A new phase difference measurement algorithm for extreme frequency signals based on discrete time Fourier transform...

Area of Science:

• Vibration Engineering
• Signal Processing
• Measurement Science

Background:

• Traditional discrete time Fourier transform (DTFT) algorithms exhibit poor phase difference measurement accuracy for ultralow and adjacent Nyquist frequency signals.
• This limitation is prevalent in vibration engineering applications, impacting precise analysis.

Purpose of the Study:

• To enhance the accuracy of phase difference measurements for extreme frequency signals.
• To identify and mitigate the primary sources of error in existing DTFT algorithms for such signals.

Main Methods:

• Analysis of phase difference measurement errors in the DTFT algorithm, pinpointing negative frequency contribution as a key bias source.
• Development of a novel phase difference measurement algorithm based on DTFT, incorporating negative frequency contributions.
• Derivation of new phase difference calculation formulas tailored for various window functions.

Main Results:

• The proposed algorithm demonstrates superior inhibition of spectrum leakage compared to traditional DTFT methods.
• Higher accuracy in phase difference measurement for extreme frequency signals was achieved.
• Simulation and experimental validation confirmed the enhanced performance over existing DTFT algorithms.

Conclusions:

• The novel DTFT-based algorithm effectively addresses the limitations of traditional methods for measuring phase differences in extreme frequency signals.
• The findings offer a significant improvement for accurate signal analysis in vibration engineering and related fields.