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Author: Manar Ibrahim El-Chammas
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 155
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Book Description
The increasing data rate of wireline communication systems leads to more inter-symbol interference, due to the dispersive properties of the communication channel. This requires more complex equalization blocks to meet the required bit-error rate. One solution is to use an Analog-to-Digital Converter (ADC) in the front-end, thus enabling a digitally-equalized serial link. To achieve the high-data rates of these communication systems, a time-interleaved ADC is typically used. However, this type of ADC suffers from several time-varying errors, the most prominent of which is timing skew. This thesis introduces a statistics-based background calibration algorithm that compensates for the effect of timing skew. To demonstrate the background calibration algorithm, a proof-of-concept 5 bit 12 GS/s flash ADC has been fabricated in a 65 nm CMOS process. The design of this ADC takes into consideration the tight power bounds imposed on serial links by optimizing both the time-interleaved and the sub-ADC architecture. Power consumption is further reduced by using calibration circuits to correct the offset of the flash ADC's comparators. In the measured results, the timing skew correction improves the dynamic performance of the time-interleaved ADC by 12 dB, and the proof-of-concept ADC has the lowest published power consumption for ADCs with sample rates higher than 10 GS/s.
Author: Manar Ibrahim El-Chammas
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 155
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Book Description
The increasing data rate of wireline communication systems leads to more inter-symbol interference, due to the dispersive properties of the communication channel. This requires more complex equalization blocks to meet the required bit-error rate. One solution is to use an Analog-to-Digital Converter (ADC) in the front-end, thus enabling a digitally-equalized serial link. To achieve the high-data rates of these communication systems, a time-interleaved ADC is typically used. However, this type of ADC suffers from several time-varying errors, the most prominent of which is timing skew. This thesis introduces a statistics-based background calibration algorithm that compensates for the effect of timing skew. To demonstrate the background calibration algorithm, a proof-of-concept 5 bit 12 GS/s flash ADC has been fabricated in a 65 nm CMOS process. The design of this ADC takes into consideration the tight power bounds imposed on serial links by optimizing both the time-interleaved and the sub-ADC architecture. Power consumption is further reduced by using calibration circuits to correct the offset of the flash ADC's comparators. In the measured results, the timing skew correction improves the dynamic performance of the time-interleaved ADC by 12 dB, and the proof-of-concept ADC has the lowest published power consumption for ADCs with sample rates higher than 10 GS/s.
Author: Manar El-Chammas
Publisher: Springer Science & Business Media
ISBN: 146141511X
Category : Technology & Engineering
Languages : en
Pages : 138
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Book Description
This book describes techniques for time-interleaving a number of analog-to-digital data converters to achieve demanding bandwidth requirements. Readers will benefit from the presentation of a low-power solution that can be used in actual products, while alleviating the time-varying signal artifacts that typically arise when implementing such a system architecture.
Author: Luke Wang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Christopher Kaiti Su
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This thesis describes a background-calibration technique that overcomes timing errors in time-interleaved analog-to-digital converters (ADCs) in a way that is almost independent of the user-provided ADC input signal. Additive dither is widely used to achieve signal-independent background calibration of many errors in data converters [1]. For example, this technique has been used to calibrate for gain mismatch in time-interleaved ADCs [2]. In most cases, however, binary dither has been used, and binary dither is not able to detect timing errors when the user-provided ADC input is zero or constant because timing errors do not produce amplitude errors when the ADC input is constant. This thesis presents a study of the use of a random ramp-based dither signal to calibrate for timing errors in time-interleaved ADCs. To demonstrate the dither-based timing calibration, a prototype 10-bit 500-MS/s 4-channel ADC was fabricated in 40-nm CMOS. With the proposed timing calibration, the Signal-to-Noise-and-Distortion Ratio (SNDR) is 50.1 dB with a user-provided input at 249 MHz while consuming 6.2 mW, giving a figure of merit (FoM) of 48.4 fJ/step. Disabling the ramp after the timing calibration converges improves the SNDR to 51 dB and reduces the power dissipation to 5.8 mW as well as the FoM to 39.8 fJ/step. [1] H. E. Hilton, "A 10-MHz Analog-to-Digital Converter with 110-dB Linearity," Hewlett-Packard Journal, vol. 44, No. 5, pp. 105-112, Oct. 1993. [2] D. Fu, K. C. Dyer, P. J. Hurst, and S. H. Lewis, "A Digital Background Calibration Technique for Time-Interleaved Analog-to-Digital Converters," IEEE J. of Solid-State Circuits, vol. 33, No. 12, pp.1904-1911, Dec. 1998.
