Banca de DEFESA: EVELYN CRISTINA DE OLIVEIRA LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EVELYN CRISTINA DE OLIVEIRA LIMA
DATE: 15/03/2023
TIME: 09:00
LOCAL: meet.google.com/ovb-ddmb-trg
TITLE:

PROGRAMMABLE BANDPASS SIGMA-DELTA MODULATORS USING N-PATH FILTERS

KEY WORDS:

Sigma-Delta, N-Path Filter, LC Filter, AD Converters

PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Medidas Elétricas, Magnéticas e Eletrônicas; Instrumentação
SPECIALTY: Instrumentação Eletrônica
SUMMARY:

In Software Defined Radio (SDR) most analog functions such as downconversion and channel selection are moved into the digital domain. With these features, an SDR can be easily programmed and adapted to new standards. However, its implementation using a Nyquist rate analog-to-digital converter (ADC) has been challenging and very power-hungry, which makes it unsuitable for mobile applications. SDM (Sigma-Delta Modulator) using LC resonators are well suited for this purpose, as they can convert a narrowband around a radio frequency (RF) center frequency. In the literature, high-order LC-based SDM uses nodes between LC tanks for feedforward or feedback coefficients, to obtain the desired noise transfer function (NTF). These nodes are often an additional source of noise, non-linearity, and power consumption, affecting overall SDM performance. In this project, we aim to explore the functionality of N-Path filters to implement a programmable Sigma-Delta Bandpass Modulator that meets various communication standards. Therefore, it was necessary to carry out a bibliographic and technological research on the state of the art of N-path filters, continuous-time and discrete-time Sigma-Delta modulators. There was also the development of high-level models for different topology categories of Sigma-Delta Modulators implemented with LC and discrete-time filters to serve as comparison models with the topology design methodology using the N-path filter proposed in this work. A high-level model of the N-Path filter was developed, and the work is currently in the stage of integrating the N-path filter and SDM. The results obtained from the SDM implementation with LC filters show that the modulator has a good agreement with its DT equivalent. In initial experiments, the implementation of SDM with an RLC circuit equivalent to the N-path filter proved to be promising, presenting results similar to those obtained with the discrete-time topology.

COMMITTEE MEMBERS:
Presidente - 2140683 - DIOMADSON RODRIGUES BELFORT
Interno - 1284113 - SEBASTIAN YURI CAVALCANTI CATUNDA
Externo à Instituição - FRANCISCO DE ASSIS BRITO FILHO - UFERSA