[Optimization of the pseudorandom input signals used for the forced oscillation technique]

Area of Science:

• Pulmonary Physiology
• Biomedical Engineering
• Signal Processing

Context:

• The forced oscillation technique (FOT) is crucial for assessing respiratory mechanics.
• Current FOT methods use various excitation signals, including pseudorandom signals.
• Pseudorandom signals can suffer from time-domain amplitude overshoot, complicating data acquisition.

Purpose:

• To optimize the phase of pseudorandom signals used in FOT.
• To mitigate time-domain amplitude overshoot in combined multi-sinusoidal pseudorandom signals.
• To enhance the accuracy of respiratory system identification within the 4-40 Hz range.

Summary:

• This research investigated two phase optimization methods for pseudorandom signals: random phase combination and a time-frequency domain swapping algorithm.
• The time-frequency domain swapping algorithm demonstrated superior performance in optimizing signal phase, as measured by the crest factor.
• Amplitude compensation in the low-frequency band (4-18 Hz) was applied to meet specific respiratory system identification requirements.

Impact:

• The optimized pseudorandom signals, particularly those processed with the time-frequency domain swapping algorithm, are suitable for accurate respiratory system identification.
• This work provides a method to generate high-quality stimulus signals for pulmonary function testing.
• Improved signal characteristics can lead to more reliable assessments of respiratory mechanical properties.