Author: Arthur H.M. van Roermund
Publisher: Springer Science & Business Media
ISBN: 1461445876
Category : Technology & Engineering
Languages : en
Pages : 291
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Book Description
This book is based on the 18 presentations during the 21st workshop on Advances in Analog Circuit Design. Expert designers provide readers with information about a variety of topics at the frontier of analog circuit design, including Nyquist analog-to-digital converters, capacitive sensor interfaces, reliability, variability, and connectivity. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.
Author: Norbert Herencsar
Publisher: MDPI
ISBN: 3039210408
Category : Technology & Engineering
Languages : en
Pages : 194
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Book Description
This Special Issue contains a series of excellent research works on telecommunications and signal processing, selected from the 2018 41st International Conference on Telecommunications and Signal Processing (TSP) which was held on July 4–6, 2018, in Athens, Greece. The conference was organized in cooperation with the IEEE Region 8 (Europe, Middle East, and Africa), IEEE Greece Section, IEEE Czechoslovakia Section, and IEEE Czechoslovakia Section SP/CAS/COM Joint Chapter by seventeen universities from the Czech Republic, Hungary, Turkey, Taiwan, Japan, Slovak Republic, Spain, Bulgaria, France, Slovenia, Croatia, and Poland, for academics, researchers, and developers, and serves as a premier international forum for the annual exchange and promotion of the latest advances in telecommunication technology and signal processing. The aim of the conference is to bring together both novice and experienced scientists, developers, and specialists, to meet new colleagues, collect new ideas, and establish new cooperation between research groups from universities, research centers, and private sectors worldwide. This collection of 10 papers is highly recommended for researchers, and believed to be interesting, inspiring, and motivating for readers in their further research.
Author: Yong Ching Lim
Publisher: CRC Press
ISBN: 9814669512
Category : Computers
Languages : en
Pages : 594
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Book Description
Digital signal processing is ubiquitous. It is an essential ingredient in many of today's electronic devices, ranging from medical equipment to weapon systems. It makes the difference between dumb and intelligent systems. This book is organized into five parts: (1) Introduction, which contains an account of Prof. Constantinides' contribution to the
Author: Weitao Li
Publisher: Springer
ISBN: 3319620126
Category : Technology & Engineering
Languages : en
Pages : 181
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Book Description
This book is a step-by-step tutorial on how to design a low-power, high-resolution (not less than 12 bit), and high-speed (not less than 200 MSps) integrated CMOS analog-to-digital (AD) converter, to respond to the challenge from the rapid growth of IoT. The discussion includes design techniques on both the system level and the circuit block level. In the architecture level, the power-efficient pipelined AD converter, the hybrid AD converter and the time-interleaved AD converter are described. In the circuit block level, the reference voltage buffer, the opamp, the comparator, and the calibration are presented. Readers designing low-power and high-performance AD converters won’t want to miss this invaluable reference. Provides an in-depth introduction to the newest design techniques for the power-efficient, high-resolution (not less than 12 bit), and high-speed (not less than 200 MSps) AD converter; Presents three types of power-efficient architectures of the high-resolution and high-speed AD converter; Discusses the relevant circuit blocks (i.e., the reference voltage buffer, the opamp, and the comparator) in two aspects, relaxing the requirements and improving the performance.
