Class D Audio Amplifier

The purpose of this project was to design and produce a 90% efficient, 80W Class D audio amplifier, with less than 1% Total Harmonic Distortion (THD) for the NECAMSID Lab. The amplifier consisted of a second order, three-level ∆Σ modulator, an H-bridge power stage, and a second order, passive Butterworth filter. Testing confirmed that the efficiency, THD, and power specifications were met in the final revision of the design

Reproducing single-carrier digital modulation schemes for VLC by controlling the first switching harmonic of the dc-dc power converter output voltage ripple

A DC-DC power converter based on a two-phase synchronous buck converter that reproduces single-carrier digital modulation schemes by controlling the first switching harmonic of the output voltage ripple is presented in this work. The DC-DC power converter carries out both the lighting and the transmission functionalities of Visible Light Communication (VLC) transmitters. Control of both the amplitude and the phase of sinusoidal currents injected towards High-Brightness LEDs (HB-LEDs) enables the use of efficient modulation schemes such as Quadrature Amplitude Modulation (QAM), Carrier-less Amplitude and Phase modulation (CAP), Amplitude-Shift Keying (ASK) and Phase-Shift Keying (PSK). These modulation schemes achieve higher spectral efficiency (i.e. more data can be transmitted using the same bandwidth) than previously proposed modulation schemes performed by VLC transmitters based on the use of DC-DC power converters. To the author's knowledge, the ratio between the bit rate achieved and the switching frequency of the DC-DC power converter presented in this paper is the highest that can be found in literatur

Class E/F switching power amplifiers

The present invention discloses a new family of switching amplifier classes called class E/F amplifiers. These amplifiers are generally characterized by their use of the zero-voltage-switching (ZVS) phase correction technique to eliminate of the loss normally associated with the inherent capacitance of the switching device as utilized in class-E amplifiers, together with a load network for improved voltage and current wave-shaping by presenting class-F.sup.-1 impedances at selected overtones and class-E impedances at the remaining overtones. The present invention discloses a several topologies and specific circuit implementations for achieving such performance

Class D Audio Amplifier

This project consisted of the design, construction, and comparison testing of two implementations of analog pulse-width modulation Class D audio amplifiers. The main goal of the project was to maximize the efficiency of the amplifier designs while maintaining a high-power, low-noise output signal. PCB testing confirmed that the amplifiers met our goals of greater than 90% efficiency, less than 1% total harmonic distortion and greater than 50 W output power

Combined visible and near-infrared OPA for wavelength scaling experiments in strong-field physics

We report the operation of an optical parametric amplifier (OPA) capable of producing gigawatt peak-power laser pulses with tunable wavelength in either the visible or near-infrared spectrum. The OPA has two distinct operation modes (i) generation of >350 uJ, sub 100 fs pulses, tunable between 1250 - 1550 nm; (ii) generation of >190 uJ, sub 150 fs pulses tunable between 490 - 530 nm. We have recorded high-order harmonic spectra over a wide range of driving wavelengths. This flexible source of femtosecond pulses presents a useful tool for exploring the wavelength-dependence of strong-field phenomena, in both the multi-photon and tunnel ionization regimes.Comment: 14 pages, 9 figures, This paper was published in Proceedings of SPIE 10088, Nonlinear Frequency Generation and Conversion: Materials and Devices XVI, doi 10.1117/12.225077

Migration of High Precision PulSAR Analog-to-Digital Converters to Blackfin-based Platforms

This Major Qualifying Project sought to migrate Analog Devices\u27 PulSAR line of ADCs to a more modern testing and evaluation platform, the SDP. The project resulted in more extensible daughter cards, a modular driver amplifier system, an integrated power supply design, and a software package to read and analyze the ADC data. Reference schematics were also developed and tested to showcase high performance and low power with the PulSAR converters

Portable DAC and Headphone Amplifier for High Impedance Headphones

The following paper contains an in-depth report on the design process of a portable DAC and Amplifier for high impedance headphones. The project brings portability into an audiophile’s world. This portable DAC and Class D amplifier takes USB data from a phone, converts it to analog, and amplifies the signal for high impedance headphones. First, the document contains motivations for the project: such as the necessity for such equipment, and who would use this product. Next, discussions of marketing considerations and customer needs bring together specifications. After, the report examines the project plan, overall functionality blocks, and estimated costs. Finally, the last chapter discusses a full description on each part of the product

Techniques for Wideband All Digital Polar Transmission

abstract: Modern Communication systems are progressively moving towards all-digital transmitters (ADTs) due to their high efficiency and potentially large frequency range. While significant work has been done on individual blocks within the ADT, there are few to no full systems designs at this point in time. The goal of this work is to provide a set of multiple novel block architectures which will allow for greater cohesion between the various ADT blocks. Furthermore, the design of these architectures are expected to focus on the practicalities of system design, such as regulatory compliance, which here to date has largely been neglected by the academic community. Amongst these techniques are a novel upconverted phase modulation, polyphase harmonic cancellation, and process voltage and temperature (PVT) invariant Delta Sigma phase interpolation. It will be shown in this work that the implementation of the aforementioned architectures allows ADTs to be designed with state of the art size, power, and accuracy levels, all while maintaining PVT insensitivity. Due to the significant performance enhancement over previously published works, this work presents the first feasible ADT architecture suitable for widespread commercial deployment.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201