Download or read book Reducing Phase Noise and Spurious Tones in Fractional n Synthesizers written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A frequency synthesizer is a control system which employs a reference signal from a component, such as a crystal oscillator, with excellent phase and frequency stability to synthesize higher frequencies with similarly desirable characteristics. Such a control system is at the heart of many communication schemes. Due to the digital circuitry used in frequency synthesis, it is relatively straightforward to synthesize frequencies at integer multiples of the reference signal frequency. A synthesizer which achieves this is called an integer-N frequency synthesizer. The main challenge in the design of integer-N synthesizers is to reduce phase noise introduced by circuitry while achieving a needed frequency resolution. Noise can be spectrally spread by conversions in the loop which are non-linear, so the strategy to reduce noise is two-fold. Control-loop and circuit design techniques can be used to reduce device noise, but it is also important to make sure that the noise performance is not degraded by spectral spreading within the loop. This thesis addresses primarily the latter approach with the design and implementation of circuits targeting a specific conversion within the loop. Frequency resolution of a synthesizer can be improved by introducing additional circuitry and complexity. This additional complexity makes it possible to multiply the reference frequency by a fractional number and thus achieve higher frequency resolution. A control system which achieves this is called a fractional-N frequency synthesizer. The cost associated with the increased frequency resolution is a form of noise that is deterministic called spurious noise. This spurious noise can also be spread and amplified by non-linear conversions in the control loop. A quantitative understanding of the magnitude of this noise that is not readily available in the literature was developed in this research. A comparison between several implementations of integrated frequency synthesis was also carried out in this research with the intent of providing guidelines to produce a better performing synthesizer. These implementations differ in key components of the loop where linearity is of particular importance.

Download or read book CMOS Fractional N Synthesizers written by Bram De Muer and published by Springer Science & Business Media. This book was released on 2005-12-29 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: CMOS Fractional-N Synthesizers starts with a comprehensive introduction to general frequency synthesis. Different architectures and synthesizer building blocks are discussed with their relative importance on synthesizer specifications. The process of synthesizer specification derivation is illustrated with the DCS-1800 standard as a general test case. The book tackles the design of fractional-N synthesizers in CMOS on circuit level as well as system level. The circuit level focuses on high-speed prescaler design up to 12 GHz in CMOS and on fully integrated, low-phase-noise LC-VCO design. High-Q inductor integration and simulation in CMOS is elaborated and flicker noise minimization techniques are presented, ranging from bias point choice to noise filtering techniques. On a higher level, a systematic design strategy has been developed that trades off all noise contributions and fast dynamics for integrated capacitance (area). Moreover, a theoretical DeltaSigma phase noise analysis is presented, extended with a fast non-linear analysis method to accurately predict the influence of PLL non-linearities on the spectral purity of the DeltaSigma fractional-N frequency synthesizers.

Download or read book Research on Reducing Out of band Phase Noise of Fractional n Frequency Synthesizer written by 林嘉豪 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Reduction and Cancellation of Phase Noise in Digital Frequency Synthesizers and Quadrature Receivers written by Zuow-Zun Chen and published by . This book was released on 2016 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Circuit and system techniques for reducing phase noise in frequency synthesizers, and cancelling phase noise effect in quadrature receivers are presented. Phase noise performance of digital phase-locked loops (PLLs) is limited by the time resolution of time-to-digital converters (TDC). In contrast to TDCs in the past that concentrate on the arrival time difference between the divider feedback edge and the reference signal edge. Our approach extracts the timing information that is embedded in voltage domain. This approach not only achieves a higher time resolution, lower phase noise, but also consumes less power. A digital background calibration circuit is also presented to reduce the output spurious tones when the digital PLL operates under fractional-N divisions. Ring Oscillators (ROs) have the advantage of small area, wide tuning range, and multiphase output. However, their higher phase noise and higher sensitivity to supply noise may seriously deteriorate the wanted signal in wireless receivers. To circumvent this non-ideality, a low overhead phase noise cancellation technique for ring oscillator-based quadrature receivers is presented. The proposed technique operates in background and extracts ring oscillator phase noise as well as supply-induced phase noise from the digital PLL. The obtained phase noise information is then used to restore the randomly rotated baseband signal in digital domain. In recent years, the unsilenced band at 57~64 GHz frequency range has motivated the building of high-data rate radio systems targeting wireless personal area network (WPAN) applications. To address this demand, a low-noise wide-band integer-N PLL is presented which serves as the carrier generator of a 60 GHz heterogeneous transceiver. The PLL employs sub-sampling phase detection technique to achieve low-noise performance, and provides 48 GHz LO and 12 GHz IF carrier signals for the heterogeneous transceiver.

