2,813 research outputs found

    Metodologia Per la Caratterizzazione di amplificatori a basso rumore per UMTS

    Get PDF
    In questo lavoro si presenta una metodologia di progettazione elettronica a livello di sistema, affrontando il problema della caratterizzazione dello spazio di progetto dell' amplificatore a basso rumore costituente il primo stadio di un front end a conversione diretta per UMTS realizzato in tecnologia CMOS con lunghezza di canale .18u. La metodologia รจ sviluppata al fine di valutare in modo quantititativo le specifiche ottime di sistema per il front-end stesso e si basa sul concetto di Piattaforma Analogica, che prevede la costruzione di un modello di prestazioni per il blocco analogico basato su campionamento statistico di indici di prestazioni del blocco stesso, misurati tramite simulazione di dimensionamenti dei componenti attivi e passivi soddisfacenti un set di equazioni specifico della topologia circuitale. Gli indici di prestazioni vengono successivamente ulizzati per parametrizzare modelli comportamentali utilizzati nelle fasi di ottimizzazione a livello di sistema. Modelli comportamentali atti a rappresentare i sistemi RF sono stati pertanto studiati per ottimizzare la scelta delle metriche di prestazioni. L'ottimizzazione dei set di equazioni atti a selezionare le configurazione di interesse per il campionamento ha al tempo stesso richiesto l'approfondimento dei modelli di dispositivi attivi validi in tutte le regioni di funzionamento, e lo studio dettagliato della progettazione degli amplificatori a basso rumore basati su degenerazione induttiva. Inoltre, il problema della modellizzazione a livello di sistema degli effetti della comunicazione tra LNA e Mixer รจ stato affrontato proponendo e analizzando diverse soluzioni. Il lavoro ha permesso di condurre un'ottimizzazione del front-end UMTS, giungendo a specifiche ottime a livello di sistema per l'amplificatore stesso

    Preliminary human safety assessment (PHSA) for the improvement of the behavioral aspects of safety climate in the construction industry

    Get PDF
    Occupational safety in the construction industry still represents a relevant problem at a global level. In fact, the complexity of working activities in this sector requires a comprehensive approach that goes beyond normative compliance to guarantee safer working conditions. In particular, empirical research on the factors influencing the unsafe behavior of workers needs to be augmented. Thus, the relationship between human factors and safety management issues following a bottom-up approach was investigated. In particular, an easy-to-use procedure that can be used to better address workers' safety needs augmenting the company's safety climate and supporting safety management issues was developed. Such an approach, based on the assessment of human reliability factors, was verified in a real case study concerning the users of concrete mixer trucks. The results showed that the majority of human failures were action and retrieval errors, underlining the importance of theoretical and practical training programs as a means to improve safety behavior. In such a context, information and communication activities also resulted beneficially to augment the company's safety climate. The proposed approach, despite its qualitative nature, allows a clearer understanding of workers' perceptions of hazards and their risk-taking behavior, providing practical cues to monitor and improve the behavioral aspects of safety climate. Hence, these first results can contribute to augmenting safety knowledge in the construction industry, providing a basis for further investigations on the causalities related to human performances, which are considered a key element in the prevention of accidents

