Crest factor optimization of the multisine waveform for bioimpedance spectroscopy

Area of Science:

• Electrical Engineering
• Measurement Science

Background:

• Multisine excitation is preferred for impedance measurements, balancing sine wave benefits with reduced time.
• Maintaining low signal amplitude is essential for linearity assumption, necessitating crest factor (CF) minimization.

Purpose of the Study:

• To introduce a novel empirical method for minimizing the crest factor (CF) of multisine excitation signals.
• To ensure the computed CF approaches the global minimum through systematic parameter variation.
• To investigate the impact of phase accuracy and frequency distribution on CF.

Main Methods:

• A novel empirical algorithm for crest factor minimization is presented.
• A sparing algorithm facilitates systematic variation of initial parameters to find near-global minimum CF.
• The influence of phase accuracy is analyzed, and a phase recalculation algorithm is described.
• Comparisons of CF across different frequency distributions are performed.

Main Results:

• The novel method achieves near-global minimum CF values, often matching or exceeding other methods.
• A method for recalculating optimal phases to a coarser resolution is developed, preserving minimal CF.
• Results demonstrate that minimal CF can be maintained even with rough phase resolutions.
• Comparison of CF across various frequency distributions is provided.

Conclusions:

• The developed empirical method effectively minimizes the crest factor for multisine signals.
• Practical implementation is enhanced through phase recalculation, maintaining high optimization results.
• The findings contribute to more accurate and efficient impedance measurements using multisine excitation.