摘要:

A method is described for specifying the control flow of a digital system by means of either programming language or graphical constructs. The system is constrained to obey the principles of structured programming and particular attention has been given to specifying concurrent structures (pipeline and overlap structures) using these principles. A worked example showing the use of these design methods is given.

DOI:10.1049/ij-ecs.1977.0001

出版商:IEE    

年代:1977

数据来源: IET

摘要:

The paper is about the design of a novel speech processor and its successful incorporation in a vibrotactile speech training aid for the deaf. The introduction makes clear the particular difficulties and needs of the deaf child who is learning to speak. The discussion shows that to help with the deaf child's difficulty with mimicry the technologist must enable the child to sense and compare patterns of articulator configurations. It is suggested that the vocal gestures will be monitored most easily if the speech processor operates in such a way as to ignore variations in speech intensity. An explanation is given of a novel amplitude insensitive filtering system which employs a bank of high-pass filters. A particular requirement of the system is for the measurement of the ratio of two voltages each of which can vary over a wide dynamic range; a circuit for this is presented. Although the discussion focuses on the application of the frequency-analysis system to speech processing the theoretical treatment facilitates the evaluation of the system's potential for processing other signals.

DOI:10.1049/ij-ecs.1977.0002

出版商:IEE    

年代:1977

数据来源: IET

摘要:

A laser ceilometer is an optical radar system which ascertains the height of the base of cloud by measuring the time taken for a pulse of light to travel from the transmitter to the cloud base and to return to the receiver. The single field unit houses the GaAs laser optical transmitter, optical receiver and the signal detection and processing electronics. The height of the base of the cloud is processed digitally within the field unit. The equipment has been designed to overcome the various limitations of earlier ceilometers, such as the base-line requirement, moving mechanical parts, dangers from high-powered lasers and constant maintenance to ensure alignment. Proven modern technology is employed throughout. The range of cloud-base heights over which the equipment operates is 30–1455 m. The equipment is modular, thus greatly easing maintenance. Theoretical considerations and constructional details will be discussed. The ceilometer has been compared at an airport with a cloud-base recorder operated by the British Meteorological Office. The ceilometer worked well within its specification in this operational environment, and these results will be presented

DOI:10.1049/ij-ecs.1977.0003

出版商:IEE    

年代:1977

数据来源: IET

摘要:

The Marconi Company, with the support of the Ship and Marine Technology Requirements Board of the Department of Industry, has developed an acoustic positioning system for floating vessels. Among other principles used, a variant of the superhet' receiver is employed in the task of detecting acoustic signals in the sea. The end product is a method of extremely accurate local navigation of surface vessels relative to the ocean floor. Since 1962, in this and other applications, the system has demonstrated its abilities of reliable detection if there are multiple signals in the presence of background noise, and accurate timing of signal arrival and freedom from false recognitions which are generated either by noise or crosscoupling between channels. This, the most recent application, saw its inception with the upsurge in offshore exploration when dynamic positioning of ships became a desirable facility.

DOI:10.1049/ij-ecs.1977.0004

出版商:IEE    

年代:1977

数据来源: IET

摘要:

A new type of negabinary arithmetic algorithms/circuits for negative negabinary addition, polarisation and negabinary addition, subtraction and comparison are presented, using binary arithmetic algorithms/circuits. They use standard m.s.i. binary adders/a.l.u. and look-ahead carry generators and are very simple compared to the circuits proposed earlier. Also, this technique is suitable for fast operation.

DOI:10.1049/ij-ecs.1977.0005

出版商:IEE    

年代:1977

数据来源: IET

摘要:

A new circuit called a current follower, is described. It may be used with voltage followers to replace operational amplifiers. The advantages are at high frequencies, where the operational amplifier is unsuitable because of its limited frequency response and slew rate. Basic applications for these purposes are given. An, analysis of the internal nonlinear equations of the designed linear circuit is given. The analysis of the linear model of this circuit shows a typical example of the application of the symbolic networkanalysis program Netform. Extremely short computation times are observed in a nontrivial situation, due to the newly implemented double sparse Laplace expansion (d.s.l.e.) method.

DOI:10.1049/ij-ecs.1977.0006

出版商:IEE    

年代:1977

数据来源: IET