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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design Techniques for Timing Circuits in Wireline and Wireless Communication Systems

Huang, Deping January 2014 (has links)
Clock and data recovery (CDR) circuit and frequency synthesizer are two essential timing circuits in wireline and wireless communication systems, respectively. With multigigabits/s high speed links and emerging 4G wireless system widely used in communication backbone infrastructures and consumer electronic devices, effective design of CDR and frequency synthesizer has become more and more important. The advanced scaled-down CMOS process has the limitations of leakage current, low supply voltage and process variation which pose great challenge to the analog circuit design. To overcome these issues, a digital intensive CDR solution is needed. Besides, it is desirable for the CDR to cover a wide range of data-rate and to be reference-less for improved flexibility. As for the frequency synthesizer design, the support for multi-standard to reduce the cost and area is desirable. In this work, a digital reference-less CDR is proposed to support continuous datarate ranging from 1 Gbps to 16 Gbps. The CDR adopts an 8 GHz~16 GHz DCO to achieve low random noise performance. A reference-less digital frequency locking loop is included in the system as the acquisition assistance for the CDR loop. To address the difficulty of jitter and stability evaluations for bang-band CDR, a Simulink model is developed to find out the jitter transfer (JTRAN), jitter generation (JGEN) and jitter tolerance (JTOL) performances for the CDR. The prototype CDR is implemented in a 65 nm CMOS process. The core area is 0.68 mm². At 16 Gbps, the CDR consumes a power of 92.5 mW and is able to tolerate a sinusoidal jitter with an amplitude of 0.4 UI and a frequency of 4 MHz. The second part of this dissertation develops a frequency synthesizer for multistandard wireless receivers. The frequency synthesizer is based on an analog fractional-N PLL. Optimally-coupled quadrature voltage-controlled-oscillator (QVCO), dividers and harmonic rejection single sideband mixer (HR-SSBmixer) are combined to synthesize the desired frequency range without posing much phase noise penalty on the QVCO. The QVCO adopts a new phase-shift scheme to improve phase noise and to eliminate bimodal oscillation. Combining harmonic rejection and single sideband mixing, the HR-SSBmixer is developed to suppress spurious signals. Designed in a 0.13-μm CMOS technology, the synthesizer occupies an active area of 1.86 mm² and consumes 35.6 to 52.62 mW of power. Measurement results show that the synthesizer frequency range, the phase noise, the settling time and the spur performances meet the specifications of the wireless receivers for the above standards. For a wide range frequency synthesizer, an automatic frequency calibration circuit (AFC) is needed to select proper oscillator tuning curve before the PLL settling. An improved counter-based AFC is proposed in this dissertation that provides a more robust and faster tuning curve searching process. The proposed AFC adopts a time-to-digital converter (TDC), which is able to captures the fractional VCO cycle information within the counting window, to improve the AFC frequency detection accuracy. The TDC-based AFC is designed in a 0.13-μm CMOS technology. Simulation results show that the TDCbased AFC greatly improves the frequency detection accuracy and consequently for a given frequency detection resolution reduces the AFC calibration time.
2

Mesure de distance absolue utilisant l'interférométrie à balayage de longueur d'onde étalonnée par un peigne de fréquences / Absolute distance measurement using frequency sweeping interferometry calibrated by frequency comb

