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Communications, Radar and Signal Processing, IEE Proceedings F

Issue 2 • Date April 1980

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Displaying Results 1 - 13 of 13
  • Editorial: Special issue on advanced signal processing

    Page(s): 65 - 66
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    Freely Available from IEEE
  • Some philosophical aspects of signal processing

    Page(s): 67 - 75
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    Signal processing is viewed as a succession of conformal mappings to match the data to appropriate aspects of the signal, the noise/interference environment, the propagation medium or the intended ultimate use of the received data. These mappings are found to be subject to certain fundamental limiting equations. From this approach, a number of general design guidelines are adduced. The limiting inequalities and design guidelines are then justified a little more formally. The paper concludes with some examples and discussion of the practical application of these principles. View full abstract»

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  • Design and application of real-time spectrum-analyser systems

    Page(s): 76 - 91
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    The basis of spectrum analysis in Fourier transformation is briefly examined and the principles which can be applied in determining the spectral distribution of energy considered. Classes of analysers are distinguished that operate by frequency filtering and by time-domain processing; the latter being subdivided into direct linear methods depending on dispersive components, indirect or correlation methods, methods using complex Fourier transformation, and nonlinear simplified methods useful when the signal has known characteristics. The implementations and applications selected for description are intended to convey the importance of recent developments in s.a.w., digital, c.c.d. and optical technologies. View full abstract»

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  • Signal processing using surface-acoustic-wave and digital components

    Page(s): 92 - 98
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    The high performance of currently available digital components now permits the efficient coupling of surface-acoustic-wave and digital technologies. Hybrid circuits can be built which benefit from both the flexibility of the digital circuits and the high processing speed of the s.a.w. devices. Further, such circuits offer reduced volume and reduced power consumption. The compatibility of these two technologies, the resulting advantages and the coupling methods are discussed. System examples are presented which relate to the sonar and the radar fields ¿¿ pulse compression, beam forming, 2-dimensional analysis, spectrum analysis and correlation processing. View full abstract»

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  • Microprogrammable arithmetic element and its applications to digital signal processing

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    This paper describes a microprogrammable arithmetic element (m.a.e.) which has been designed as an integrated circuit on a high-speed bipolar process using emitter coupled logic (e.c.l.). Although the m.a.e., which contains a multiplier and adder, is a general-purpose computing device, it is ideally suited to a variety of digital signal processing (d.s.p.) applications such as discrete Fourier transforms, correlators, digital filters, etc. After a brief introduction to d.s.p. systems, some applications of the m.a.e. are discussed in detail. The m.a.e. forms part of a d.s.p. chip set which also includes a pair of integrated circuits. These have been produced by using e.c.l. programmable logic arrays (p.l.a.s); they decode a conventional binary sequence into the various addressing sequences required by a radix-2 decimation-in-time f.f.t. algorithm. In the past, the sheer cost and complexity of d.s.p. systems has restricted the system designers to make use of minimum hardware configurations in order to produce a system of reasonable size. However, such design philosophy has to be reviewed in the light of l.s.i. technology which has provided cheaper and bigger memory systems, apart from other l.s.i. building blocks. This point has been stressed by considering the design of an f.f.t. system. View full abstract»

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  • S.A.W. filters: some case histories

    Page(s): 107 - 117
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    The paper presents the background to s.a.w. (surface-acoustic-wave) filter design by discussion of both the basic consideration and the second-order design problems. The state of the art in filters available from a production activity is described by reference to three examples: the t.v. filter, the c.a.t.v. filter and some radar filters. In each case, the important criteria are discussed and their impact on the design detail is stressed. The future direction of s.a.w. filter work is briefly reviewed for each example. View full abstract»

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  • Radar applications of s.a.w. dispersive filters

    Page(s): 118 - 124
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    Pulse-compression radars have been developed in several countries over a period in excess of twenty years. A great advance in the performance of such systems has been made possible with the development of the surface acoustic wave (s.a.w.) interdigital transducer (i.d.t.). In the paper, some recent advances in i.d.t. performance are presented against a background which demonstrates the basic consistency in design techniques for both linear-and nonlinear-chirp signals. Later Sections of the paper assess the range of performance now available and consider the ways in which ultimate system performance may be achieved in respect of Doppler shift, coherence, mismatch loss and dynamic range. View full abstract»

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  • Applications of c.c.d.s to sonar systems

