Wideband Sonar Transmitter Pulse Compression and Transformer Design
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Solution Overview
Problem
Conventional sonar systems face challenges in achieving frequency-agile performance and high power at a low cost, particularly in wideband applications where transformers must balance conflicting demands of low frequency and high frequency operations, leading to issues with insertion loss and heating effects.
Innovation Solution
A digital logic-controlled sonar transmitter using pulse width modulation to approximate sinusoidal waveforms with MOSFET switches and a center-tapped transformer, coupled with a boost control circuit and a novel wideband isolating transformer design that minimizes leakage inductance, enabling efficient power delivery across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transformer is used to isolate and impedance match the transducer to the amplifier, then the transducer is isolated and impedance matched, but insertion loss increases and heating effects occur due to coupling between transformer windings and parasitics
Solution Approach 1:
The patent extracts the parasitic elements (leakage inductance and winding capacitance) from the transformer model and creates separate compensation circuits for them. The leakage inductance is compensated by adding series inductors, and the winding capacitance is compensated by adding parallel capacitors, thereby removing their harmful effects on insertion loss while maintaining the transformer's isolation and impedance matching functions.
Solution Approach 2:
The patent changes the electrical parameters of the transformer circuit by adding compensating inductors and capacitors. These components adjust the overall inductance and capacitance values to counterbalance the parasitic elements, optimizing the impedance matching and reducing insertion loss across the operating frequency range.
2Power
If a linear power amplifier is used to provide high power over a wideband frequency range, then high power output is achieved, but the cost increases
Solution Approach 1:
The patent replaces the mechanical/analog linear power amplifier system with a digital signal processing approach. By using digital pulse compression and sophisticated signal processing techniques, the system achieves high power output and wideband performance without requiring an expensive linear power amplifier, thereby reducing cost while maintaining performance.
Solution Approach 2:
The patent changes the approach to power amplification by using digital signal processing and pulse compression techniques instead of a linear power amplifier. This allows the system to achieve high power output over a wideband frequency range through signal processing rather than through expensive analog amplification hardware.
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
The solution achieves high efficiency and cost-effectiveness by approximating sinusoidal waveforms through pulse width modulation, reducing the need for heat sinks and heavy, expensive components, while the transformer design maintains low leakage inductance for optimal wideband performance.
Implementation Method 1
In a conventional sonar, the power amplifier drives a transducer through a transformer. The transformer isolates the transducer and also functions to impedance match the transducer to the amplifier.
Implementation Method 2
A digital logic-controlled sonar transmitter using pulse width modulation to approximate sinusoidal waveforms with MOSFET switches and a center-tapped transformer
Implementation Method 3
a power amplifier drives a transducer
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A sonar transmitter includes digital logic that controls switches coupled to a primary coil of a transformer. The switches are driven to produce at least one voltage pulse across a secondary coil for the transformer to produce a series of voltage pulses approximating the desired signal. The transformer may comprise: a secondary coil having a plurality of windings arranged into a first section, a middle section, and a final section; and a primary coil winding wound only with the secondary coil windings forming the middle section.