摘要:

Aerials which employ the conductors of the rear-window heaters of motor vehicles have been developed recently for broadcast reception at low and medium frequencies and v.h.f. This paper describes the techniques used to optimize their performance and presents results from a production saloon car. An experimental rear-window heater aerial for transmitting and receiving in the v.h.f. low band is described and the conflicting constraints of efficiency, bandwidth, power-handling and cost are discussed. Test results are presented for a hatch-back vehicle and compared with those from roof and wing-mounted whip aerials.

DOI:10.1049/jiere.1986.0087

出版商:IERE    

年代:1986

数据来源: IET

摘要:

A Data Flow design methodology for CAD (Software and Hardware) which treats hardware and software in a unified way, is the basis of the training at LINC. A set of PC-based CAD tools, to enforce the methodology, will be mounted as they become available. There will be a resident Data Flow methods and tools company and the intention is to interface the new tools to the more traditional CAD tools, for gate array and PCB layout. Generally the goal is to provide an Integrated Project Support Environment for the development of both the software and hardware of IT systems.

DOI:10.1049/jiere.1986.0088

出版商:IERE    

年代:1986

数据来源: IET

摘要:

This paper presents a status report on the development of standards enabling the interconnection and interworking of text and office systems. These standards are in the Application Layer of the ISO Reference Model for Open Systems Interconnection. The paper also introduces the principles underlying one of these standards known as the Office Document Architecture.

DOI:10.1049/jiere.1986.0090

出版商:IERE    

年代:1986

数据来源: IET

摘要:

The aim of this paper is to exactly evaluate the detection losses due to the sampling of a video pulse, in order to allow a trade-off between sensitivity and A/D converter speed. Both single-threshold detection (after coherent integration) and double threshold binary integration (moving window) are considered. The former case is analysed for both fixed and fluctuating targets. The largest sampling losses are found to occur for single threshold detection, fixed targets and large values (0.9–0.95) of the detection probability. For a sampling period equal to the pulsewidth 7the losses range between 2.5 dB and 3 dB. On decreasing the sampling interval the losses quickly reduce: when two samples per pulse are taken, the losses are very close to 0.5 dB. The main application is in the radar area.

DOI:10.1049/jiere.1986.0091

出版商:IERE    

年代:1986

数据来源: IET

摘要:

This paper proposes a multi-media packet protocol for realizing packetized data, voice, and video communications in a packet switched network. Requirements for such multi-media packet communications services are greatly manifold, ranging from low to high speed, low to high grade service quality or simple to sophisticated service facilities, depending on the communications media.The proposed protocol provides high-speed transmission function with priority rules, transmission error correcting functions and packet transit delay indicating functions for voice and video communications, in addition to the X. 25 protocol functions for data commmunications. Also, a newlylayered structure for this protocol is presented, in which functional overlaps among layers are eliminated and common functions used by every medium are arranged into lower layers.

DOI:10.1049/jiere.1986.0092

出版商:IERE    

年代:1986

数据来源: IET

摘要:

The possibility of utilizing frequency-hopped multilevel frequency shift keying (FH-MFSK) techniques for data transmission corrupted by additive white Gaussian noise (AWGN) is discussed. FH-MFSK is one of the many techniques used in spread spectrum systems and is a combination of frequency-hopping and time-hopping. In this system many users share a common frequency band using code-divisionmultiplexing. Each user is assigned an address and the message is modulated on to the address. The receiver, knowing the address, decodes the received signal and extracts the message. A microprocessor supervised experimental FH-MFSK system has been constructed and used to perform error-rate measurements in the presence of AWGN with deleted and delayed sample effects. Its capability for multi-user applications has been determined theoretically. The results show that FH-MFSK is a suitable technique for data transmission in the presence of AWGN.

DOI:10.1049/jiere.1986.0093

出版商:IERE    

年代:1986

数据来源: IET