    5G NR-๋ฐด๋“œ ๋ฌด์„  ์ฃผํŒŒ์ˆ˜ ์†ก์ˆ˜์‹ ๊ธฐ์˜ ๊ฒ€์ฆ์„ ์œ„ํ•œ ๋ชจ๋ธ๋ง ๋ฐฉ๋ฒ•

    Get PDF
    ํ•™์œ„๋…ผ๋ฌธ(์„์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ๊ณต๊ณผ๋Œ€ํ•™ ์ „๊ธฐยท์ •๋ณด๊ณตํ•™๋ถ€, 2021.8. ๊น€์žฌํ•˜.๋„๋ž˜ํ•œ ์ดˆ์—ฐ๊ฒฐ์‹œ๋Œ€์—์„œ๋Š” ์Šค๋งˆํŠธํฐ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๋‹ค์–‘ํ•œ ์‚ฌ๋ฌผ ์ธํ„ฐ๋„ท ๋””๋ฐ”์ด์Šค๋“ค์ด 5์„ธ๋Œ€ ์ด๋™ํ†ต์‹  ์‹œ์Šคํ…œ์„ ํ™œ์šฉํ•˜๋ฉด์„œ, ๋Š˜์–ด๋‚œ ๋ฐ์ดํ„ฐ๋Ÿ‰๊ณผ ํŠธ๋ž˜ํ”ฝ์„ ๊ฐ๋‹นํ•˜๊ธฐ ์œ„ํ•ด ๋ฐ€๋ฆฌ๋ฏธํ„ฐํŒŒ ๋Œ€์—ญ์˜ ์‚ฌ์šฉ์ด ํ•„์ˆ˜์ ์ผ ๊ฒƒ์ด๋‹ค. ์‹œ์Šคํ…œ์ด ๋ณด๋‹ค ๋Œ€์šฉ๋Ÿ‰ํ™” ๊ทธ๋ฆฌ๊ณ  ๊ด‘๋Œ€์—ญํ™” ๋จ์— ๋”ฐ๋ผ, ํ†ต์‹  ๊ทœ์•ฝ์„ ๋งŒ์กฑ์‹œํ‚ค๊ธฐ ์œ„ํ•ด, ์ ์ฐจ ๊ฑฐ๋Œ€ํ•œ ๋””์ง€ํ„ธ ์บ˜๋ฆฌ๋ธŒ๋ ˆ์ด์…˜ ๋ฐ ์‹ ํ˜ธ์ฒ˜๋ฆฌ ๋กœ์ง์ด, ๋ฌด์„  ํ†ต์‹  ์ „๋‹จ๋ถ€ ์นฉ์— ํ•จ๊ป˜ ์ง‘์ ๋˜๊ณ  ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ๋ฉ€ํ‹ฐ-๋„๋ฉ”์ธ์˜ ์‹ ํ˜ธ(์•„๋‚ ๋กœ๊ทธ/๋””์ง€ํ„ธ/๋ฌด์„ ํ†ต์‹  ์‹ ํ˜ธ)๊ฐ€ ๋ณต์žกํ•˜๊ฒŒ ํ˜ผ์„ฑ๋œ ๋ฌด์„ ํ†ต์‹  ์ง‘์ ํšŒ๋กœ ์นฉ์„, ์งง์€ ๊ฐœ๋ฐœ ๊ธฐ๊ฐ„ ๋™์•ˆ ์ถฉ๋ถ„ํžˆ ๊ฒ€์ฆํ•˜๊ธฐ์—” ์–ด๋ ค์›€์ด ๋”ฐ๋ฅธ๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ํ˜ผ์„ฑ ์‹ ํ˜ธ ์‹œ์Šคํ…œ์„ ๊ฒ€์ฆํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š”, ํ•˜์œ„ ์‹œ์Šคํ…œ์„ ๋ชจ๋‘ ํฌํ•จํ•ด์„œ ์‹œ๊ฐ„ ๋„๋ฉ”์ธ์˜ ์‹œ๋ฎฌ๋ ˆ์ด์…˜์„ ์ˆ˜ํ–‰ํ•ด์•ผ ํ•˜๋Š”๋ฐ, ์ด๋ฅผ ์œ„ํ•œ ์ŠคํŒŒ์ด์Šค์™€ ์ŠคํŒŒ์ด์Šค-ํ•˜๋“œ์›จ์–ด ๊ธฐ์ˆ  ์–ธ์–ด์˜ co-์‹œ๋ฎฌ๋ ˆ์ด์…˜์€ ์ง€๋‚˜์น˜๊ฒŒ ๋Š๋ฆฌ๋‹ค๋Š” ํ•œ๊ณ„๊ฐ€ ์žˆ๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. ๋”ฐ๋ผ์„œ, ๋ฉ€ํ‹ฐ-๋„๋ฉ”์ธ์˜ ์‹ ํ˜ธ๋ฅผ ๋น ๋ฅด๊ณ  ์ •ํ™•ํ•˜๊ฒŒ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฐ€๋Šฅํ•˜๊ฒŒ ํ•˜๋Š” ๋ชจ๋ธ๋ง ๋ฐฉ๋ฒ•๊ณผ, ๋‹ค์–‘ํ•œ ์‹œ๋‚˜๋ฆฌ์˜ค์˜ ๊ฒ€์ฆ ์™„์„ฑ๋„๋ฅผ ํ–ฅ์ƒ์‹œ์ผœ์ค„ ์žˆ๋Š” ๊ฒ€์ฆ ๊ธฐ์ˆ ์ด ๋ชจ๋‘ ์š”๊ตฌ๋œ๋‹ค. ํ˜ผ์„ฑ ์‹œ์Šคํ…œ์„ ๊ฒ€์ฆํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š”, ์•„๋‚ ๋กœ๊ทธ์™€ ๋ฌด์„  ํ†ต์‹  ๋ธ”๋ก๋“ค์„ ์‹œ์Šคํ…œ ๋ฒ ๋ฆด๋กœ๊ทธ ์ƒ์—์„œ ๊ตฌํ˜„๋œ ํ•จ์ˆ˜์  ๋ชจ๋ธ๋กœ ๋Œ€์ฒดํ•˜๊ณ , ๋””์ง€ํ„ธ ๋ธ”๋ก๋“ค๊ณผ ํ•จ๊ป˜ ํ•˜๋‚˜์˜ ๋””์ง€ํ„ธ ํ”Œ๋žซํผ์—์„œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ํ•˜๋Š” ๊ฒƒ์ด ํšจ๊ณผ์ ์ด๋‹ค. ์‹ค์ œ ์„ค๊ณ„ํ•  ๋•Œ, ๋ฌธ์ œ๊ฐ€ ๋˜๋Š” ๋Œ€๋ถ€๋ถ„์˜ ์—๋Ÿฌ๋“ค์€, ์—ฐ๊ฒฐ ์˜ค๋ฅ˜, ๋ถ€ํ˜ธ ์˜ค๋ฅ˜, ์‹ ํ˜ธ ์ˆœ์„œ ์˜ค๋ฅ˜, ํ˜น์€ ์ž˜๋ชป๋œ ํŒŒ์›Œ ๋„๋ฉ”์ธ๊ณผ์˜ ์—ฐ๊ฒฐ๊ณผ ๊ฐ™์ด ์‚ฌ์†Œํ•œ ์˜ค๋ฅ˜๋“ค์ด๋‹ค. ์ด๋Ÿฌํ•œ ์˜ค๋ฅ˜๋ฅผ ์ฐพ๊ธฐ ์œ„ํ•ด, ์˜ค๋ž˜ ๊ฑธ๋ฆฌ๋Š” ํŠธ๋žœ์ง€์Šคํ„ฐ-๋ ˆ๋ฒจ์˜ ์‹œ๋ฎฌ๋ ˆ์ด์…˜์„ ์ˆ˜ํ–‰ํ•˜๊ธฐ๋ณด๋‹ค๋Š”, ์•„๋‚ ๋กœ๊ทธ ์ŠคํŒŒ์ด์Šค ๋ชจ๋ธ๋“ค์„ ์‹œ์Šคํ…œ ๋ฒ ๋ฆด๋กœ๊ทธ ๋ชจ๋ธ๋“ค๋กœ ๋Œ€์ฒดํ•˜๊ณ , ๋ณด๋‹ค ๋‹ค์–‘ํ•œ ์‹œ๋‚˜๋ฆฌ์˜ค๋ฅผ ๋น ๋ฅด๊ฒŒ ๊ฒ€์ฆํ•˜๋Š” ๋ฐฉ๋ฒ•์ด ๊ฒ€์ฆ ์™„์„ฑ๋„๋ฅผ ํ–ฅ์ƒ์‹œํ‚ค๋Š”๋ฐ ์ ํ•ฉํ•˜๋‹ค. ๊ทธ๋Ÿผ์—๋„, ์ง€๋‚˜์น˜๊ฒŒ ๋‹จ์ˆœํ•œ ์„ ํ˜• ๋ชจ๋ธ์ด๋‚˜, ์ค‘์š”ํ•œ ํšŒ๋กœ ํŠน์„ฑ์ด ๋น ์ง„ ๋ชจ๋ธ๋กœ๋Š” ์›ํ•˜๋Š” ์ˆ˜์ค€์˜ ๊ฒ€์ฆ์ด ๋ถˆ๊ฐ€๋Šฅํ•  ์ˆ˜ ์žˆ๋‹ค. ์˜ˆ๋ฅผ ๋“ค์–ด, ์ง์ ‘ ๋ณ€์กฐ ๊ตฌ์กฐ์˜ ๋ฌด์„ ํ†ต์‹  ์†ก์ˆ˜์‹ ๊ธฐ์—์„œ ๋ฐœ์ƒํ•˜๋Š” ๋น„์ด์ƒ ํšจ๊ณผ, ์ €์ „๋ ฅ ๋™์ž‘์„ ํ•˜๋ฉด์„œ ๋ฐœ์ƒํ•˜๋Š” ๋น„์„ ํ˜• ํšจ๊ณผ, ๊ทธ๋ฆฌ๊ณ  ํ”ํžˆ ๋ฉ”๋ชจ๋ฆฌ ํšจ๊ณผ๋Š” ๋ชจ๋ธ์— ํšจ๊ณผ๋ฅผ ์ถฉ๋ถ„ํžˆ ๋ฐ˜์˜ํ•ด ์ฃผ์–ด์•ผ๋งŒ, ์ฃผํŒŒ์ˆ˜ ๋„๋ฉ”์ธ์—์„œ์˜ ๊ฒ€์ฆ, ์„ฑ๋Šฅ ์˜ˆ์ธก ๋“ฑ์˜ ๊ฒ€์ฆ์„ ์˜๋ฏธ ์žˆ๊ฒŒ ์ˆ˜ํ–‰ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ฌธ์ œ๋Š” ๋น„์„ ํ˜• ์‹œ์Šคํ…œ์€ ํ›จ์”ฌ ๋ณต์žกํ•œ ์‹์œผ๋กœ ํ‘œํ˜„๋˜๋ฉฐ, ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ์‹œ ์—ฐ์‚ฐ๋Ÿ‰๋„ ํฌ๊ฒŒ ๋Š˜์–ด๋‚˜๊ธฐ ๋•Œ๋ฌธ์—, ๋น„์„ ํ˜• ๋ชจ๋ธ์„ ๋งŒ๋“ค๊ณ  ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ํ•˜๊ธฐ๊ฐ€ ์‰ฝ์ง€ ์•Š๋‹ค๋Š” ๊ฒƒ์ด๋‹ค. ๋”ฐ๋ผ์„œ ๋ชจ๋ธ์ด ๋น„์ด์ƒ์„ฑ๋“ค์„ ์ถฉ๋ถ„ํžˆ ๋ฐ˜์˜ํ•˜๋ฉด์„œ๋„ ํšจ๊ณผ์ ์ธ ๊ฒ€์ฆ์„ ๊ฐ€๋Šฅํ•˜๊ฒŒ ํ•˜๋Š” ๋ชจ๋ธ๋ง/์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๋ฐฉ๋ฒ• ์—ญ์‹œ ์š”๊ตฌ๋œ๋‹ค. ๋ณธ ํ•™์œ„ ๋…ผ๋ฌธ์—์„œ๋Š”, ๋ฌด์„ ํ†ต์‹  ์†ก์ˆ˜์‹ ๊ธฐ ์ง‘์ ํšŒ๋กœ ์ „์ฒด์˜ ๋ชจ์‚ฌ ๋ชจ๋ธ์„ ์ œ์•ˆํ•œ๋‹ค. ๋ชจ๋ธ์€ ๋ˆ„์„ค ์‹ ํ˜ธ์™€ ์‹ ํ˜ธ ๊ฐ„ ๋ถˆ์ผ์น˜์— ์˜ํ•œ ๋น„-์ด์ƒ์ ์ธ ํšจ๊ณผ๋ฅผ ์—‘์Šค๋ชจ๋ธ์˜ ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ํ™œ์šฉํ•ด ๋ฐ˜์˜ํ•˜์˜€๊ณ , ๋น„์„ ํ˜•์„ฑ๊ณผ ๋ฉ”๋ชจ๋ฆฌ ํšจ๊ณผ๋ฅผ ๋ณผํ…Œ๋ผ-์„ญ๋™๋ฒ•์„ ํ™œ์šฉํ•ด ๋ฐ˜์˜ํ•˜์˜€๋‹ค. ์ œ์•ˆํ•˜๋Š” ๋ชจ๋ธ์€ ๋‹ค์–‘ํ•œ ์ฃผํŒŒ์ˆ˜ ๋Œ€์—ญ๊ณผ ๋™์ž‘ ๋ชจ๋“œ๋ฅผ ๊ฒ€์ฆํ•˜๋Š”๋ฐ, ๊ธฐ์กด ๋“ฑ๊ฐ€ ๋ฒ ์ด์Šค๋ฐด๋“œ ๋ชจ๋ธ๋ณด๋‹ค 30~1800๋ฐฐ ๋น ๋ฅด๊ฒŒ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ํ•  ์ˆ˜ ์žˆ์—ˆ๊ณ , ๋น„์ด์ƒ ํšจ๊ณผ์— ๋Œ€ํ•ด, ํ†ต์‹  ์„ฑ๋Šฅ๋“ค(์‹ฌ๋ณผ์˜ ์˜ค๋ฅ˜ ๋ฒกํ„ฐ์˜ ํฌ๊ธฐ, ์ธ์ ‘ ์ฑ„๋„์˜ ํŒŒ์›Œ ๊ทธ๋ฆฌ๊ณ  ๋น„ํŠธ ์—๋Ÿฌ)์„ ํ‰๊ฐ€ ๊ฐ€๋Šฅํ–ˆ๋‹ค. ๋‚˜์•„๊ฐ€, ์•„๋‚ ๋กœ๊ทธ ๊ฒ€์‚ฌ๊ธฐ๋ฅผ ํ™œ์šฉํ•œ ๊ธฐ๋Šฅ ๊ฒ€์ฆ๋ฒ•๊ณผ ๋ชจ๋ธ ํŒŒ๋ผ๋ฏธํ„ฐ ์ปค๋ฒ„๋ฆฌ์ง€ ๋ถ„์„๋ฒ•์„ ์ ์šฉํ•˜์—ฌ, ์‹œ์Šคํ…œ-๋ ˆ๋ฒจ ๊ฒ€์ฆ์˜ ์™„์„ฑ๋„๋ฅผ ํ–ฅ์ƒ์‹œ์ผฐ๋‹ค. ๋ฌด์„ ํ†ต์‹  ์ง‘์ ํšŒ๋กœ ๋ชจ๋ธ์— ๋‹ค์–‘ํ•œ ๋””์ž์ธ/ํŒŒ๋ผ๋ฏธํ„ฐ ์˜ค๋ฅ˜๋ฅผ ์ฃผ์ž…ํ•˜๊ณ , ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๋™์•ˆ ๊ฒ€์‚ฌ๊ธฐ๊ฐ€ ์ฐพ์€ ์—๋Ÿฌ์˜ ๊ฐœ์ˆ˜์™€ ์ปค๋ฒ„๋ฆฌ์ง€ ๊ฒฐ๊ณผ๋ฅผ ์‹คํ—˜์ ์œผ๋กœ ๋ณด์˜€๋‹ค.In mobile RF transceiver systems, the large number of digital circuits employed to compensate or calibrate the non-idealities of the RF circuits call for models that can work within the digital verification platform, such as SystemVerilog. While baseband-equivalent real-number models (RNMs) are the current state-of-the-art for modeling RF transceivers in SystemVerilog, their simulation speeds and accuracy are not adequate predicting performance degradation. Since, its signals can only model the frequency components near the carrier frequency but not the DC offsets or high-order harmonic effects arising due to nonlinearities. Therefore, the growing impacts of nonlinearities call for nonlinear modeling of their key components to predict the overall system's performance. This dissertation presents the models for a multi-standard, direct-conversion RF transceiver for evaluating its system-level performance and verifying its digital controllers. Also, this work demonstrates the Volterra series model for the nonlinear analysis of a low-noise amplifier circuit in SystemVerilog, leveraging the functional expression and event-driven simulation capability