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The baseband and intermediate frequency (IF) frequency modulated continuous wave (FMCW) radar receiver topologies are compared on the bases of receiver nonlinearity, time domain interferometry, receiver noise and demodulator port isolation. It is shown that an IF receiver is capable of suppressing distortions, where the same nonlinearity would result in a baseband (or zero-IF) receiver detecting false...
The use of high power jammers on vehicles for Improvised Explosive Device (IED) detonation prevention and strategic enemy communications jamming, allows for high levels of noise and interference to couple from the jamming systems to the co-located on-board communications radio receivers. The high levels of jammer noise desensitise communication receivers and render them less effective. The use of...
Considering the imminent migration of services to the Ka- and Q-bands, a payload dedicated to propagation measurements in these bands has become available from the Alphasat satellite under the coordination of the European Space Agency. This has strongly motivated the formation of many measurement campaigns across Europe in an effort to enhance the scientific databases with new, more reliable propagation...
The paper deals with research of energy characteristics of multilevel modulation techniques for modern broadband radio systems. The problems of modeling and analysis of digital data transmission channel are considered
This paper proposes a comprehensive analytical model for deriving receiver sensitivity and minimum transmit power in 802.15.6 wireless body area networks (WBANs). Formulas derived for both receiver sensitivity and minimum transmit power are determined by the signal-to-noise (SNR) ratio at the output port of the receiver, the noise floor, and the receiver noise figure. Minimum transmit power also depends...
In this contribution a novel method is discussed that is of practical use for analyzing the electromagnetic compatibility behavior of electronic systems. The aim is to develop an efficient technique that mimics radiated immunity and emission tests in the presence of multiple non-collocated noise sources in simulation. The proposed method is simple in that it only relies on the simulated (or measured)...
Usually, imaging and measurement using ultrasound employs the application of single pulse signals for probing. Despite low correlation sidelobes and wide bandwidth which contribute to the good temporal resolution such single pulses have low energy. If material attenuation and scattering are high, or application is air-coupled, signal losses are high and signal-to-noise ratio is low. Spread spectrum...
We describe the developments of a propagation receiver for the Alphasat Q-band copolar beacon that is expected to be operational from April 2015. The receiver link budget and the expected attenuation dynamic range are presented. The RF hardware and a simplified approach to one axis only antenna pointing system solution are detailed. Solutions to acquire and detect the beacon signal are discussed....
The Atacama Millimeter/Sub-millimeter Array (ALMA) is one of the most powerful telescopes built to date. All the receivers that cover the 10 frequency bands (35–950 GHz) in ALMA must comply with stringent requirements in order to perform astronomical observations, in particular, low noise temperature and high aperture efficiency. The ALMA band 1 receiver optics (35–52 GHz) are composed of a corrugated...
In this paper, a measurement procedure to capture properly the electromagnetic fields generated by radiated transient interferences is described. Measuring this type of impulsive noise out of the measurements defined at the EMC standards is essential to acquire the main parameters of the interferences. In order to protect the digital communication systems against radiated transients, the essential...
This paper presents a wireline receiver design of CMOS I/O at 10-Gb/s data rate. A power efficient continuous-time linear equalizer (CTLE) and 1-tap lookahead decision feedback equalizer (DFE) are designed and implemented in a 45 nm CMOS technology. The DFE employs a sampler including a current injection section that makes no use of summer as a separated block. In addition, cascode structure increases...
Wireless communication is vulnerable to intentional electromagnetic interference, and therefore it is important to understand the interfering mechanisms. In this paper we investigate the effect of pulsed interference - as compared to continuous interference - on a receiver of digital amplitude modulated signals. To correctly receive the signals, a threshold estimate has to be computed for the proper...
In HF (3–30 MHz) communications the ambient electromagnetic background noise or ‘radio noise’ generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the influence of the measurement antenna on the measurement results. A novel method to compare the polarization...
A low-noise cryogenic phased array feed (PAF) is in development for the Green Bank Telescope (GBT). The feed consists of electrically small elements tuned to operate near 1.4 GHz and optimized for active impedance matching to cooled front end low noise amplifiers (LNAs). A prototype cryogenic PAF with analog fiber link, down-converters and streaming data acquisition system was recently tested on the...
In this paper we provide a review for the time domain analysis of the normalized timing error dynamics of a wireless receiver Early-Late tracking loop (A loop that controls the timing of a pseudo-noise code that is locally generated in the receiver). This review shows that the timing error dynamics modelling is cumbersome and can be simplified by linearizing the tracking loop. The linearization assumption...
Simultaneous transmit and receive systems (STAR) are proposed to double the spectral efficiency and enhance spectrum utilization in the traditional microwave band. A major problem is high power self-interference (SI) due to the proximity of the transmit and receive antennas. In this paper, we propose to significantly improve system-level performance using a novel high isolation RF front-end based...
We discuss the theory and implementation of phased array receivers in the focal plane of a telescope as applied to the mm-wave band. Simulated performance and construction details are given for a 64 element, 70–95 GHz array receiver for use on the Green Bank Telescope (GBT).
The Cognitive Multiple Access Z-Interference Channel consists of a MAC channel that receives interference from an external transmitter. In a previous work we studied this model where both MAC users are cognitive and showed that an encoding scheme based on Dirty Paper coding attains the capacity region for the Gaussian case. In this work we assume that only one MAC user is cognitive and show that the...
Signal estimation in MIMO communications typically suffers from performance degradations due to imperfect channel state information (CSI). Traditional robustification schemes rely on assumptions about the model uncertainty and may result in conservative performance. We introduce a rank-reduction approach that enhances the performance in training-based applications. A sequence of reduced-rank channel...
This paper addresses optimal mean-square performance for multiple-input multiple-output (MIMO) linear time invariant (LTI) systems subject to exogenous noise and communication losses between the plant and controller. First we derive linear matrix inequalities (LMIs) for analysis of mean-square stability and performance, then we show how a pair of semidefinite programs (SDPs) can be used to convexly...
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