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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
Multi-user MIMO offers big advantages over conventional point-to-point MIMO: it works with cheap single-antenna terminals, a rich scattering environment is not required, and resource allocation is simplified because every active terminal utilizes all of the time-frequency bins. However, multi-user MIMO, as originally envisioned, with roughly equal numbers of service antennas and terminals and freq
This paper presents a noise cancelling 0.7– 3.8GHz receiver front-end implemented in 65nm technology. The circuit has a main path consisting of a high input impedance gm-stage, current-mode passive mixers and baseband amplifiers, where the input match is provided by frequency translational negative feedback from baseband to RF input. An auxiliary path with tunable gain is introduced to cancel nois
We compare the technique of using the orbital angular momentum (OAM) of radio waves for generating multiple channels in a radio communication scenario with traditional multiple-in-multiple-out (MIMO) communication methods. We demonstrate that, for certain array configurations in free space, traditional MIMO theory leads to eigen-modes identical to the OAM states. From this we conclude that communi
Unit verification, including software inspections and unit tests, is usually the first code verification phase in the software development process. However, principles of unit verification are weakly explored, mostly due to the lack of data, since unit verification data are rarely systematically collected and only a few studies have been published with such data from industry. Therefore, we explor
Low-complex and low power non-coherent energy detector (ED) is interesting for low data rate impulse radio (IR) ultra wideband (UWB) systems but, compared to coherent receivers, it suffers from a loss in performance due to low signal-to-noise ratio (SNR) at the detector. In addition, the performance of an ED strongly depends on the integration interval (window size) of the integrator and the window
Despite recent attempts to relax the phase-noise demands on voltage-controlled oscillators (VCOs) for cellular communications [1], mainstream radios require harmonic VCOs capable of a very low phase noise with moderate power consumption, associated to a large tuning range (TR) and a high insensitivity to interfering signals. Ideally, the TR should be in excess of one octave, since this allows the
We perform a minimum distance analysis of a class of two-dimensional intersymbol interference (ISI) channels applicable to multitrack magnetic recording and orthogonal frequency division multiplex transmission systems. Exact minimum distance for a wide class of ISI responses is derived. The fundamental analytical technique is to transform the channel into an equivalent minimum phase channel. The r
The popularity of Open Source Software (OSS) has increased the interest in using it in safety critical applications. The aim of this study is to review research carried out on usage of open source code in development of safety-critical software and systems. We conducted a systematic mapping study through searches in library databases and manual identification of articles from open source conferenc
This paper presents a 2.45 GHz wake-up receiver front-end intended for use in sensor networks, and is designed to receive data modulated with on-off-keying. Manufactured in 65 nm CMOS it employs an uncertain IF structure with three phase passive mixer and high gain amplifier chain. With the modulation frequency response tailored to the detector behaviour, it achieves a sensitivity of -88 dBm at BE
Abstract in UndeterminedYou may think that your requirements engineering process is fairly limited and currently not too complex to manage. Or you may be right in the middle of a storm of requirements where it is impossible to manage even the most important ones comprehensively. If you are in the former situation, it may be dangerous to relax as many successful software-intensive products have a t