Download or read book Technique of In band Phase Noise Reduction in Fractional N Frequency Synthesizers written by 王俊彬 and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Enabling Techniques for Low Power High Performance Fractional N Frequency Synthesizers written by Ashok Swaminathan and published by . This book was released on 2006 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Delta-sigma fractional-N phase-locked loops are used to generate high quality radio-frequency signals for use in wireless applications. To reduce the phase noise inherent to these systems, a digital-to-analog converter is used to cancel the error introduced by the fractional division process, however matching between the digital-to-analog converter and the phase-locked loop circuitry place a limit on the amount of phase noise reduction that can be achieved. Furthermore, circuit non-linearity results in the appearance of spurious tones in the phase-locked loop output. This dissertation outlines a calibration technique, and a digital quantization technique that provide solutions to these two problems. The calibration technique results in improved phase noise performance by adjusting the digital-to-analog converter gain, and thus providing better matching between the phase-locked loop circuitry and digital-to-analog converter. The digital quantization technique results in no spurious tones when specified non-linearity is applied to the quantizer output sequence and error. The calibration technique was implemented in an integrated circuit, which achieves state-of-the-art performance when compared to currently published phase-locked loops and allows for all circuitry to be integrated onto a single chip. Chapter 1 presents the calibration technique, as well as a theoretical analysis of the stability. Chapter 2 presents details on the digital quantization technique, and a mathematical proof of the absence of spurious tones. In chapter 3, results from an implemented circuit are presented, which verify the behaviour of the technique presented in chapter 1.

Download or read book Spurious Tone Mitigation in Fractional N Phase Locked Loops written by Eythan Familier and published by . This book was released on 2016 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractional-N phase-locked loops (PLLs) are widely used to synthesize local oscillator signals for modulation and demodulation in communication systems. Their phase error inevitably consists of both a periodic component made up of spurious tones and a random component called phase noise. Spurious tones are particularly harmful to the performance of typical communication systems, so most communication standards stipulate stringent limits on their maximum power in relevant frequency bands. High-performance PLLs generally contain noise-shaping coarse quantizers to control their output frequency. Such quantizers are a fundamental source of spurious tones in the PLL's phase error. This is because spurious tones are inevitably induced when the quantizer's quantization noise is subjected to nonlinear distortion from analog circuit imperfections. This dissertation presents a rigorous analysis of this effect and a way to mitigate it through the use of a class of digital quantizers with first and higher-order highpass shaped quantization noise which are optimized for spurious tone and phase noise mitigation. The first chapter of this dissertation presents a mathematical analysis of spurious tone generation via nonlinear distortion of quantization noise. It proves that subjecting the quantization noise running sum of a digital quantizer to a nonlinearity of a certain order will inevitably induce spurious tones, and shows the relation between such nonlinearity order and the range of values the quantization noise running sum takes. The results are general and apply to any digital quantizer. The second chapter of this dissertation presents a class of digital quantizers with optimal immunity to nonlinearity-induced spurious tones and with first-order highpass shaped quantization noise. It presents design solutions for digital quantizers with quantization noise that can be subjected to nonlinear distortion of a given order without inducing spurious tones, and relies on the results from the first chapter to prove that the presented solutions are optimal in terms of spurious tone generation. The third chapter of this dissertation presents digital quantizers with second and third-order highpass shaped quantization noise which can be optimized for either spurious tone or phase noise mitigation. These quantizers can replace the often-used delta-sigma modulators in high-performance PLLs to either improve spurious-tone performance at the expense of slightly higher PLL phase noise or lower PLL phase noise. The fourth chapter of this dissertation present an integrated circuit PLL which implements the second and third-order digital quantizers presented in the third chapter. It demonstrates record-setting spurious tone performance due to the use of these digital quantizers and to a new linearity-enhancement PLL timing scheme.