of XMODEL. The simulation results indicate that the presented models, including the digital configuration/calibration logic for the 5G sub-6GHz-band and mmWave-band transceiver, can deliver 30โ€“1800ร— higher speeds than the baseband-equivalent RNMs while estimating the quadrature amplitude modulation signal constellation and error vector magnitude in the presence of non-idealities such as nonlinearities, DC offsets, and I/Q imbalances. In addition, it implements functionality checkers and parameter coverage analysis to advance the completeness of system-level verification of the RF transceivers model.Chapter 1. Introduction 1 1.1 Design and Verification Flow . 1.2 5G NR Band RF Transceiver IC . 1.3 Baseband-Equivalent and Passband Modeling . 1.4 Thesis Organization . Chapter 2. Modeling and Simulation of RF Transceiver 11 2.1 Direct Conversion RF Transceiver . 2.2 Proposed Transceiver Models . 2.3 System and Simulation Performance . Chapter 3. Nonlinear RF System Modeling 28 3.1 Volterra / Perturbation Method . 3.2 Low Noise Amplifier Example . 3.3 Nonlinearity Analysis . Chapter 4. Coverage Analysis and Functional Verification 42 4.1 Model Parameter Coverage Analysis . 4.2 Self-Checking Testbench . Chapter 5. Conclusion 54 Appendix 55 A.1 Trigonometric Equation for Non-Ideal Effects . A.2 RNM Baseband Equivalent Modeling . A.3 Parameter Coverage Analysis . A.4 List of Models . Bibliography 63 Abstract in Korean 66์„

