This paper presents a novel method for the analysis of heart rate variability (HRV) during exercise stress testing enhanced with respiratory information. The instantaneous frequency and power of the low frequency (LF) and high frequency (HF) bands of the HRV are estimated by parametric decomposition of the instantaneous autocorrelation function (ACF) as a sum of damped sinusoids. The instantane...

The frequency of a sinusoidal signal is a well defined quantity. However, often in practice, signals are not truly sinusoidal, or even aggregates of sinusoidal components. Nonstationary signals in particular do not lend themselves well to decomposition into sinusoidal components. For such signals, the notion of frequency loses its effectiveness, and one needs to use a parameter which accounts f...

PURPOSE To study the perceptual consequences of changes in parameters of vocoded speech in various reverberation conditions. METHOD The 3 controlled variables were number of vocoder bands, instantaneous frequency change rate, and reverberation conditions. The effects were quantified in terms of (a) nonsense words' recognition scores for young normal-hearing listeners, (b) ease of listening ba...

This paper demonstrates methods for the online optimization of assistive robotic devices such as powered prostheses, orthoses and exoskeletons. Our algorithms estimate the value of a physiological objective in real-time (with a body "in-the-loop") and use this information to identify optimal device parameters. To handle sensor data that are noisy and dynamically delayed, we rely on a combinatio...

The classic approach for estimating instantaneous parameters relies on using the Hilbert Transform (HT). The HT method extracts the instantaneous parameters by comparing the imaginary part with the real part of an analytical signal. The instantaneous parameters obtained this way are frequently contaminated by noises. Using the wavelet transform (WT), one can extract the instantaneous parameters...

Different phase-locked loop algorithms applied to three-phase grid voltages implement a closed control based on the Park transform obtain voltage instantaneous phase and frequency. When single-phase must be processed, one of inputs is generated by block that, starting from available voltage, computes an additional signal with same frequency ideally orthogonal it. This paper introduces novel met...