A Digitally Controlled Oscillator System for SAW-Less Transmitters in Cellular Handsets

Hung, Chih‐Ming; Staszewski, Robert Bogdan; Barton, N.; Lee, Meng-Chang; Leipold, Dirk

doi:10.1109/jssc.2006.872739

Cited by 63 publications

(33 citation statements)

References 16 publications

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“…The utilization of digital ∆Σ is not limited to digital-to-analog conversion only. It is also used in analog-to-digital conversion [35][36][37][38], in phase-locked loops [39][40][41][42][43][44][45][46][47][48][49], and as a source to generate dithering signals [50][51][52][53][54][55][56], to segment the DAC further [57,58] and in multiple-input, multiple-output transceivers [59], etc. All of the above signal processing blocks are used for narrow-, wideand ultra-wide-band applications like digital audio [60][61][62], handsets [63][64][65], biomedical [66,67], TV [68][69][70], digital radio tuners [71,72] and wireless infrastructures [73][74][75].…”

Section: Introductionmentioning

confidence: 99%

Complexity and Power Reduction in Digital Delta-Sigma Modulators

Afzal

2015

Linköping Studies in Science and Technology. Dissertations

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Papers A and C are reprinted with permission from IEEE.Cover figure is an illustration of the digital cascaded error-feedback modulator.Printed by LiU-Tryck, Linköping, Sweden 2014 To my parents and teachers AbstractA number of state-of-the-art low power consuming digital delta-sigma modulator (∆Σ) architectures for digital-to-analog converters (DAC) are presented in this thesis. In an oversampling ∆Σ DAC, the primary job of the modulator is to reduce the word length of the digital control signal to the DAC and spectrally shape the resulting quantization noise. Among the ∆Σ topologies, error-feedback modulators (EFM) are well suited for so called digital to digital modulation In order to meet the demands, various modifications to the conventional EFM architectures have been proposed. It is observed that if the internal and external digital signals of the EFM are not properly scaled then not only the design itself but also the signal processing blocks placed after it, may be over designed. In order to avoid the possible wastage of resources, a number of scaling criteria are derived. In this regard, the total number of signal levels of the EFM output is expressed in terms of the input scale, the order of modulation and the type of the loop filter.Further on, it is described that the architectural properties of a unit elementbased DAC allow us to move some of the digital processing of the EFM to the analog domain with no additional hardware cost. In order to exploit the architectural properties, digital circuitry of an arbitrary-ordered EFM is split into two parts: one producing the modulated output and another producing the filtered quantization noise. The part producing the modulated output is removed after representing the EFM output with a set of encoded signals. For both the conventional and the proposed EFM architectures, the DAC structure remains unchanged. Thus, savings are obtained since the bits to be converted are not accumulated in the digital domain but instead fed directly to the DAC.A strategy to reduce the hardware of conventional EFMs has been devised recently that uses multiple cascaded EFM units. We applied the similar approach but used several cascaded modified EFM units. The compatibility issues among the units (since the output of each proposed EFM is represented by the set of encoded signals) are resolved by a number of architectural modifications. The digital processing is distributed among each unit by splitting the primary input bus. It is shown that instead of cascading the EFM units, it is enough to cascade their loop filters only. This leads not only to area reduction but also to the reduction of power consumption and critical path.All of the designs are subjected to rigorous analysis and are described mathev vi Abstract matically. The estimates of area and power consumption are obtained after synthesizing the designs in a 65 nm standard cell library provided by the foundry. Populärvetenskaplig sammanfattning vii viiiPopulärvetenskaplig sammanfattning I denna avhandling presenteras e...

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Section: Introductionmentioning

confidence: 99%

Complexity and Power Reduction in Digital Delta-Sigma Modulators

Afzal

2015

Linköping Studies in Science and Technology. Dissertations

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“…The MIM (metal insulator metal) capacitors are widely used in RF and mixed signal IC applications for the purpose of filtering (Tamijani et al 2003), matching circuits (Ismail and Abidi 2004), and oscillators (Hung et al 2006). Their characteristics such as capacitance density and voltage linearity fully depend upon characteristics of applied dielectric materials.…”

Section: Introductionmentioning

confidence: 99%

A wireless powered fully integrated SU-8-based implantable LC transponder

et al. 2010

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In this work, we report a SU-8-based fully integrated miniaturized inductively powered LC transponder for generic implantable wireless sensor applications. It consists of a 1 mm diameter octagonal spiral inductor and a micro fabricated MIM (metal insulator metal) capacitor. Polyvinylidene Fluoride-Trifluoroethylene (PVDF-TrFE) copolymer is applied as a dielectric material for the capacitor fabrication due to its high dielectric constant. The 1 mm diameter, 154 nH spiral inductor is built on top of the capacitor. The capacitor and the inductor are in parallel connection through SU-8 via holes. SU-8 is used as a packaging material due to its biocompatibility, and also it serves as an insulator between the capacitor and the spiral inductor. The operating frequencies of the LC tanks are decided by the sizes of the capacitors (45 9 45, 55 9 55, 95 9 95 and 100 9 100 lm), and measured operating frequency range is from 385 to 485 MHz. The fabricated LC tanks are held to the power transmitting coil coaxially at distances of 2, 5, 7 and 10 mm, and rectified induced voltage at the LC tank is 8.5 V with 29 dBm input power at a 5 mm distance.

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“…The VCO needs a wide tuning range to counter the effect of fabrication uncertainties. In [2], multiple banks of varactors were implemented on chip to digitally control the capacitance value in the resonant tank through switches to cope with the variations in the temperature, process, and bias voltage.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, the performance of the RFID system is greatly degraded, including the sensitivity and the detection range. To improve the isolation between TX and RX, the conventional solution is to employ two separated antennas, but the size and cost of the reader are increased [1,2]. Another method is to apply a circulator [3].…”

Section: Introductionmentioning

confidence: 99%