    Constraint-driven RF test stimulus generation and built-in test

    Get PDF
    With the explosive growth in wireless applications, the last decade witnessed an ever-increasing test challenge for radio frequency (RF) circuits. While the design community has pushed the envelope far into the future, by expanding CMOS process to be used with high-frequency wireless devices, test methodology has not advanced at the same pace. Consequently, testing such devices has become a major bottleneck in high-volume production, further driven by the growing need for tighter quality control. RF devices undergo testing during the prototype phase and during high-volume manufacturing (HVM). The benchtop test equipment used throughout prototyping is very precise yet specialized for a subset of functionalities. HVM calls for a different kind of test paradigm that emphasizes throughput and sufficiency, during which the projected performance parameters are measured one by one for each device by automated test equipment (ATE) and compared against defined limits called specifications. The set of tests required for each product differs greatly in terms of the equipment required and the time taken to test individual devices. Together with signal integrity, precision, and repeatability concerns, the initial cost of RF ATE is prohibitively high. As more functionality and protocols are integrated into a single RF device, the required number of specifications to be tested also increases, adding to the overall cost of testing, both in terms of the initial and recurring operating costs. In addition to the cost problem, RF testing proposes another challenge when these components are integrated into package-level system solutions. In systems-on-packages (SOP), the test problems resulting from signal integrity, input/output bandwidth (IO), and limited controllability and observability have initiated a paradigm shift in high-speed analog testing, favoring alternative approaches such as built-in tests (BIT) where the test functionality is brought into the package. This scheme can make use of a low-cost external tester connected through a low-bandwidth link in order to perform demanding response evaluations, as well as make use of the analog-to-digital converters and the digital signal processors available in the package to facilitate testing. Although research on analog built-in test has demonstrated hardware solutions for single specifications, the paradigm shift calls for a rather general approach in which a single methodology can be applied across different devices, and multiple specifications can be verified through a single test hardware unit, minimizing the area overhead. Specification-based alternate test methodology provides a suitable and flexible platform for handling the challenges addressed above. In this thesis, a framework that integrates ATE and system constraints into test stimulus generation and test response extraction is presented for the efficient production testing of high-performance RF devices using specification-based alternate tests. The main components of the presented framework are as follows: Constraint-driven RF alternate test stimulus generation: An automated test stimulus generation algorithm for RF devices that are evaluated by a specification-based alternate test solution is developed. The high-level models of the test signal path define constraints in the search space of the optimized test stimulus. These models are generated in enough detail such that they inherently define limitations of the low-cost ATE and the I/O restrictions of the device under test (DUT), yet they are simple enough that the non-linear optimization problem can be solved empirically in a reasonable amount of time. Feature extractors for BIT: A methodology for the built-in testing of RF devices integrated into SOPs is developed using additional hardware components. These hardware components correlate the high-bandwidth test response to low bandwidth signatures while extracting the test-critical features of the DUT. Supervised learning is used to map these extracted features, which otherwise are too complicated to decipher by plain mathematical analysis, into the specifications under test. Defect-based alternate testing of RF circuits: A methodology for the efficient testing of RF devices with low-cost defect-based alternate tests is developed. The signature of the DUT is probabilistically compared with a class of defect-free device signatures to explore possible corners under acceptable levels of process parameter variations. Such a defect filter applies discrimination rules generated by a supervised classifier and eliminates the need for a library of possible catastrophic defects.Ph.D.Committee Chair: Chatterjee, Abhijit; Committee Member: Durgin, Greg; Committee Member: Keezer, David; Committee Member: Milor, Linda; Committee Member: Sitaraman, Sures

    Compact Digital Predistortion for Multi-band and Wide-band RF Transmitters

    Get PDF
    This thesis is focusing on developing a compact digital predistortion (DPD) system which costs less DPD added power consumptions. It explores a new theory and techniques to relieve the requirement of the number of training samples and the sampling-rate of feedback ADCs in DPD systems. A new theory about the information carried by training samples is introduced. It connects the generalized error of the DPD estimation algorithm with the statistical properties of modulated signals. Secondly, based on the proposed theory, this work introduces a compressed sample selection method to reduce the number of training samples by only selecting the minimal samples which satisfy the foreknown probability information. The number of training samples and complex multiplication operations required for coefficients estimation can be reduced by more than ten times without additional calculation resource. Thirdly, based on the proposed theory, this thesis proves that theoretically a DPD system using memory polynomial based behavioural modes and least-square (LS) based algorithms can be performed with any sampling-rate of feedback samples. The principle, implementation and practical concerns of the undersampling DPD which uses lower sampling-rate ADC are then introduced. Finally, the observation bandwidth of DPD systems can be extended by the proposed multi-rate track-and-hold circuits with the associated algorithm. By addressing several parameters of ADC and corresponding DPD algorithm, multi-GHz observation bandwidth using only a 61.44MHz ADC is achieved, and demonstrated the satisfactory linearization performance of multi-band and continued wideband RF transmitter applications via extensive experimental tests