Download or read book Minimizing Spurious Tones in Digital Delta Sigma Modulators written by Kaveh Hosseini and published by Springer Science & Business Media. This book was released on 2011-06-25 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes several Digital Delta-Sigma Modulator (DDSM) architectures, including multi stage noise shaping (MASH), error feedback modulator (EFM) and single quantizer (SQ)-DDSM modulators, with a focus on predicting and maximizing their cycle lengths. The authors aim to demystify an important aspect of these particular DDSM structures, namely the existence of spurs resulting from the inherent periodicity of DDSMs with constant inputs. Simulink and MATLAB models and code are presented in Chapters 2–5 to enable the reader to reproduce the results in this work and to explore further. These examples will also be helpful for first-time designers of DDSMs.

Download or read book Wandering Spurs in MASH Based Fractional N Frequency Synthesizers written by Dawei Mai and published by Springer Nature. This book was released on 2022-03-11 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Few people know what wandering spurs are; fewer still know how to get rid of them. This book, which is written by those who raised awareness of wandering spurs, explained how they arise, and invented ways to get rid of them, contains valuable insights, analytical techniques and examples that will enable the reader to become an expert in the area. The book is aimed at circuit design professionals who need to ensure that their designs are not compromised by wandering spurs. In addition to insights, theory, and analysis, it contains practical circuit solutions, the performance of which are characterized experimentally. This book explains—using simulation, analysis, and experimental measurements—what wandering spurs are, how they arise, how to characterize them and, most importantly, how to get rid of them. The authors present not only theoretical analysis and simulation strategies, but also provide an overview of spectral analysis techniques for studying the phenomenon and convincing experimental results from both commercially available and custom-designed monolithic synthesizers. Explains what wandering spurs are and how they differ qualitatively from the well-known fixed spurs that plague fractional-N frequency synthesizers; Provides analytical and simulation methods to study wandering spurs and original analysis of the cause of this recently reported spectral phenomenon; Presents and analyses theoretical designs based on a conventional MASH 1-1-1 to mitigate wandering spurs; Describes measured performance for the discussed designs, confirming their effectiveness in mitigating wandering spurs.

Download or read book On the Improvement of Phase Noise in Wideband Frequency Synthesizers written by Pandelani Reuben Munyai and published by . This book was released on 2017 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless communication systems are based on frequency synthesizers that generate carrier signals, which are used to transmit information. Frequency synthesizers use voltage controlled oscillators (VCO) to produce the required frequencies within a specified period of time. In the process of generating frequency, the VCO and other electronic components such as amplifiers produce some unwanted short-term frequency variations, which cause frequency instability within the frequency of interest known as phase noise (PN). PN has a negative impact on the performance of the overall wireless communication system. A literature study conducted on this research reveals that the existing PN cancellation techniques have some limitations and drawbacks that require further attention. A new PN correction technique based on the combination of least mean square (LMS) adaptive filtering and single-loop single-bit Sigma Delta (SD) modulator is proposed. The new design is also based on the Cascaded Resonator Feedback (CRFB) architecture. The noise transfer function (NTF) of the architecture was formulated in way that made it possible to stabilize the frequency fluctuations within the in-band (frequency of interest) by locating its poles and zeros within the unit circle. The new design was simulated and tested on a commercially available software tool called Agilent Advanced Design System (ADS). Simulation results show that the new technique achieves better results when compared with existing techniques as it achieves a 104 dB signal-to-noise (SNR), which is an improvement of 9 dB when compared with the existing technique accessed from the latest publications. The new design also achieves a clean signal with minimal spurious tones within the inband with a phase noise level of -141 dBc/Hz (lower phase noise level by 28 dBc/Hz) when compared with the existing techniques.

