摘要:

Consideration is given to the possibility of treating the radio spectrum as a tradable commodity and using market forces to assist the smoother and more efficient exploitation of the spectrum. The need to invest in training and to increase the supply of r.f. engineers with enhanced status is emphasized. Co-operation towards open standards which will favour the creation of a large European market served by European technology is stressed.

DOI:10.1049/jiere.1986.0063

出版商:IERE    

年代:1986

数据来源: IET

摘要:

A methodology is presented for the hierarchical, constructionally correct specification of digital controllers. It allows easy adaptation to architectural changes and straightforward preparation of documentation. Means are discussed for the rapid realization of the state diagram specification with efficient use of silicon, thus paving the way to general-purpose silicon compilation.

DOI:10.1049/jiere.1986.0064

出版商:IERE    

年代:1986

数据来源: IET

摘要:

The use of data compression schemes is in many cases of great importance when images are to be transmitted. Compression methods that exploit spatial and temporal statistical dependencies in an image frame or an image sequence have been suggested. This work comprises a new intraframe compression technique which combines a classification algorithm and a transform coding to obtain significantly higher compression ratios than obtained by transform coding alone. Some results obtained by the scheme are presented and their evaluation is discussed.

DOI:10.1049/jiere.1986.0065

出版商:IERE    

年代:1986

数据来源: IET

摘要:

This paper proposes the introduction of an Abort function for terminating unwanted retransmission in the Digital Access Signalling System No. 1 (DASS) protocol in use by British Telecom in the Integrated Digital Access (IDA) Pilot Service. By using this additional function it is shown how the system performance is subject to a worthwhile improvement.

DOI:10.1049/jiere.1986.0066

出版商:IERE    

年代:1986

数据来源: IET

摘要:

A mutual convertibility relationship between 50% duty cycle duobinary and minimum bandwidth (MB) dicode signals is identified through the spectral inversion of either signal by means of multiplication by a sinusoidal waveform of frequency equal to half the data bit rate and sharp bandlimiting at the Nyquist frequency. A signalling technique is described in which the mutual convertibility principle is used in order to convert a transmitted MB dicode signal into nonminimum bandwidth (NMB) dicode form at the signal destination for data recovery purposes.Drawings of relevant waveforms and spectra obtained from a special-purpose computer simulation verify the basic concept. The evidence obtained from a practical implementation of the MB dicode signalling technique shows that both MB dicode signals and their duobinary counterparts can be converted to NMB dicode form having an error performance within 1.5 dB of the optimum obtainable for Class 1 partial response (PR) signals, without recourse to decision feedback equalization (DFE) at the signal destination.

DOI:10.1049/jiere.1986.0067

出版商:IERE    

年代:1986

数据来源: IET

摘要:

The waveform at an inductive reproduce head of a digital magnetic recording system is a differentiated representation of the magnetic transition. Detection of the transition can be by zero-crossing detection when the head waveform is either further differentiated, or integrated to approximate the original flux pattern. For an integrating channel d.c. equalization is also required. The effect of pulse slimming, d.c. equalization, noise and pulse height variation is examined for both systems, from which it is concluded that an integrating channel has advantages provided that pulse height variations are small.

DOI:10.1049/jiere.1986.0068

出版商:IERE    

年代:1986

数据来源: IET