    Multi-band OFDM UWB receiver with narrowband interference suppression

    Get PDF
    A multi band orthogonal frequency division multiplexing (MB-OFDM) compatible ultra wideband (UWB) receiver with narrowband interference (NBI) suppression capability is presented. The average transmit power of UWB system is limited to -41.3 dBm/MHz in order to not interfere existing narrowband systems. Moreover, it must operate even in the presence of unintentional radiation of FCC Class-B compatible devices. If this unintentional radiation resides in the UWB band, it can jam the communication. Since removing the interference in digital domain requires higher dynamic range of analog front-end than removing it in analog domain, a programmable analog notch filter is used to relax the receiver requirements in the presence of NBI. The baseband filter is placed before the variable gain amplifier (VGA) in order to reduce the signal swing at the VGA input. The frequency hopping period of MB-OFDM puts a lower limit on the settling time of the filter, which is inverse proportional to notch bandwidth. However, notch bandwidth should be low enough not to attenuate the adjacent OFDM tones. Since these requirements are contradictory, optimization is needed to maximize overall performance. Two different NBI suppression schemes are tested. In the first scheme, the notch filter is operating for all sub-bands. In the second scheme, the notch filter is turned on during the sub-band affected by NBI. Simulation results indicate that the UWB system with the first and the second suppression schemes can handle up to 6 dB and 14 dB more NBI power, respectively. The results of this work are not limited to MB-OFDM UWB system, and can be applied to other frequency hopping systems

    Characterization and Design of Analog Integrated Circuits Exploiting Analog Platforms

    Get PDF
    Universal Mobile Telecommunication System (UMTS) front end design is challenging because of the need to optimize power while satisfying a very high dynamic range requirement. At the same time, designing analog circuits for automotive applications is very difficult because of the wide temperature range (from -40 to 125 degrees at least) they must tolerate. Dealing with this design problems at the transistor level does not allow to explore efficiently the design space, while using behavioral models does not allow to take into consideration important second-order effects. We present an extension of the platform-based design methodology originally developed for digital systems to the analog domain to conjugate the need of higher levels of abstraction to deal with complexity as well as the one of capturing enough of the actual circuit-level characteristics to deal with second order effects. This methodology is based on the concept of Analog Platform and is very useful both to characterize an analog circuit and to perform a system level optimization. We show how this methodology applied to the UMTS front-end design yields power savings as large as 47% versus an original hand optimized design. Besides, we give details on how to design an RC oscillator for automotive applications and to get its main performances at the aim of characterizing it

    Simply tell me how -- On Trustworthiness and Technology Acceptance of Attribute-Based Credentials

    Full text link
    Attribute-based Credential Systems (ACS) have been long proposed as privacy-preserving means of attribute-based authentication, yet neither been considered particularly usable nor found wide-spread adoption, to date. To establish what variables drive the adoption of \ACS as a usable security and privacy technology, we investigated how intrinsic and presentation properties impact their perceived trustworthiness and behavioral intent to adopt them. We conducted two confirmatory, fractional-factorial, between-subject, random-controlled trials with a total UK-representative sample of N=812N = 812 participants. Each participant inspected one of 24 variants of Anonymous Credential System Web site, which encoded a combination of three intrinsic factors (\textsf{provider}, \textsf{usage}, \textsf{benefits}) and three presentation factors (\textsf{simplicity}, presence of \textsf{people}, level of available \textsf{support}). Participants stated their privacy and faith-in-technology subjective norms before the trial. After having completed the Web site inspection, they reported on the perceived trustworthiness, the technology adoption readiness, and their behavioral intention to follow through. We established a robust covariance-based structural equation model of the perceived trustworthiness and technology acceptance, showing that communicating facilitating conditions as well as demonstrating results drive the overall acceptance and behavioral intent. Of the manipulated causal variables, communicating with simplicity and on the everyday usage had the greatest and most consistently positive impact on the overall technology acceptance. After earlier correlational empirical research on ACS technology acceptance, ours is the first research showing cause-effect relations in a structural latent factor model with substantial sample size.Comment: 15 pages. Work funded by the ERC Starting Grant CASCAde (GA no 716980
    • โ€ฆ
    corecore