Download or read book Modelling Simulation and Architecture Modification of Delta sigma Fractional N Frequency Synthesizers written by Zhipeng Ye and published by . This book was released on 2008 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wireless communication market has been growing rapidly in recent decades. The frequency synthesizer is a key building block in wireless transceivers. It is used as a local oscillator for frequency translation and channel selection. In this thesis, we provide a brief review of PLL frequency synthesizers. A simulation environment for delta-sigma fractional-N frequency synthesizers is built using Verilog-AMS. The digital delta-sigma modulator is modeled as a finite state machine in order to evaluate how the performance of a frequency synthesizer is affected by the cyclic behavior of the DDSM. In addition, jitter and nonlinearities are considered and added to the model. The spur-minimizing effect of an odd initial condition on the first accumulator of a MASH delta-sigma modulator is demonstrated. A noise reduction technique for a fractional-N frequency synthesizer using a multiphase voltage-controlled oscillator is proposed. We have shown that both in-band and out-of-band phase noise can be reduced by 6 dB for every two-fold increase in the number of phases. The multi-phase VCO is also applied in a dual-loop frequency synthesizer. We show that this dual loop frequency synthesizer achieves a similar power spectrum but with superior frequency resolution compared to a conventional dual-loop frequency synthesizer. We have built an experimental platform based on a Xilinx Virtex-5 FPGA board and have used it to confirm the theoretical analysis and simulations. In order to reduce the hardware consumption of a digital delta-sigma modulator, and consequently the power and area consumption, we propose a reduced complexity architecture which can achieve similar spectral performance compared with a conventional DDSM but with up to 20% lower hardware consumption. We have elaborated a rigorous design methodologies based on this idea of error masking. Individual design strategies are derived for MASH DDSMs and SQ DDSMs, both with and without dither.

Download or read book Delta Sigma FDC Based Fractional N PLLs with Multi Rate Quantizing Dynamic Element Matching written by Christian Venerus and published by . This book was released on 2013 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractional-N phase-locked loop (PLL) frequency synthesizers are ubiquitous in modern communication systems, where they are used to synthesize a signal of high spectral purity from a reference signal of much lower frequency. In order to meet the requirements of wireless communication standard, strict limitation are placed on the spectral content of the synthesized signal. In recent years, PLL based on time-to-digital converters (TDC-PLLs) have been proposed that aim at moving the complexity of the design from the analog section to the digital section of the synthesizer : the advantages are a reduction in area, cost and power consumption over competing architectures based on delta-sigma modulation and charge pumps ([Delta][Sigma]-PLLs). Although TDC-PLLs with good performance have been demonstrated, TDC quantization noise has so far kept their phase noise and spurious tone performance below that of the best comparable [Delta][Sigma]-PLLs. An alternative approach is to use a delta-sigma frequency-to-digital converter ([Delta][Sigma]FDC) in place of a TDC to retain the benefits of TDC-PLLs and [Delta][Sigma]-PLLs. Chapter 1 describes a practical [Delta][Sigma] FDC based PLL in which the quantization noise is equivalent to that of a [Delta][Sigma]-PLL. It presents a linearized model of the PLL, design criteria to avoid spurious tones in the [Delta][Sigma] FDC quantization noise, and a design methodology for choosing the loop parameters in terms of standard PLL target specifications. Chapter 2 presents a multi-rate quantizing dynamic element matching (DEM) encoder for digital to analog converters (DACs) that allows a significant reduction in the encoder power consumption with respect to a conventional encoder for oversampling DEM DACs, at the expense of a minimal signal-to-noise ratio reduction. In Chapter 3, the implementation details of a [Delta][Sigma] FDC based fractional-N phase-locked loop prototype are shown. The PLL was built to showcase the capability of the architecture analyzed in Chapter 1 to comply with the most stringent wireless communication standards. The prototype extends the architecture described in Chapter 1 by including an FDC quantization noise cancelling algorithm, and an hardware efficient implementation of a multi-rate quantizing DEM encoder for digital to frequency conversion.

Download or read book Low Phase Noise High Bandwidth Frequency Synthesis Techniques written by Scott Edward Meninger and published by . This book was released on 2005 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantization noise reduction technique is proposed that allows fractional-N frequency synthesizers to achieve high closed loop bandwidth and low output phase noise simultaneously. Quantization induced phase noise is the bottleneck in state-of-the-art synthesizer design, and results in a noise-bandwidth tradeoff that typically limits closed loop synthesizer bandwidths to be

Download or read book Pll Performance Simulation and Design written by Dean Banerjee and published by Dog Ear Publishing. This book was released on 2006-08 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended for the reader who wishes to gain a solid understanding of Phase Locked Loop architectures and their applications. It provides a unique balance between both theoretical perspectives and practical design trade-offs. Engineers faced with real world design problems will find this book to be a valuable reference providing example implementations, the underlying equations that describe synthesizer behavior, and measured results that will improve confidence that the equations are a reliable predictor of system behavior. New material in the Fourth Edition includes partially integrated loop filter implementations, voltage controlled oscillators, and modulation using the PLL.