Yu, Wenhui 10 April 2019 (has links)
Dans cette thèse, nous avons mis en oeuvre un système de mesure de distance absolue (Absolute Distance Measurement, ADM) de haute précision utilisant l'interférométrie à balayage de fréquence (Frequency Sweeping Interferometry, FSI). La technique FSI exige que la plage de réglage de fréquence du laser balayé soit mesurée avec une précision élevée, ce qui est difficile en raison de l'absence d'un moyen simple de mesurer la haute fréquence d'un laser en temps réel. Dans cette thèse, un peigne de fréquence a été utilisé comme règle de fréquence lumière pour mesurer la plage de réglage de la fréquence du laser à balayage. Un peigne de fréquence formé par un laser femtoseconde est constitué de millions de lignes de peigne régulièrement espacées, ce qui permet de le considérer comme une règle de fréquence de la lumière. La calibration de fréquence a été réalisée en filtrant le signal hétérodyne entre le laser à balayage et les lignes de peigne en utilisant un filtre passe-bande étroit. Cette approche nous permet de détecter le signal d'étalonnage lorsque la fréquence du laser à balayage est proche d'une ligne en peigne. Etant donné que l’intervalle de fréquence entre les lignes de peigne peut être mesuré avec précision ou activement verrouillé en phase par rapport à un oscillateur radiofréquence (RF) stable, la plage d ’ accord du laser à balayage peut être mesurée avec une grande précision. En particulier, chacun des deux pics d’étalonnage peut être utilisé dans le calcul de la distance, ce que nous appelons des «sous-mesures» en un seul balayage. Combinée au grand nombre de lignes de peigne, la moyenne des sous-mesures améliore considérablement la précision des mesures sans balayage multiple. Dans la thèse, la condition de détection et les caractéristiques du signal hétérodyne entre le laser à balayage et la ligne de peigne sont présentées. Une conception de filtre pour filtrer le signal hétérodyne est réalisée. Un travail de modélisation concernant l'effet du bruit de phase des lasers sur la distorsion d'enveloppe du pic d'étalonnage a été présenté. Des travaux expérimentaux basés sur les concepts de mesure ont été réalisés. Il montre que l'utilisation du schéma de mesure proposé peut considérablement améliorer la précision de la mesure de distance. Dans l’une des mesures, une précision de 30 nm pour une distance d’environ 0,8 m, correspondant à une incertitude relative de 37 ppm (part-perbillion) a été obtenue. Le résultat a été obtenu sur la base d'une méthode de traitement du signal de comptage de franges. La grande précision a été obtenue grâce au grand nombre de sous-mesures et à la stabilité des lignes de peigne régulièrement espacées. Nous avons constaté que la mesure de vibration de la cible peut également être effectuée en prenant avantage des lignes de peigne denses. Une sensibilité élevée, limitée à 1,7 nm efficace en bruit, de la mesure des vibrations a été atteinte. Ce résultat nous permet de surveiller la vibration de la cible, ce qui est un problème important de la technique FSI. / In this thesis, we implemented a high-precision absolute distance measurement (ADM) system using frequency sweeping interferometry (FSI). The FSI technique requires the frequency tuning range of the swept laser to be measured with high accuracy and precision, which is challenging due to the lack of an easy way to measure the high frequency of a laser in real time. In this thesis, a frequency comb has been used as the light frequency ruler for measuring the frequency tuning range of the sweeping laser. A frequency comb formed by a femtosecond laser consists millions of evenly spaced comb lines so that can be regarded as a light frequency ruler. The frequency calibration was realized by filtering the heterodyne signal between the sweeping laser and the comb lines using a narrow bandpass filter. This approach allows us to detect the calibration signal when the frequency of the sweeping laser is in the vicinity of a comb line. As the frequency interval between the comb lines space can be precisely measured or actively phase-locked against a stable radio-frequency (RF) oscillator, the tuning range of the sweeping laser could be measured with high accuracy. Especially, each two calibration peaks can be used in the calculation of distance, which we call sub-measurements in a single sweeping. Combined with the large number of the comb lines, averaging of the sub-measurements improves greatly the measurement precision without multiple sweeping. In the thesis, the condition of detecting and the characteristics of the heterodyne signal between the sweeping laser and the comb line are presented. A filter design for filtering the heterodyne signal is performed. A modeling work concerning the effect of the phase noise of lasers on the envelope distortion of the calibration peak has been presented. Experimental works based on the measurement concepts have been carried out. It shows that using the proposed measurement scheme can greatly improve the distance measurement precision. In one of the measurements, a precision of 30 nm for a distance around 0.8 m, corresponding to 37 ppb (part-per-billion) relative uncertainty has been achieved. The result was obtained based on a fringe counting signal processing method. The high precision was obtained thanks to the large number of sub-measurements and the stability of the evenly spaced comb lines. We have found that vibration measurement of the target can be also performed taking the advantage of the dense comb lines. A high sensitivity, limited by 1.7 nm noise RMS, of vibration measurement has been achieved. This result allows us to monitor the vibration of the target, which is an important issue of FSI technique.

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