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A low-power high linearity CMOS G(m)-C channel select filter for WLAN/WiMAX receivers in 90-nm CMOS technology is presented. To reduce power consumption a biquad cell with simple architecture is used. A simple but efficient technique is also proposed to improve the linearity of the filter without increasing its power consumption. Coarse and fine tuning techniques are used to tune the cutoff freque
From the network layer perspective, the problem of burst losses is one of the most challenging problems which restrain the development of optical burst switching (OBS) networks. Indeed, OBS is a buffer-less technology and the consequent lack of guarantees for data delivery may affect significantly the quality of service (QoS) perceived by end users. To overcome these obstacles, dedicated network m
The analysis and design of a millimeter-wave passive balun on silicon substrate with small size and good balance is presented. The reason for the imbalance of the balun is analyzed and a novel method using two grounded T bars beneath the coupled lines to tune the balance is proposed. The balun was fabricated in a 65 nm CMOS process, by using broadside coupled lines with small separation, the lengt
As a part of the LDTA 2011 Tool Challenge, we implemented a compiler for the language Oberon-0 using the metacompilation tool JastAdd. In this paper, we report on this implementation, and reflect on aspects of it such as ease of use, modularity, and safety.
Gm-C filters suffer from limited dynamic range due to a trade-off between noise and linearity in OTA design. This paper therefore presents a filter with a linearization technique to break this trade-off. This technique is demonstrated by a low power 4th order 10MHz Butterworth Gm-C low pass filter. The filter was implemented in 65nm CMOS technology with a core area of 0.19mm2 and a total current c
Abstract in UndeterminedThe radio channels between nodes of an indoor peer-to-peer network show specific fast fading characteristics. Depending on the mobility and on the scattering properties of the environment, different kinds of fading distributions can occur: Ricean fading between static nodes, but also Rayleigh or even double-Rayleigh fading between mobile nodes. We investigate fast fading in
In the paper we consider a commonly known network design problem with demand restoration assuming stub release. No compact linear programming (LP) formulation for the problem is known, and all known non-compact LP formulations of the problem require NP-hard path generation (pricing). Therefore, the problem itself is suspected to be NP-hard - this, however, is not actually known. The main result of
Reference attributed grammars (RAGs) extend Knuth’s attribute grammars with references. These references can be used to extend the abstract syntax tree to a graph. We investigate how RAGs can be used for implementing tools for visual languages. Programs in those languages can often be expressed as graphs.
Background. Software engineering is in search for general principles that apply across contexts, for example to help guide software quality assurance. Fenton and Ohlsson presented such observations on fault distributions, which have been replicated once. Objectives.We intend to replicate their study a second time in a new environment. Method.We conducted a close replication, collecting defect data
This paper presents a low voltage continuous-time delta-sigma modulator (DSM) intended for the receiver of an ultra-low-power radio. The DSM features a 2nd-order loop filter implemented with a single operational amplifier to reduce the power consumption. Furthermore, a 4-bit quantizer is used to achieve high resolution while keeping the sampling frequency low. The quantizer is realized using the s
Context: Test driven development (TDD) has been extensively researched and compared to traditional approaches (test last development, TLD). Existing literature reviews show varying results for TDD. Objective: This study investigates how the conclusions of existing literature reviews change when taking two study quality dimension into account, namely rigor and relevance. Method: In this study a sys
We consider weighted sequence spaces on N with increasing weights. Given a fixed integer k and a Hankel operator Gamma on such a space, we show that the kth singular vector generates an analytic function with precisely k zeroes in the unit disc, in analogy with the classical AAK-theory of Hardy spaces. We also provide information on the structure of the singular spectrum for Hankel operators, appl
Context: Coping with rapid requirements change is crucial for staying competitive in the software business. Frequently changing customer needs and fierce competition are typical drivers of rapid requirements evolution resulting in requirements obsolescence even before project completion. Objective: Although the obsolete requirements phenomenon and the implications of not addressing them are known,
We consider the effect of signaling rate (baud rate) on the information rate of single carrier linear transmission systems with Gaussian inputs. Several different communication scenarios are investigated: correlated or uncorrelated symbols, a fixed modulation pulse or a modulation pulse varying with the signaling rate and frequency selective or flat channels. For uncorrelated symbols, we show that
Abstract in UndeterminedFaster-than-Nyquist (FTN) signaling is a method of improving bandwidth efficiency by transmitting information beyond Nyquist's orthogonality limit for interference free transmission. Previously have theoretically established that FTN can provide improved bandwidth efficiency. However, this comes at the cost of higher decoding complexity at the receiver. Our work has evaluat
Model order selection is an important element in system identification. It is well known that common model order selection methods such as Akaike’s information criterion (AIC) and Bayesian’s information criterion (BIC) neglect relevant information that is available in models of order different from the one chosen. In this paper the model order selection problem for receivers similar to those found
Background: Software ecosystems emerged as means for several actors to jointly provide more value to the market than any of them can do on its own. Recently, software ecosystems are more often used to support the development of hardware-dependent solutions. Objectives: This work aims at studying barriers and bridges to participation in an ecosystem with substantial hardware dependencies. Method: W
Regression testing is verifying that previously functioning software remains after a change. With the goal of finding a basis for further research in a joint industry-academia research project, we conducted a systematic review of empirical evaluations of regression test selection techniques. We identified 27 papers reporting 36 empirical studies, 21 experiments and 15 case studies. In total 28 tec
