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IEE Review

Issue 1 • Date Jan 2001

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Displaying Results 1 - 10 of 10
  • Controlling traffic with radio

    Page(s): 40 - 44
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    The author reviews the role of radio frequencies in the control of traffic and pedestrians. He discusses active control of traffic junctions based on vehicle actuated demands; implying a requirement for vehicles approaching junctions or waiting at junctions to be detected, and for that detection event to be notified to the junction controller. It is also desirable to know the direction of an approaching vehicle. The great advantage of this approach is that the junction control system can generate a sequence for the light signals which should optimise the prevailing traffic flow. Detectors use a wide range of frequencies within the electromagnetic spectrum, ranging from visible light range down to tens of kHz. Within the radio frequency range, and subject to the operating frequency used, traffic detection can be effected using either below ground or above-ground antennas. The author describes both of these systems and the frequencies used for the latter. The operation and implementation of these systems is then discussed View full abstract»

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  • Broad is the way [ultra-wideband technology]

    Page(s): 35 - 39
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    Ultrawideband (UWB) systems, which combine bandwidths in excess of 1 GHz with very low power spectral densities (PSDs), are currently attracting growing interest as a means of wresting additional capacity from the already heavily utilised store of wireless bandwidth. If the emissions from UWB devices are regulated to avoid causing significant interference to licensed services, then it becomes possible to allow UWB systems to operate on an unlicensed basis, enabling UWB technology to support a diverse range of applications. As yet, there are no regulations for UWB devices. However, the US is in the process of setting up a regulatory framework, while within Europe, where matters are not quite so far advanced, possible approaches to UWB regulation are under consideration. The author describes the basic principles and the role of regulation in determining the UWB devices destined for commercial deployment View full abstract»

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  • Mesh networks for broadband access

    Page(s): 17 - 22
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    Broadband wireless access systems must satisfy exacting technical and commercial requirements. In this paper, the author describes a novel approach that uses Internet-like routing to bridge the infamous `last mile' View full abstract»

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  • Have null, will fly [data tagging]

    Page(s): 31 - 34
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    This article is concerned exclusively with data tags which are machine readable and which do not require contact between the tag and the reader. Such devices are of considerable commercial interest, either because they speed up a data collection process, or because they provide a new function, or both. The goal of very low cost, vibration-free tagging was finally realised with SGL's 1995 invention of flying null (FN) technology. An FN data tag is the magnetic equivalent of an optical bar code. In the case of FN, however, the bars in the code are made from a very soft (low coercivity), high permeability, magnetic alloy, and the tag is read using a special magnetic reader. Very little material is required and there are no special packaging requirements, so FN tags can be made for a fraction of the cost of other tags. The reader is the key to the technology. It creates a narrow region of zero field (a null) in space, surrounded by regions where the field strength is sufficient to saturate the magnetic material used in the tag. In a typical implementation, it also applies a low-amplitude alternating magnetic field to the interrogation region, so that a soft magnetic element in the null region is driven into and out of saturation, thereby radiating harmonics of the interrogation frequency. These harmonics can be detected, and their time of occurrence related to the position of the element with respect to the null. In typical systems, a spatial resolution of better than 50 μm can be achieved for a reader-to-tag separation of many millimetres View full abstract»

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  • Something in the air [electronic nose]

    Page(s): 10 - 14
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    No electronic nose can match the capabilities of its human counterpart. But, as the author reports in this paper, advances in sensor technology are transforming the capabilities of the all-electric hooter View full abstract»

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  • Hybrid vigour [hybrid electric vehicles]

    Page(s): 25 - 28
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    In this paper, the author reports on the theory and practice behind cars powered by a combination of petrol engine and electric motor. The operating principles and future possibilities for hybrid electric vehicles are outlined View full abstract»

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