The aim of this thesis is to present a phase-hopping frequency synthesizer using a Rotary Traveling Wave Oscillator (RTWO), as well as the benefits and limitations of physical realizations. The RTWO is a novel approach to Integrated Circuit (IC) Voltage Controlled Oscillator (VCO) design that employs a differential transmission line terminated on itself in a manner similar to a Möbius strip. Be...

In this paper, we address the issue of how the perception of disorderness in selected types of speech disorders may be correlated with the abnormal articulatory structure and with the related acoustic properties. As a first step towards this end we have developed an articulatory synthesizer based on frequency-domain simulation of vocal-tract wave propagation. The synthesizer has been implemente...

This thesis consists of six publications and an overview of the research topic, which is also a summary of the work. The research described in this thesis concentrates on the design of phase-locked loop radio frequency synthesizers for wireless applications. In particular, the focus is on the implementation of the prescaler, the phase detector, and the chargepump. This work reviews the requirem...

This paper discusses a hybrid audio synthesis method employing both additive synthesis and DPCM audio playback, and the implementation of a miniature synthesizer system that accepts MIDI as an input format. Additive synthesis is performed in the frequency domain using a weighted overlap-add filterbank, providing efficiency gains compared to previously known methods. The synthesizer system is im...

DDFS (Direct Digital Frequency Synthesizer) is a new technique of frequency synthesizes which introduces the advanced digital processing theory into frequency synthesis. A direct digital frequency synthesizer is composed of a phase accumulator, an adder, an ROM for wave pattern saving, a D/A converter and a LPF (low pass filter). With the rapid development of VLSI, the speed of algorithm is req...