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Optimization of a digital lock-in algorithm with a square-wave reference for frequency-divided multi-channel sensor

Shengzhao Zhang1, Gang Li1, Ling Lin1

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This study optimizes digital lock-in detection using square wave references for multi-channel sensor signals. Proper filter and carrier frequency settings eliminate channel interference, enhancing accuracy and efficiency.

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Area of Science:

  • Signal processing
  • Measurement science

Background:

  • Digital lock-in detection measures signal amplitude and phase.
  • Square wave references offer implementation and computational advantages over sinusoidal waves.
  • Demodulating multi-frequency signals with square waves can cause channel interference.

Purpose of the Study:

  • To modify digital lock-in detection calculations for multi-channel signals.
  • To optimize low-pass filter and carrier frequency parameters.
  • To eliminate channel interference and reduce computational complexity.

Main Methods:

  • Modified calculation methods for digital lock-in detection.
  • Analysis of optimal low-pass filter length and carrier frequencies.
  • Implementation of square wave reference for demodulation.

Main Results:

  • Optimized parameters successfully removed interference between channels.
  • Achieved accurate measurement of multi-channel sensor signals.
  • Demonstrated improved computational efficiency compared to traditional methods.

Conclusions:

  • Optimized digital lock-in detection with square wave references is suitable for multi-channel sensor measurements.
  • Proper parameter tuning is crucial for avoiding channel interference.
  • This technique enhances accuracy and efficiency in complex signal analysis.