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- Creators: Kitchen, Jennifer
Description
Radio frequency (RF) transceivers require a disproportionately high effort in terms of test development time, test equipment cost, and test time. The relatively high test cost stems from two contributing factors. First, RF transceivers require the measurement of a diverse set of specifications, requiring multiple test set-ups and long test times, which complicates load-board design, debug, and diagnosis. Second, high frequency operation necessitates the use of expensive equipment, resulting in higher per second test time cost compared with mixed-signal or digital circuits. Moreover, in terms of the non-recurring engineering cost, the need to measure complex specfications complicates the test development process and necessitates a long learning process for test engineers. Test time is dominated by changing and settling time for each test set-up. Thus, single set-up test solutions are desirable. Loop-back configuration where the transmitter output is connected to the receiver input are used as the desirable test set- up for RF transceivers, since it eliminates the reliance on expensive instrumentation for RF signal analysis and enables measuring multiple parameters at once. In-phase and Quadrature (IQ) imbalance, non-linearity, DC offset and IQ time skews are some of the most detrimental imperfections in transceiver performance. Measurement of these parameters in the loop-back mode is challenging due to the coupling between the receiver (RX) and transmitter (TX) parameters. Loop-back based solutions are proposed in this work to resolve this issue. A calibration algorithm for a subset of the above mentioned impairments is also presented. Error Vector Magnitude (EVM) is a system-level parameter that is specified for most advanced communication standards. EVM measurement often takes extensive test development efforts, tester resources, and long test times. EVM is analytically related to system impairments, which are typically measured in a production test i environment. Thus, EVM test can be eliminated from the test list if the relations between EVM and system impairments are derived independent of the circuit implementation and manufacturing process. In this work, the focus is on the WLAN standard, and deriving the relations between EVM and three of the most detrimental impairments for QAM/OFDM based systems (IQ imbalance, non-linearity, and noise). Having low cost test techniques for measuring the RF transceivers imperfections and being able to analytically compute EVM from the measured parameters is a complete test solution for RF transceivers. These techniques along with the proposed calibration method can be used in improving the yield by widening the pass/fail boundaries for transceivers imperfections. For all of the proposed methods, simulation and hardware measurements prove that the proposed techniques provide accurate characterization of RF transceivers.
ContributorsNassery, Afsaneh (Author) / Ozev, Sule (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Kiaei, Sayfe (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2013
Description
Synchronous buck converters have become the obvious choice of design for high efficiency voltage down-conversion applications and find wide scale usage in today's IC industry. The use of digital control in synchronous buck converters is becoming increasingly popular because of its associated advantages over traditional analog counterparts in terms of design flexibility, reduced use of off-chip components, and better programmability to enable advanced controls. They also demonstrate better immunity to noise, enhances tolerance to the process, voltage and temperature (PVT) variations, low chip area and as a result low cost. It enables processing in digital domain requiring a need of analog-digital interfacing circuit viz. Analog to Digital Converter (ADC) and Digital to Analog Converter (DAC). A Digital to Pulse Width Modulator (DPWM) acts as time domain DAC required in the control loop to modulate the ON time of the Power-MOSFETs. The accuracy and efficiency of the DPWM creates the upper limit to the steady state voltage ripple of the DC - DC converter and efficiency in low load conditions. This thesis discusses the prevalent architectures for DPWM in switched mode DC - DC converters. The design of a Hybrid DPWM is presented. The DPWM is 9-bit accurate and is targeted for a Synchronous Buck Converter with a switching frequency of 1.0 MHz. The design supports low power mode(s) for the buck converter in the Pulse Frequency Modulation (PFM) mode as well as other fail-safe features. The design implementation is digital centric making it robust across PVT variations and portable to lower technology nodes. Key target of the design is to reduce design time. The design is tested across large Process (+/- 3σ), Voltage (1.8V +/- 10%) and Temperature (-55.0 °C to 125 °C) and is in the process of tape-out.
ContributorsKumar, Amit (Author) / Bakkaloglu, Bertan (Thesis advisor) / Song, Hongjiang (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2013
Description
This thesis describes the design process used in the creation of a two stage cellular power amplifier. A background for understanding amplifier linearity, device properties, and ACLR estimation is provided. An outline of the design goals is given with a focus on linearity with high efficiency. The full design is broken into smaller elements which are discussed in detail. The main contribution of this thesis is the description of a novel interstage matching network topology for increasing efficiency. Ultimately the full amplifier design is simulated and compared to the measured results and design goals. It was concluded that the design was successful, and used in a commercially available product.