Download or read book Advances in Analog and RF IC Design for Wireless Communication Systems written by Salvatore Levantino and published by Elsevier Inc. Chapters. This book was released on 2013-05-13 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: In less than one decade after their introduction into radio-frequency applications, digital fractional-N phase-locked loops (PLLs) have become a relevant topic in microelectronic research and a practical solution for products. In addition to the well-known advantages, such as their silicon area occupation scaling as technology node and their easier portability to new nodes, digital PLLs enable easy and low-cost implementation of calibration techniques, which substantially reduce spurious tones and remove other major analog impairments. In wideband PLLs, the ultimate level of spur performance is often bounded by the time resolution and the linearity of the time-to-digital converter within the digital PLL. Methods for mitigating its nonlinearity such as those based on element randomization and large-scale dithering are discussed. The use of fractional-N dividers based on digital-to-time converters, as a means to relax the design of the time-to-digital converter, is also reviewed. This concept is extended to the limit case of a single-bit time-to-digital converter, which provides best PLL noise–power trade-off with good spur performance.

Download or read book Direct Digital Frequency Synthesizers written by Venceslav F. Kroupa and published by John Wiley & Sons. This book was released on 1998-11-18 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the advent of integrated circuits (IC), digital systems havebecome widely used in modern electronic devices, includingcommunications and measurement equipment. Direct Digital FrequencySynthesizers (DDS) are used in communications as transmitterexciters and local oscillators in receivers. The advantages aresuperior frequency stability, the same as that of the driving clockoscillator, and short switching times. The difficulties are loweroutput frequencies and rather large spurious signals. Compiled for practicing engineers who do not have theprerequisite of a specialist's knowledge in Direct DigitalFrequency Synthesizers (DDS), this collection of 40 importantreprinted papers and 9 never-before published contributionspresents a comprehensive introduction to DDS properties and a clearunderstanding of actual devices. The information in this volume canlead to easier computer simulations and improved designs. Featured topics include: * Discussion of principles and state of the art of wide-rangeDDS * Investigation of spurious signals in DDS * Combination of DDS with Phase Lock Loops (PLL) * Examination of phase and background 'noise' in DDS * Introduction to Digital to Analog Conversion (DAC) * Analysis of mathematics of quasiperiodic omission ofpulses DDFS can also serve as a textbook for students seeking essentialbackground theory.

Download or read book MicroCMOS Design written by Bang-Sup Song and published by CRC Press. This book was released on 2017-12-19 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: MicroCMOS Design covers key analog design methodologies with an emphasis on analog systems that can be integrated into systems-on-chip (SoCs). Starting at the transistor level, this book introduces basic concepts in the design of system-level complementary metal-oxide semiconductors (CMOS). It uses practical examples to illustrate circuit construction so that readers can develop an intuitive understanding rather than just assimilate the usual conventional analytical knowledge. As SoCs become increasingly complex, analog/radio frequency (RF) system designers have to master both system- and transistor-level design aspects. They must understand abstract concepts associated with large components, such as analog-to-digital converters (ADCs) and phase-locked loops (PLLs). To help readers along, this book discusses topics including: Amplifier basics & design Operational amplifier (Opamp) Data converter basics Nyquist-rate data converters Oversampling data converters High-resolution data converters PLL basics Frequency synthesis and clock recovery Focused more on design than analysis, this reference avoids lengthy equations and instead helps readers acquire a more hands-on mastery of the subject based on the application of core design concepts. Offering the needed perspective on the various design techniques for data converter and PLL design, coverage starts with abstract concepts—including discussion of bipolar junction transistors (BJTs) and MOS transistors—and builds up to an examination of the larger systems derived from microCMOS design.