摘要:

The separation of additive, finite, discrete stochastic signals using the concept of the generalised ideal filter is considered. The autocorrelation of each component signal is assumed to be known. The conditions for existence of such a filter are determined, and an algorithm is developed for sequential implementation of the filter, updating the output with each input sample with simultaneous checking of the separability conditions.

DOI:10.1049/ip-f-1.1981.0001

出版商:IEE    

年代:1981

数据来源: IET

摘要:

In the paper it is shown that the Chinese remainder theorem when coupled with a modification of Winograd's method can be used to compute Fourier-like transforms overGF(2m), wherem=2, 3,…, 8. These new transform techniques are to decode Reed-Solomon codes of block length 2m−1. The results are shown to be more efficient than the more conventional method.

DOI:10.1049/ip-f-1.1981.0002

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The use of codes in forward error correction and decision feedback schemes is analysed. Various comparisons of the two types of error control scheme are undertaken when finite and infinite repetitions are possible and when the feedback channel can be considered noisy or noiseless. These comparisons are based on the consideration of both the average information bit error probability and transmission efficiency to obtain the overall effectiveness of the error control schemes.

DOI:10.1049/ip-f-1.1981.0003

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper describes some simple and easily calculated measures of the amplitude distortion introduced by an unknown channel. These can be used to assess maximum-likelihood performance without the need for computer simulation.

DOI:10.1049/ip-f-1.1981.0004

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The optimum linear multiple transmitting and receiving filters are determined for noisy multiple-channel systems using a criterion of minimum output noise variance under the constraints of zero intersymbol interference (ISI) and interchannel interference and of fixed transmitting power. The optimum transmitter appears to generate orthogonal vector functions. For these vector functions the cascade connection of the multiple channel and its multiple matched filter behaves like noninterfering channels (NIC). In the optimum system the ISI is eliminated per NIC by a transversal filter.

DOI:10.1049/ip-f-1.1981.0005

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper describes some simple techniques for estimating the sampled impulse response of a time-varying channel, in the case where a maximum-likelihood detector is used at the receiver, and where severe intersymbol interference is, from time to time, introduced into the received signal. The estimators are studied for the particular application of a synchronous serial data-transmission system operating at 2400 bit/s with a 4-level quadrature amplitude-modulated signal transmitted over a model of an HF radio link, the latter having two independent Rayleigh-fading sky waves and frequency spreads of 1/2;, 1 and 2 Hz. Results of computer simulation tests are presented, comparing the accuracies of the estimates of the channel given by the different estimators, and hence suggesting the most suitable estimator.

DOI:10.1049/ip-f-1.1981.0006

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Secondary surveillance radar (SSR) offers many advantages for air traffic control (ATC) compared to normal (or primary) radar including substantially lower cost and improved performance. Because of the increasing reliance being placed on SSR by ATC a number of the system problems associated with SSR are becoming less easily tolerated. The paper discusses these problems, which mainly arise from multipath and mutual interference effects, and proposes solutions.

DOI:10.1049/ip-f-1.1981.0007

出版商:IEE    

年代:1981

数据来源: IET

摘要:

In order to explore experimentally the design of speech transform coding schemes it is necessary to implement forward and inverse FFT processors of sufficient accuracy that their contribution to the total distortion, over and above that of the source digitisation, is negligible. In this way we ensure that examination of rate-distortion coding tradeoffs is not obscured by additional distortion in the analyser/synthesiser subsystem. Accordingly, forward and inverse FFT processors have been designed and constructed incorporating an overflow correction scheme previously only implemented in software, which maximises their dynamic range. Objective measurements indicate a 49dB dynamic range for the analyser/synthesiser combination, and subjective tests confirm the negligibility of the concomitant distortion.

DOI:10.1049/ip-f-1.1981.0008

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper describes a colour display and data processing system for use on conventional weather radars. It also discusses aspects of the meteorological echo characteristics, the implications on data processing equipment, and the implementation adopted in the Plessey Colourscan equipment to meet the requirements for quantitative analysis and storm warning applications.

DOI:10.1049/ip-f-1.1981.0009

出版商:IEE    

年代:1981

数据来源: IET