Bandpass delta-sigma modulators for radio receivers

This thesis concerns discrete-time (DT) bandpass (BP) ΔΣ modulators targeted for intermediate frequency (IF) analog-to-digital (A/D) conversion in radio receivers. The receiver architecture adopted has to be capable of operating with different radio frequencies, channel bandwidths, and modulation techniques. This is necessary in order to achieve an extensive operating area and the possibility of utilizing a local mobile phone standard or a standard suitable for a specific service. The digital IF receiver is a good choice for a multi-mode and multi-band mobile phone receiver, because the signal demodulation and channel filtering are performed in the digital domain. This increases the flexibility of the receiver and relieves the design of the baseband part, but an A/D conversion with high dynamic range and low power dissipation is required. BP ΔΣ modulators are capable of converting a high-frequency narrow band signal and are therefore suitable for signal digitization in an IF receiver. First, the theory of BP ΔΣ modulators is introduced. It has been determined that resonators are the most critical circuit blocks in the implementation of a high performance BP ΔΣ modulator. Different DT resonator topologies are studied and a double-delay (DD) resonator is found to be the best candidate for a high quality resonator. A new DD switched-capacitor (SC) resonator structure has been designed. Furthermore, two evolution versions of the designed SC resonator are presented and their nonidealities are analyzed. The three designed DD SC resonator structures are a main point of the thesis, together with the experimental results. Five different DT BP ΔΣ modulator circuit structures have been implemented and measured. All three of the designed SC resonators are used in the implemented circuits. The experimental work consists of both single-bit and multi-bit structures, as well as both single-loop and cascade architectures. The circuits have been implemented with a 0.35 μm (Bi)CMOS technology and operate with a 3.0 V supply. The measured maximum signal-to-noise-and-distortion ratios (SNDRs) are 78 dB over 270 kHz (GSM), 75 dB over 1.25 MHz (IS-95), 69 dB over 1.762 MHz (DECT), and 48 dB over 3.84 MHz (WCDMA) bandwidths using a 60 MHz IF signal.reviewe

Undersampling bandpass modulator architectures

Continuous-time delta sigma modulators -- Undersampling Delta-sigma modulators for radio receivers -- A novel continuous-time delta sigma modulator -- New delta modulator based on undersampling

Energieeffiziente HF-Front-End-Schaltungsarchitekturen am Beispiel von ZigBee-Empfängern

Der Arbeit vorangestellt ist eine Literaturübersicht über die verschiedenen Empfängerarchitekturen, aus denen die homodyne Architektur als die am besten für einen energieeffizienten Empfänger wie z.B. ZigBee geeignete ausgewählt wird. Basierend auf einer Systemsimulation werden die Kennzahlen des gesamten Empfängers festgelegt und diese umgesetzt in Spezifikationen für die einzelnen Schaltungsblöcke. Aus den festgelegten Kennzahlen wird deutlich, dass im Vergleich zu anderen drahtlosen Systemen eine geringe Anforderung an das Noise Figure und die Linearität gestellt wird, aber eine hohe Anforderung der geringe Stromverbrauch darstellt. In einer weiteren Literaturübersicht werden unterschiedlichen LNA-Architekturen miteinander verglichen und bewertet. Dabei werden nicht nur die konventionellen Architekturen Common-Source-LNA und Common-Gate-LNA (CG-LNA) betrachtet, sondern auch alternative Varianten untersucht. Aufgrund der Systemanforderungen wird der CG-LNA als der am besten geeignete ausgewählt. Basierend auf dem EKV-Modell, welches das Verhalten des MOSFETs in allen Arbeitsbereichen beschreibt, wird der CG-LNA analysiert. Dabei werden speziell, die parasitären Kapazitäten des MOSFETs und die durch Kurzkanaleffekte bedingte Zunahme des Rauschens, in Abhängigkeit vom Arbeitspunkt berücksichtigt. In dieser Arbeit konnten weiterhin neue, arbeitspunktabhängige charakteristische Performancekennzahlen (weitenbezogene Source-Transkonduktanz und totale Eingangskapazität sowie Eingangszeitkonstante) des CG-LNAs definiert werden, welche in direkter Verbindung zu der verwendeten Standard-CMOS-Technologie stehen. Mit Hilfe dieser Kenngrößen können die Technologiebedingten Grenzen für den Eingangsreflexionsfaktor und das Noise Figure bestimmt werden. Mit Hilfe einer numerischen Simulation werden die Kennzahlen des CG-LNAs ermittelt. Darauf basierend wird ein Algorithmus formuliert, mittels dessen unter Berücksichtigung der festgelegten Spezifikationen für den LNA (Noise Figure und Eingangsreflexionsfaktor) der optimale Inversionskoeffizient und die dazugehörige Weite bei minimalem Arbeitspunktstrom gefunden werden kann. Die durchgeführte Optimierung zeigt, dass der günstigste Arbeitspunkt im Bereich der moderaten Inversion liegt. Die durch die Optimierung gefundenen Designparameter werden bei der anschließenden schaltungstechnischen Realisierung verwendet und die Kennzahlen des LNAs durch eine Schaltungssimulation verifiziert. Ein weiterer Schwerpunkt dieser Arbeit liegt bei der Erweiterung des entwickelten CG-LNAs um eine variabel einstellbare Verstärkung. Dazu wird ein neues Konzept zur Verstärkungseinstellung vorgestellt und umgesetzt, welches darauf basiert den Arbeitspunktstrom abzusenken. Bei der schaltungstechnischen Umsetzung werden 16 verschiedene Verstärkungsstufen realisiert, wodurch die Verstärkung des LNAs in 1 dB Schritten reduziert werden kann (eine beliebige Stufung ist ebenfalls realisierbar). Der Arbeitspunktstrom wird dabei um fast eine Größenordnung reduziert. Durch Betrachtung des SNR-Ausgangsverhältnisses wird gezeigt, dass bei einer geringeren Verstärkungseinstellung sich keine Verschlechterung des SNR-Verhältnisses im Vergleich zur größten Verstärkungseinstellung ergibt. Der in dieser Arbeit vorgestellte optimierte CG-LNA kann zukünftig in Empfängern mit vergleichbaren Anforderungen eingesetzt werden. Die einstellbare Verstärkung mit gleichzeitig reduzierter Stromaufnahme stellt dabei eine wichtige Entwicklung dar, welche maßgeblich zur Verlängerung der Batterielebensdauer bei mobilen Geräten beiträgt