Author: Anu Kalidas Muralidharan Pillai
Publisher: Linköping University Electronic Press
ISBN: 9175190621
Category : Algorithms
Languages : en
Pages : 100
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Book Description
An analog-to-digital converter (ADC) is a key component in many electronic systems. It is used to convert analog signals to the equivalent digital form. The conversion involves sampling which is the process of converting a continuous-time signal to a sequence of discrete-time samples, and quantization in which each sampled value is represented using a finite number of bits. The sampling rate and the effective resolution (number of bits) are two key ADC performance metrics. Today, ADCs form a major bottleneck in many applications like communication systems since it is difficult to simultaneously achieve high sampling rate and high resolution. Among the various ADC architectures, the time-interleaved analog-to-digital converter (TI-ADC) has emerged as a popular choice for achieving very high sampling rates and resolutions. At the principle level, by interleaving the outputs of M identical channel ADCs, a TI-ADC could achieve the same resolution as that of a channel ADC but with M times higher bandwidth. However, in practice, mismatches between the channel ADCs result in a nonuniformly sampled signal at the output of a TI-ADC which reduces the achievable resolution. Often, in TIADC implementations, digital reconstructors are used to recover the uniform-grid samples from the nonuniformly sampled signal at the output of the TI-ADC. Since such reconstructors operate at the TI-ADC output rate, reducing the number of computations required per corrected output sample helps to reduce the power consumed by the TI-ADC. Also, as the mismatch parameters change occasionally, the reconstructor should support online reconfiguration with minimal or no redesign. Further, it is advantageous to have reconstruction schemes that require fewer coefficient updates during reconfiguration. In this thesis, we focus on reducing the design and implementation complexities of nonrecursive finite-length impulse response (FIR) reconstructors. We propose efficient reconstruction schemes for three classes of nonuniformly sampled signals that can occur at the output of TI-ADCs. Firstly, we consider a class of nonuniformly sampled signals that occur as a result of static timing mismatch errors or due to channel mismatches in TI-ADCs. For this type of nonuniformly sampled signals, we propose three reconstructors which utilize a two-rate approach to derive the corresponding single-rate structure. The two-rate based reconstructors move part of the complexity to a symmetric filter and also simplifies the reconstruction problem. The complexity reduction stems from the fact that half of the impulse response coefficients of the symmetric filter are equal to zero and that, compared to the original reconstruction problem, the simplified problem requires only a simpler reconstructor. Next, we consider the class of nonuniformly sampled signals that occur when a TI-ADC is used for sub-Nyquist cyclic nonuniform sampling (CNUS) of sparse multi-band signals. Sub-Nyquist sampling utilizes the sparsities in the analog signal to sample the signal at a lower rate. However, the reduced sampling rate comes at the cost of additional digital signal processing that is needed to reconstruct the uniform-grid sequence from the sub-Nyquist sampled sequence obtained via CNUS. The existing reconstruction scheme is computationally intensive and time consuming and offsets the gains obtained from the reduced sampling rate. Also, in applications where the band locations of the sparse multi-band signal can change from time to time, the reconstructor should support online reconfigurability. Here, we propose a reconstruction scheme that reduces the computational complexity of the reconstructor and at the same time, simplifies the online reconfigurability of the reconstructor. Finally, we consider a class of nonuniformly sampled signals which occur at the output of TI-ADCs that use some of the input sampling instants for sampling a known calibration signal. The samples corresponding to the calibration signal are used for estimating the channel mismatch parameters. In such TI-ADCs, nonuniform sampling is due to the mismatches between the channel ADCs and due to the missing input samples corresponding to the sampling instants reserved for the calibration signal. We propose three reconstruction schemes for such nonuniformly sampled signals and show using design examples that, compared to a previous solution, the proposed schemes require substantially lower computational complexity.
Author: Kostas Doris
Publisher: Elsevier Inc. Chapters
ISBN: 0128064560
Category : Technology & Engineering
Languages : en
Pages : 41
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Book Description
This paper reviews recent developments of interleaved Successive Approximation Analog-to-Digital converters (SAR) in deep sub-micron CMOS technologies. The discussion covers design tradeoffs and degrees of freedom related to the impact of extensive interleaving with many SAR units on bandwidth, noise, linearity, and spurious performance. The impact of interleaving mismatches on representative broadband and multi-carrier narrowband signals is also discussed. Next, two examples are given demonstrating how interleaving with many ADCs can be transformed from a weakness to a strength. The first example concerns low spurious performance enabled by redundant SAR converters and randomization of their operation. The second example presents spectral sensing techniques.