ContributorsSpivey, Erin (Author) / Aberle, James T., 1961- (Thesis advisor) / Kitchen, Jennifer (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
Doppler radar can be used to measure respiration and heart rate without contact and through obstacles. In this work, a Doppler radar architecture at 2.4 GHz and a new signal processing algorithm to estimate the respiration and heart rate are presented. The received signal is dominated by the transceiver noise, LO phase noise and clutter which reduces the signal-to-noise ratio of the desired signal. The proposed architecture and algorithm are used to mitigate these issues and obtain an accurate estimate of the heart and respiration rate. Quadrature low-IF transceiver architecture is adopted to resolve null point problem as well as avoid 1/f noise and DC offset due to mixer-LO coupling. Adaptive clutter cancellation algorithm is used to enhance receiver sensitivity coupled with a novel Pattern Search in Noise Subspace (PSNS) algorithm is used to estimate respiration and heart rate. PSNS is a modified MUSIC algorithm which uses the phase noise to enhance Doppler shift detection. A prototype system was implemented using off-the-shelf TI and RFMD transceiver and tests were conduct with eight individuals. The measured results shows accurate estimate of the cardio pulmonary signals in low-SNR conditions and have been tested up to a distance of 6 meters.
ContributorsKhunti, Hitesh Devshi (Author) / Kiaei, Sayfe (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Bliss, Daniel (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2013
Description
This thesis work mainly examined the stability and reliability issues of amorphous Indium Gallium Zinc Oxide (a-IGZO) thin film transistors under bias-illumination stress. Amorphous hydrogenated silicon has been the dominating material used in thin film transistors as a channel layer. However with the advent of modern high performance display technologies, it is required to have devices with better current carrying capability and better reproducibility. This brings the idea of new material for channel layer of these devices. Researchers have tried poly silicon materials, organic materials and amorphous mixed oxide materials as a replacement to conventional amorphous silicon layer. Due to its low price and easy manufacturing process, amorphous mixed oxide thin film transistors have become a viable option to replace the conventional ones in order to achieve high performance display circuits. But with new materials emerging, comes the challenge of reliability and stability issues associated with it. Performance measurement under bias stress and bias-illumination stress have been reported previously. This work proposes novel post processing low temperature long time annealing in optimum ambient in order to annihilate or reduce the defects and vacancies associated with amorphous material which lead to the instability or even the failure of the devices. Thin film transistors of a-IGZO has been tested for standalone illumination stress and bias-illumination stress before and after annealing. HP 4155B semiconductor parameter analyzer has been used to stress the devices and measure the output characteristics and transfer characteristics of the devices. Extra attention has been given about the effect of forming gas annealing on a-IGZO thin film. a-IGZO thin film deposited on silicon substrate has been tested for resistivity, mobility and carrier concentration before and after annealing in various ambient. Elastic Recoil Detection has been performed on the films to measure the amount of hydrogen atoms present in the film. Moreover, the circuit parameters of the thin film transistors has been extracted to verify the physical phenomenon responsible for the instability and failure of the devices. Parameters like channel resistance, carrier mobility, power factor has been extracted and variation of these parameters has been observed before and after the stress.
ContributorsRuhul Hasin, Muhammad (Author) / Alford, Terry L. (Thesis advisor) / Krause, Stephen (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2013
Description
With the advent of parallel processing, primarily the time-interleaved pipeline ADCs, high speed and high resolution ADCs became a possibility. When these speeds touch giga samples per second and resolutions go beyond 12-bits, the parallelization becomes more extensive leading to repeated presence of several identical blocks in the architecture. This thesis discusses one such block, the sub-ADC (Flash ADC), of the pipeline and sharing it with more than two of the parallel processing channels thereby reducing area and power and input load capacitance to each stage. This work presents a design of 'sub-ADC shared in a time-interleaved pipeline ADC' in the IBM 8HP process. It has been implemented with an offset-compensated, kickback-compensated, fast decision making (large input bandwidth) and low power comparator that forms the core part of the design.
ContributorsBikkina, Phaneendra Kumar (Author) / Barnaby, Hugh (Thesis advisor) / Mikkola, Esko (Committee member) / Kitchen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2013
Description
In thesis, a test time reduction (a low cost test) methodology for digitally-calibrated pipeline analog-to-digital converters (ADCs) is presented. A long calibration time is required in the final test to validate performance of these designs. To reduce total test time, optimized calibration technique and calibrated effective number of bits (ENOB) prediction from calibration coefficient will be presented. With the prediction technique, failed devices can be identified only without actual calibration. This technique reduces significant amount of time for the total test time.
