71 research outputs found
High Speed and Wide Bandwidth Delta-Sigma ADCs
No full textThis thesis describes the theory, design and implementation of a high-speed, high-performance continuous-time delta-sigma (CT??) ADC for applications such as medical imaging, high-definition video processing, and wireline and wireless communications. In order to achieve a GHz clocking speed, this thesis investigates excess loop delay compensation techniques at the system level which enable the design of a wide-bandwidth (BW), high-dynamic range (DR) CT?? modulator with good power-efficiency. This thesis demonstrates that CT?? ADCs implemented in nanometer CMOS are a power efficient alternative to Nyquist-rate ADCs for wide signal bandwidths (greater than 100MHz) and high dynamic ranges (more than 12-bit). The performance of a high-speed multi-bit CT?? modulator is often limited by the dynamic errors present in the feedback DAC. The applicable correction/calibration techniques are limited due to the modulator stability requirements. We have implemented a dynamic error correction technique which not only experimentally quantifies the level of dynamic errors but also improves the dynamic performance of the modulator.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
Integrated signaling pathway and gene expression regulatory model to dissect dynamics of <em>Escherichia coli </em>challenged mammary epithelial cells
No full textCells transform external stimuli, through the activation of signaling pathways, which in turn activate gene regulatory networks, in gene expression. As more omics data are generated from experiments, eliciting the integrated relationship between the external stimuli, the signaling process in the cell and the subsequent gene expression is a major challenge in systems biology. The complex system of non-linear dynamic protein interactions in signaling pathways and gene networks regulates gene expression. The complexity and non-linear aspects have resulted in the study of the signaling pathway or the gene network regulation in isolation. However, this limits the analysis of the interaction between the two components and the identification of the source of the mechanism differentiating the gene expression profiles. Here, we present a study of a model of the combined signaling pathway and gene network to highlight the importance of integrated modeling. Based on the experimental findings we developed a compartmental model and conducted several simulation experiments. The model simulates the mRNA expression of three different cytokines (RANTES, IL8 and TNFa) regulated by the transcription factor NF?B in mammary epithelial cells challenged with E. coli. The analysis of the gene network regulation identifies a lack of robustness and therefore sensitivity for the transcription factor regulation. However, analysis of the integrated signaling and gene network regulation model reveals distinctly different underlying mechanisms in the signaling pathway responsible for the variation between the three cytokine's mRNA expression levels. Our key findings reveal the importance of integrating the signaling pathway and gene expression dynamics in modeling. Modeling infers valid research questions which need to be verified experimentally and can assist in the design of future biological experiments
Mobility-based Time References for Wireless Sensor Networks
No full textWireless Sensor Networks require small low-cost radios to enable communication among its nodes. Since those radios must be fully integrated to reduce cost and size, integration is required also for their on-board time references, which are needed to achieve synchronization with the other nodes. To deal with the lower accuracy of integrated references with respect to standard quartz-crystal references, this thesis proposes the use of a duty-cycled wake-up radio and an impulse-radio modulation scheme to relax the allowed inaccuracy up to 1%. After a review of the fully integrated references with such level of inaccuracy and a power consumption low enough to be compliant with typical Wireless-Sensor-Networks energy sources, an oscillator referenced to the electron mobility in a MOS transistor is chosen as a viable candidate. To show that such references can achieve an inaccuracy of 1%, sources of errors for such oscillators have been analyzed and minimized. Prototypes built in a 65-nm CMOS process and in a 0.16-um CMOS process demonstrate proper operation over a wide temperature range while drawing less than 50 uW from a 1.2-V supply. Furthermore, to compensate the temperature dependence of the mobility, which affects the oscillator output frequency, a temperature compensation scheme has been devised. The compensation is based on a low-power low-voltage 65-nm CMOS temperature sensor with an inaccuracy of 0.2 °C (3 sigma) over the military temperature range. Finally, it is shown that the temperature-compensated mobility-based time reference can achieve the performance required by Wireless Sensor Nodes.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Continuous-Time Sigma-Delta Modulation for IF A/D Conversion in Radio Receivers
No full textElectrical Engineering, Mathematics and Computer Scienc
De campus als living lab: Elke universiteit worstelt met het vinden van het juiste evenwicht tussen het traditionele, netwerk- en virtuele model
No full textReal Estate Managemen
Trends voor de campus van de toekomst: Van traditioneel naar netwerk en virtueel, maar ook terug
No full textReal Estate Managemen
The Story of Lego City. A study of the representation of the city in LEGO catalogues
No full textThis thesis is focused on the representation of the city in LEGO as both a spatial and social phenomemon and explores what pre-existing norms and values are at work. The city is an amalgam of buildings and people and is full of diversity and differences, while LEGO is a toy that mimics of urban life in a simplified manner. Playing with LEGO can teach the child about the city and what kind of behaviour is considered to be proper in the city. After observation of LEGO catalogues it becomes clear that the LEGO city in spatial terms focusses on progress and innovation. The affordances that LEGO offers its customers are limited, because the city is typically a Western one. Although the lack of cultural references in the minifigures may on the other hand offer children more possibilities to use their imagination
A 4 GHz Continuous-Time ΔΣ ADC With 70dB DR and -74dBFS THD in 125MHz BW
No full textA 4 GHz third-order continuous-time ΔΣ ADC is presented with a loop filter topology that absorbs the pole caused by the input capacitance of its 4-bit quantizer and also compensates for the excess delay caused by the quantizer's latency. The ADC was implemented in 45 nm-LP CMOS and achieves 70 dB DR and -74 dBFS THD in a 125 MHz BW, while dissipating 260 mW from 1.1/1.8 V supply. The ADC occupies 0.9 mm 2 including the modulator, clock circuitry and decimation filter.Accepted Author ManuscriptElectronic Instrumentatio
A High-Linearity and Low-EMI Multilevel Class-D Amplifier
No full textThis article presents a Class-D audio amplifier for automotive applications. Low electromagnetic interference (EMI) and, hence, smaller LC filter size are obtained by employing a fully differential multilevel output stage switching at 4.2 MHz. A modulation scheme with minimal switching activity at zero input reduces idle power, which is further assisted by a gate-charge reuse scheme. It also achieves high linearity due to the high loop gain realized by a third-order feedback loop with a bandwidth of 800 kHz. The prototype, fabricated in a 180-nm high-voltage BCD process, achieves a minimum THD+N of -107.8 dB/-102 dB and a peak efficiency of 91%/87% with 8- and 4-Ω loads, respectively, while drawing 7-mA quiescent current from a 14.4-V supply. The prototype meets the CISPR 25 Class 5 EMI standard with a 5.7-dB margin using an LC filter with a cutoff frequency of 580 kHz.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationElectrical Engineering, Mathematics and Computer ScienceMicroelectronic
A 28-W, -102.2-dB THD+N Class-D Amplifier Using a Hybrid ΔΣM-PWM Scheme
No full textThis article presents a 28-W class-D amplifier for automotive applications. The combination of a high switching frequency and a hybrid multibit Δ Σ M-PWM scheme results in high linearity over a wide range of output power, as well as low AM-band EMI. As a result, only a small (150-kHz cutoff frequency), and thus low-cost, LC filter is needed to meet the CISPR-25 EMI average limit (150 kHz-30 MHz) with 10-dB margin. At 28-W output power, the proposed amplifier achieves 91% efficiency while driving a 4- Ω load from a 14.4-V supply. It attains a peak THD+N of 0.00077% (-102.2 dB) for a 1-kHz input signal. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
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