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Construction and Characterization of External Cavity Diode Lasers for Atomic Physics

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Published on: April 24, 2014

A method to remove odd harmonic interferences in square wave reference digital lock-in amplifier.

Gang Li¹, Shengzhao Zhang, Mei Zhou

¹State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin 300072, People's Republic of China.

The Review of Scientific Instruments

|March 8, 2013

Summary

This summary is machine-generated.

A new digital lock-in algorithm using a square wave reference effectively removes odd harmonic interferences. This method also detects interference amplitudes and phases, enhancing weak signal detection.

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Area of Science:

Electrical Engineering
Signal Processing

Background:

Digital lock-in amplifiers (DLIA) are crucial for signal processing.
Square wave reference DLIA are simpler to implement than sinusoidal ones.
Conventional algorithms struggle to remove odd harmonic interferences present in square wave references.

Purpose of the Study:

To introduce a novel square wave digital lock-in algorithm.
To address the limitation of removing odd harmonic interferences in DLIA.
To enable detection of interference amplitudes and phases.

Main Methods:

Development of a new square wave digital lock-in algorithm.
Simultaneous calculation of real and imaginary parts for the frequency component of interest and odd harmonic interferences.
Algorithm validation through simulation experiments.

Main Results:

The proposed algorithm successfully removes odd harmonic interferences.
The algorithm accurately detects the amplitudes and phases of these interferences.
Simulation results confirm the feasibility and effectiveness of the new algorithm.

Conclusions:

The novel square wave digital lock-in algorithm effectively overcomes limitations of conventional methods.
It enables simultaneous detection of signal components and harmonic interferences.
The algorithm's computational efficiency makes it suitable for weak signal detection on microprocessors.