SLAA732A February   2017  – April 2021 PGA460 , PGA460-Q1

 

  1. 1Trademarks
  2. 2Overview
  3. 3External Performance Factors
    1. 3.1 Range Requirements
    2. 3.2 Detectable Target and Objects
    3. 3.3 Ambient Environment
  4. 4Component Selection
    1. 4.1 Sonar Configuration
    2. 4.2 Transducer Selection
    3. 4.3 Driver Selection
    4. 4.4 Passive Tuning
      1. 4.4.1 Impedance Gain-Phase Analyzer
      2. 4.4.2 Tuning Capacitor
      3. 4.4.3 Damping Resistor
      4. 4.4.4 Tunable Transformer
  5. 5PGA460 Parameters
    1. 5.1 Center Frequency
    2. 5.2 Pulse Count
    3. 5.3 Current Limit
    4. 5.4 Time-Varying Gain and Digital Gain
    5. 5.5 Threshold
  6. 6End-of-Line Calibration
    1. 6.1 Transducer Parameters
      1. 6.1.1 Optimal Frequency and Sound Pressure Level Measurements
        1. 6.1.1.1 Frequency Diagnostic Feature of PGA460
        2. 6.1.1.2 External Microphone
  7. 7Revision History

4.4.3 Damping Resistor

The damping resistor (RDAMP) is a resistor added in parallel to the transducer to help reduce the ringing-decay time without jeopardizing the driver strength to maximize long-range measurements. A damping resistor can benefit both the transformer driven and bridge driven modes as a bleed-out resistor immediately at post-excitation. The damping resistor has minute-loading effects on the transducer during the bursting and receive segments and therefore a damping resistor is recommended for any mono-static configuration. Because of the complexity and number of components at the transducer, optimizing the value of RDAMP is currently an arbitrary process of monitoring the decay profile by trial and error. Given that the value of RDAMP ranges from 500 Ω to 25 kΩ, TI recommends to use a potentiometer to sweep and fine-tune the value for the specific sensor, driver, and component combination.