Data Acquisition Applications

Data acquisition systems have numerous applications. This book has a total of 13 chapters and is divided into three sections: Industrial applications, Medical applications and Scientific experiments. The chapters are written by experts from around the world, while the targeted audience for this book includes professionals who are designers or researchers in the field of data acquisition systems. Faculty members and graduate students could also benefit from the book

Fully-photonic digital radio over fibre for future super-broadband access network applications

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityIn this thesis a Fully-Photonic DRoF (FP-DRoF) system is proposed for deploying of future super-broadband access networks. Digital Radio over Fibre (DRoF) is more independent of the fibre network impairments and the length of fibre than the ARoF link. In order for fully optical deployment of the signal conversion techniques in the FP-DRoF architecture, two key components an Analogue-to-Digital Converter (ADC) and a Digital-to-Analogue Converter (DAC)) for data conversion are designed and their performance are investigated whereas the physical functionality is evaluated. The system simulation results of the proposed pipelined Photonic ADC (PADC) show that the PADC has 10 GHz bandwidth around 60 GHz of sampling rate. Furthermore, by changing the bandwidth of the optical bandpass filter, switching to another band of sampling frequency provides optimised performance condition of the PADC. The PADC has low changes on the Effective Number of Bit (ENOB) response versus analogue RF input from 1 GHz up to 22 GHz for 60 GHz sampling frequency. The proposed 8-Bit pipelined PADC performance in terms of ENOB is evaluated at 60 Gigasample/s which is about 4.1. Recently, different methods have been reported by researchers to implement Photonic DACs (PDACs), but their aim was to convert digital electrical signals to the corresponding analogue signal by assisting the optical techniques. In this thesis, a Binary Weighted PDAC (BW-PDAC) is proposed. In this BW-PDAC, optical digital signals are fully optically converted to an analogue signal. The spurious free dynamic range at the output of the PDAC in a back-to-back deployment of the PADC and the PDAC was 26.6 dBc. For further improvement in the system performance, a 3R (Retiming, Reshaping and Reamplifying) regeneration system is proposed in this thesis. Simulation results show that for an ultrashort RZ pulse with a 5% duty cycle at 65 Gbit/s using the proposed 3R regeneration system on a link reduces rms timing jitter by 90% while the regenerated pulse eye opening height is improved by 65%. Finally, in this thesis the proposed FP-DRoF functionality is evaluated whereas its performance is investigated through a dedicated and shared fibre links. The simulation results show (in the case of low level signal to noise ratio, in comparison with ARoF through a dedicated fibre link) that the FP-DRoF has better BER performance than the ARoF in the order of 10-20. Furthermore, in order to realize a BER about 10-25 for the ARoF, the power penalty is about 4 dBm higher than the FP-DRoF link. The simulation results demonstrate that by considering 0.2 dB/km attenuation of a standard single mode fibre, the dedicated fibre length for the FP-DRoF link can be increased to about 20 km more than the ARoF link. Moreover, for performance assessment of the proposed FP-DRoF in a shared fibre link, the BER of the FP-DRoF link is about 10-10 magnitude less than the ARoF link for -19 dBm launched power into the fibre and the power penalty of the ARoF system is 10 dBm more than the FP-DRoF link. It is significant to increase the fibre link’s length of the FP-DRoF access network using common infrastructure. In addition, the simulation results are demonstrated that the FP-DRoF with non-uniform Wavelength Division Multiplexing (WDM) is more robust against four wave mixing impairment than the conventional WDM technique with uniform wavelength allocation and has better performance in terms of BER. It is clearly verified that the lunched power penalty at CS for DRoF link with uniform WDM techniques is about 2 dB higher than non-uniform WDM technique. Furthermore, uniform WDM method requires more bandwidth than non-uniform scheme which depends on the total number of channels and channels spacing

Modern Telemetry

Telemetry is based on knowledge of various disciplines like Electronics, Measurement, Control and Communication along with their combination. This fact leads to a need of studying and understanding of these principles before the usage of Telemetry on selected problem solving. Spending time is however many times returned in form of obtained data or knowledge which telemetry system can provide. Usage of telemetry can be found in many areas from military through biomedical to real medical applications. Modern way to create a wireless sensors remotely connected to central system with artificial intelligence provide many new, sometimes unusual ways to get a knowledge about remote objects behaviour. This book is intended to present some new up to date accesses to telemetry problems solving by use of new sensors conceptions, new wireless transfer or communication techniques, data collection or processing techniques as well as several real use case scenarios describing model examples. Most of book chapters deals with many real cases of telemetry issues which can be used as a cookbooks for your own telemetry related problems