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Articles 1 - 4 of 4
Full-Text Articles in VLSI and Circuits, Embedded and Hardware Systems
Indoor Positioning Using Synchronized Ultrasonic Ofdma Signals, Julian Bartolone
Indoor Positioning Using Synchronized Ultrasonic Ofdma Signals, Julian Bartolone
Master's Theses
This paper proposes a method of short-range indoor localization using differential phase measurements of synchronized two-tone ultrasonic signals in an Orthogonal Frequency Multiple Access (OFDMA) scheme. This indoor positioning system (IPS) operates at an ultrasonic frequency of approximately 40kHz and synchronizes using an infrared signal. The OFDMA scheme allows for a receiver to process the signals from multiple transmitters continuously without the signals interfering with each other. The phases of the signals are measured using Goertzel Filters, allowing for low-complexity frequency content analysis. A MATLAB simulation using the proposed localization method is performed using four transmitter nodes in the corners …
Analog Single Sideband-Pulse Width Modulation Processor For Parametric Acoustic Arrays, Vikrant A. Marathe
Analog Single Sideband-Pulse Width Modulation Processor For Parametric Acoustic Arrays, Vikrant A. Marathe
Master's Theses
Parametric acoustic arrays are ultrasonic-based loudspeakers that produce highly directive audio. The audio must first be preprocessed and modulated into an ultrasonic carrier before being emitted into the air, where it will self-demodulate in the far field. The resulting audio wave is proportional to the double time-derivative of the square of the modulation envelope. This thesis presents a fully analog processor which encodes the audio into two Pulse Width Modulated (PWM) signals in quadrature phase and sums them together to produce a Single Sideband (SSB) spectrum around the fundamental frequency of the PWM signals. The two signals are modulated between …
Design And Fabrication Techniques Of Devices For Embedded Power Active Contact Lens, Errol Heradio Leon
Design And Fabrication Techniques Of Devices For Embedded Power Active Contact Lens, Errol Heradio Leon
Master's Theses
This thesis designed and fabricated various devices that were interfaced to an IC for an active contact lens that notifies the user of an event by detection of an external wireless signal. The contact lens consisted of an embedded antenna providing communication with a 2.4GHz system, as well as inductive charging at an operating frequency of 13.56 MHz. The lens utilized a CBC005 5µAh thin film battery by Cymbet and a manufactured graphene super capacitor as a power source. The custom integrated circuit (IC) was designed using the On Semiconductor CMOS C5 0.6 µm process to manage …
Linear Power-Efficient Rf Amplifier With Partial Positive Feedback, Matthew E. King
Linear Power-Efficient Rf Amplifier With Partial Positive Feedback, Matthew E. King
Master's Theses
Over the last decade, the number of mobile wireless devices on the market has increased substantially. New “multi-carrier” modulation schemes, such as OFDM, WCDMA, and WiMAX, have been developed to accommodate the increasing number of wireless subscribers and the demand for faster data rates within the limited commercial frequency spectrum. These complex modulation schemes create signals with high peak-to-average power ratios (PAPR), exhibiting rapid changes in the signal magnitude. To accommodate these high-PAPR signals, RF power amplifiers in mobile devices must operate under backed-off gain conditions, resulting in poor power efficiency. Various efficiency-enhancement solutions have been realized for backed-off devices …