SLOA341 October   2024 LOG300

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Description
    1. 2.1 Basics of Ultrasound Sensing
    2. 2.2 Advantages and Disadvantages of Ultrasonic Sensing
    3. 2.3 Ultrasonic Transducer
      1. 2.3.1 Transducer Construction
      2. 2.3.2 Transducer Frequencies
    4. 2.4 Transducer Topologies
    5. 2.5 Blind Zone Effect on Minimum Distance
    6. 2.6 Transducer Drive
    7. 2.7 Ultrasonic Echo and Signal Processing
      1. 2.7.1 Digital Gain or Fixed Gain
      2. 2.7.2 Time-Varying-Gain
      3. 2.7.3 Automatic Gain Control or Logarithmic Amplifier
      4. 2.7.4 Logarithmic Amplifier vs Logarithmic Detector
  6. 3LOG Detector Amplifier and the Advantages Over Conventional Opamps
  7. 4Application
    1. 4.1 Double Paper Feed and Paper Thickness Detector
      1. 4.1.1 Schematic Implementation
      2. 4.1.2 Material Thickness Detector
    2. 4.2 Bubble Detector
    3. 4.3 Material Detection
    4. 4.4 Distance or Proximity Detection
  8. 5Summary
  9. 6References

1 Introduction

Ultrasonic sensing is a technology that utilizes high-frequency sound waves to detect objects and measure distances. This method is widely used in various applications, including industrial automation, automotive systems, and medical. Ultrasonic sensors emit sound waves at frequencies above the human hearing range (typically above 20kHz). The system mainly constitutes of two parts transmit and receive. Driving an ultrasonic transducer can be done in mainly two ways, either by transformer where higher excitation signal is required or directly using H-bridge or an amplifier where comparatively lower excitation is required. Whereas on receive side, there are different types of gain amplifier which can be used for signal processing like fixed gain, variable gain, time varying gain or a logarithmic (log) gain amplifier. This article demonstrates how a log detector can be incorporated in ultrasonic sensing systems to enhance the dynamic range and sensitivity. By using a logarithmic detector, ultrasonic sensing systems can effectively handle weak echoes and strong signals alike, making sure reliable and accurate measurements.