The ASP consists of several components: a digital beat-frequency oscillator (BFO), selectable band-pass filters for CW, SSB and other digital modes, a denoiser based on the least-mean-squares (LMS) technique and a Wiener-filter autonotcher (removing carriers or heterodynes). Several advanced concepts are applied in this project, such as multirate processing, adaptive filtering and frequency shi...

Monitoring the respiratory rate (RR) in a fast, inexpensive and continuous manner is of great interest as its direct measurement requires bulky, expensive and inconvenient equipment. In this study, the RR is estimated in an instantaneous manner from the electrocardiogram (ECG) using two ECG-derived respiratory waveforms: the respiratory sinus arrhythmia (RSA) and the modulation of R-peak amplit...

Oscillator Architectures and Enhanced Frequency Synthesizer. (December 2009) Sang Wook Park, B.S., Yonsei University, Korea; M.S., Yonsei University, Korea Chair of Advisory Committee: Dr. Edgar Sánchez-Sinencio A voltage controlled oscillator (VCO) that generates a periodic signal whose frequency is tuned by a voltage is a key building block in any integrated circuit system. A sine wave oscill...

A CMOS three-stage ring oscillator is examined in UMC 0.13 μm and 0.18 μm technologies. The influence of PMOS transistor and resistor, as inverter feedbacks, on the ring oscillator frequency and the peak-to-peak amplitude is investigated in both technologies. Furthermore, as the ring oscillator usually drives a buffer in pulse generator/transmitter chain, dependence of its Figures of Merit on t...

This manuscript presents the designing and investigative aspects of a low power, wide frequency range, and delay cell based 3 and 5-stage ring oscillator for RF-Ultra-WideBand application. The wide range of frequency is achieved by using two variable voltage sources i.e. control voltage source (Vcntrl) and tail current source (Vtail). A tail current improvement is responsible to control the cha...

Heart chaotic system and the ability of particle swarm optimization (PSO) method motivated us to benefit the method of chaotic particle swarm optimization (CPSO) to synchronize the heart three-oscillator model. It can be a suitable algorithm for strengthening the controller in presence of unknown parameters. In this paper we apply adaptive control (AC) on heart delay model, also examine the sys...

We present a control method for a simple limit-cycle bipedal walker that uses adaptive frequency oscillators (AFO’s) to generate stable gaits. Existence of stable limit cycles is demonstrated with an inverted-pendulum model. This model predicts a proportional relationship between hip torque amplitude and stride frequency. The closed-loop walking control incorporates adaptive Fourier analysis to...

An oscillator whose frequency is amplitude dependent can be controlled by a drive whose frequency sweeps through a resonance with the oscillator's fundamental frequency. This phenomenon is called autoresonance, and has been previously investigated for drives with frequencies near the oscillator's fundamental or subharmonic frequencies. This paper examines autoresonance for drives at twice the f...