ContributorsKim, Kibeom (Author) / Ozev, Sule (Thesis advisor) / Kitchen, Jennifer (Committee member) / Barnaby, Hugh (Committee member) / Arizona State University (Publisher)
Created2013
Description
E-Strings Academy (www.estringsacademy.wordpress.com) is a resource website intended for the beginning violinist, violist, cellist, and bassist. The mission of the website is to extend musical learning opportunities to students outside of the physical string classroom and to engage first-year string students in musical activities at home that supplement the instruction they receive in a school setting. The current website features five different areas for students to explore: lesson videos, tunes, listening activities, games, and resources. In each area, students have the opportunity to learn and reinforce musical concepts and skill sets that they will need in order to be successful in music, both in their first year of playing and beyond. I created E-Strings Academy with the intention that I use it with my own string students in my future teaching career. It is a flexible website that I will continue to revise, adapt, and enhance to best serve the needs of my students and enrich their musical learning outside of the classroom.
ContributorsCook, Christa Marie (Author) / Schmidt, Margaret (Thesis director) / Tobias, Evan (Committee member) / Barrett, The Honors College (Contributor) / School of Music (Contributor)
Created2015-05
Description
"French Vanilla" is a collection of written narratives drawn from lived experiences which serve as the vehicle storytelling that I use to examine larger themes related to the intersections of race and gender. Themes include: binaries, legitimacy, intersectionality, biracial identity development (border identity construction), whiteness, shame, and crisis. While the narratives are situated within theoretical discourse, the narratives present a representation of the lived experience. These pieces engage members of my family as well as a number of figures, including Rachel Dolezal, President Barack Obama, Alicia Keys, and a stranger on a tram in an airport. My relationship with these people present the grounds for an interrogation of identity. This project asks the question: How does one negotiate biracial identity with herself and others through narrative performance? It engages theories, such as critical race theory, black feminist theory, and standpoint theory, which informed my understanding of the discourse of race and contextualized my commentary on race. These theories present a framework within which to situate my understanding and analysis of race through lived experience. Narrative performance, the formal methodology for this work, provides a structure for the performance itself: the ultimate end product. Note: This work of creative scholarship is rooted in collaboration between three female artist-scholars: Carly Bates, Raji Ganesan, and Allyson Yoder. Working from a common intersectional, feminist framework, we served as artistic co-directors of each other's solo pieces and co-producers of Negotiations, in which we share these pieces in relationship to each other. Thus, Negotiations is not a showcase of three individual works, but rather a conversation among three voices. As collaborators, we have been uncompromising in the pursuit of our own unique inquiries and voices, and each of our works of creative scholarship stand alone. However, we believe that all of the parts are best understood in relationship to each other and to the whole. For this reason, we have chosen to cross-reference our thesis documents: French Vanilla: An Exploration of Biracial Identity Through Narrative Performance by Carly Bates; Deep roots, shared fruits: Emergent creative process and the ecology of solo performance through "Dress in Something Plain and Dark" by Allyson Yoder; and Bhairavi: A Performance-Investigation of Belonging and Dis-Belonging in Diaspora Communities by Raji Ganesan.
ContributorsBates, Carly Christopher (Author) / Davis, Olga Idriss (Thesis director) / de la Garza, Sarah Amira (Committee member) / Dove-Viebahn, Aviva (Committee member) / School of Music (Contributor) / Department of English (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Of Leto: a staged concert reading is a new work development created by Alexander Tom and Daniel Oberhaus focusing on collegiate collaboration, production process, and creative intuition. An original story was adapted by Daniel Oberhaus into a working libretto. Alexander Tom created a two-act musical-drama and utilized the colleges on the Arizona State University \u2014 Tempe campus: Barrett, the Honors College, W.P. Carey School of Business, the College of Liberal Arts and Sciences, and the Herberger Institute for Design and the Arts: School of Music and School of Theatre, Film and Dance. This cross-discipline staged concert reading was comprised of a libretto by Daniel Oberhaus, music, additional lyrics and orchestrations by Alexander Tom, and orchestrations by Drew Nichols. The performance included a thirteen-piece orchestra and fourteen vocalists in undergraduate and graduate programs. This paper includes research on Benjamin Britten and Myfanwy Piper's Death in Venice and Stephen Sondheim and Hugh Wheeler's Sweeney Todd, the Demon Barber of Fleet Street. Its purpose is to impart a comparative analysis on the process of collaboration in opera, musical theatre, and the newly determined "musical-drama" \u2014 the genre in which Of Leto resides. Use of historical research will expound on the evolution of musical theatre along with each team's collaborative processes in relation to the music (lyrics and melody respectively), the libretto, and the production. The research permits conclusions regarding the possible practices to utilize in creating new student works like Of Leto.
ContributorsTom, Alexander Robert (Author) / DeMars, James (Thesis director) / Swoboda, Deanna (Committee member) / Yatso, Toby (Committee member) / School of Music (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05