While the field of MIMO transmission has been explored over the past decade mainly theoretically, relatively few results exist on how these transmissions perform over realistic, imperfect channels. The reason for this is that measurement equipment is expensive, difficult to obtain, and often inflexible when a multitude of transmission parameters are of interest. This paper presents a flexible testbed developed to examine MIMO algorithms and channel models described in literature by transmitting data at 2.45 GHz through real, physical channels, supporting simultaneously four transmit and four receive antennas. Operation is performed directly from Matlab allowing for a cornucopia of real-world experiments with minimum effort. Examples measuring bit error rates on space-time block codes are provided in the paper.
We present an integrated 2:1 multiplexer and a companion 1:2 demultiplexer in CMOS. Both integrated circuits (ICs) operate up to a bit rate of 40 Gb/s. The 2:1 multiplexer features two in-phase data inputs which are achieved by a master-slave flip-flop and a master-slave-master flip-flop. Current-mode logic is used because of the higher speed compared to static CMOS and the robustness against common-mode disturbances. The multiplexer uses no output buffer and directly drives the 50-environment. An inductance connected in series to the output in combination with shunt peaking is used to enhance the bandwidth of the multiplexer. Fully symmetric on-chip inductors are used for peaking. The inductors are mutually coupled to save chip area. Lumped equivalent models of both peaking inductors allow optimization of the circuit. The ICs are fabricated in a 120-nm standard CMOS technology and use 1.5-V supply voltage. Measured eye diagrams of both ICs demonstrate their performance.
Abstract. BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V≈ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence "Constellation") from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria), are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies Spaceflight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency.Each BRITE instrument has a wide field of view (≈ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 x 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite.BRITE-Constellation will primarily measure p-and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell Diagram for stars brighter than magV=4 from which the BRITE-Constellation sample will be selected is shown in Fig. 1. This sample falls into two principal classes of stars:(1) Hot luminous H-burning stars (O to F stars). Analyses of OB star variability have the potential to help solve two outstanding problems: the sizes of convective (mixed) cores in massive stars and the influence of rapid rotation on their structure and evolution.(2) Cool luminous stars (AGB stars, cool giants and cool supergiants). Measurements of the † Member of the BRITE-Constellation Executive Science Team (BEST)
Abstract-Conventional RFID (radio frequency identification) systems operating at one single carrier frequency can hardly handle the great variety of shapes and materials that occur in products and packaging. In this contribution a dual-band antenna is presented that allows operation in the 13.56 MHz band as well as in the 868 MHz band. This provides two options to establish a data link to each object equipped with a dual-band RFID tag. The credit-card sized antenna consists of a very thin copperplated polyimide substrate that is flexible and can be integrated into packaging. Measurements revealed that the antenna provides a quality factor of 54 in the 13.56 MHz band and a gain of −4.69 dBi in the 868 MHz band.
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