parameter. By transforming the mechanical resonance problem into an electrical damping problem, the system can maintain compact dimensions while the resistor dissipates the interference energy that would otherwise corrupt the hydrophone signal.
3Object-generated harmful factors
If electrical damping resistance is added to the projector circuit, then parasitic resonance is reduced, but circuit complexity increases
Solution Approach 1:
The patent extracts the damping function from the mechanical domain and places it in the electrical domain. By removing the need for complex mechanical damping structures and implementing damping through simple electrical resistance, the solution reduces overall system complexity while effectively suppressing parasitic resonance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces the projector's resonance output, minimizing interference with hydrophone reception and making the projector 'acoustically transparent' during receive mode.
Implementation Method 1
electro-mechanical transduction apparatus comprising: at least one hydrophone for detecting a reflected signal from a target; a projector for generating an acoustic signal
Implementation Method 2
two diodes and an electrical resistor to collectively provide a means for mechanically damping any mechanical resonance
Data Source
AI summary
An electro mechanical piezoelectric under water sound acoustic projector transducer which does not interfere with adjacent hydrophone reception and is mainly controlled at the electrical input is presented here. The method recognizes that the main interference with the adjacent hydrophone is mostly due to the resonance of the projector when not transmitting and is excited by the incoming acoustic wave reflected from the target signal originally initiated by the projector. Means for accomplishing this are shown to be simple to implement on current or new projector systems. The process uses an electrical resistor that absorbs the incoming acoustic wave as if the resistor were a mechanical damper and the projector transducer were acoustically transparent.