    Page(s): 125 - 131
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    The characteristics of the charge-coupled device (c.c.d.) are such that it is destined to make a considerable impact on sonar design, particularly in the more compact and lower power applications. The speed of operation and overall delay times available make it eminently suitable for beam forming and a wide range of transversal filter applications over the complete spread of sonar frequencies. Furthermore, the direct analogue sample operation and low power consumption are attractive features when space is at a premium. The paper describes some practical cases of the application of c.c.d.s to sonar, illustrating the advantages of such devices for beam forming, pulse compression and spectral analysis. View full abstract»

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  • Book review: Teletext and Viewdata

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    Freely Available from IEEE
  • Channel vocoder based on c.c.d. discrete-Fourier-transform processors

    Page(s): 132 - 143
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    This paper investigates how charge-coupled-device (c.c.d) modules could be applied in an alternative implementation of the now established channel vocoder. The objective is to demonstrate the potential of c.c.d. technology in the realisation of low-cost low-power speech processors. In this proposed implementation, the central processor is based on a c.c.d. discrete Fourier transform (d.f.t.) algorithm which is multiplexed to provide spectral data for channel compression and cepstral data for pitch detection. Synthetic speech is reconstructed from zero phase impulse responses by a novel convolution technique designed to eliminate frame discontinuities. Extensive computer simulations have been used to determine a suitable hardware architecture and this is compared to a c.c.d. switched-capacitor parallel-filter-bank channel vocoder in terms of performance and total chip count. It is concluded that a very small c.c.d. channel vocoder configuration could be based on a combination of the d.f.t. analyser and the filter-bank synthesiser. View full abstract»

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  • Charge-coupled devices for use in electronically-focused ultrasonic imaging systems

    Page(s): 144 - 154
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    Pulse-echo ultrasonic imaging techniques make possible the dynamic visualisation and characterisation of many soft-tissue structures with no known patient risk; however, the extraction of this information requires an ultrasonic imaging system capable of producing a high-resolution image over a sizeable field of view in real time. This paper describes the development of the cascade charge-coupled device (C3D) designed specifically for electronically-focused ultrasonic imaging systems. The C3D lens described here further enhances the desirability of such systems because the delay-line hardware needed to focus and beam steer a linear array of piezoelectric transducers is reduced to a single l.s.i. device, and because clock-frequency control does not require individual control signals for each transducer channel and therefore greatly limits the amount of external circuitry necessary to support the imaging system. The analysis of the fundamental limits of the C3D approach to ultrasonic imaging includes the effects of the asynchronous transfer of charge between sections operating at different clock frequencies, with emphasis on the impact of this process on the time-delay accuracy of the C3D lens and on the maximum level of sidelobe suppression. The first-generation C3D lens has been fabricated and tested in a static water tank. These measurements indicate that the lens produces near-theoretical lateral resolution as predicted by the aperture theory of linear arrays. Based on preliminary results, a second-generation device is proposed whose additional capabilities would include full interpolation of the field of view for a scan-line-free image presentation and on-chip apodisation to obtain higher degrees of sidelobe suppression. View full abstract»

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  • Synthetic-aperture-radar real-time processing

    Page(s): 155 - 162
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    The possibility of performing synthetic-aperture-radar (s.a.r.) processing on board a satellite is of current interest to the European Space Agency (ESA). A brief outline of the fundamental principles and capabilities of s.a.r. is given, and several real-time processor configurations are discussed, in terms of their suitability for use on board a satellite. In particular, the applicability of new signal-processing technologies is considered, since only these can provide suitable devices for the implementation of an on-board processor. View full abstract»

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  • Receivers for the NAVSTAR global positioning system

    Page(s): 163 - 167
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    The NAVSTAR global positioning system (g.p.s.) is being actively developed by the USA and is likely to become operational for both civilian and military users in the mid-1980s. Accuracy of position in three dimensions of afew metres and velocity within 0.1 m/s is predicted. The user equipment, essentially a receiver and an antenna, will employ a considerable volume of signal-processing hardware and software. This paper aims to provide for the signal-processing community some basic understanding of the system outline and its operation as a navigation aid; a typical receiver outline is broken into a number of units whose operation is described with some emphasis on the signal-processing aspects. Areas in which improved signal-processing methods could contribute to improved performance, particularly in interference conditions, are examined. The potential of the antenna in improving user equipment performance by providing angular selectivity against interference is examined briefly; results from the literature indicate improvement of up to 30dB. New signal-processing technologies, surface-accoustic-wave devices and c.c.d.s are likely to contribute to g.p.s receiver development in both frequency-generation and signal-processing areas. View full abstract»

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Aims & Scope

The latest version of this title is Radar, Sonar & Navigation, IET.

Full Aims & Scope