The evolution of HDTV in the work of the CCIR

The development of television system standards in the CIR (International Radio Consultative Committee) is reviewed. Background and results of the extraordinary meeting on high-definition television (HDTV) of CCIR Study Group II are presented. The arguments for a global studio standard for HDTV are examined as are the proposals for achieving this objective. The evolution toward digital systems and the preparation of emission/transmission standards is summarized. Cost, size, weight, and time frame are seen to be major constraints     

CCITT Recommendations on the ISDN: A Review

This paper gives a brief overview of the I-Series of Recommendations on the integrated services digital network (ISDN) developed by the International Telephone and Telegraph Consultative Committee (CCITT). This set of Recommendations is printed in the CCITT "Red Book." The I-Series Recommendations represent the first major step towards worldwide harmonization of the fast-growing digital network capabilities in support of multiservice (voice, data, and image) user applications. Over 25 different Recommendations set up standard guidelines and features for service capability, network architecture, and user-network interfaces in the ISDN.     

Multimedia multipoint teleconference system using the 7 kHz audiocoding standard at 64 kbit/s

The International Telegraph and Telephone Consultative Committee (CCITT) has recommended an algorithm to code wideband speech and music (i.e. 7-kHz audio) with 64 kb/s as an international standard (recommendation G.722). A multimedia multipoint teleconference system using the 7-kHz audio coding standard is discussed. System requirements for teleconferencing are examined, and control procedures for the system are examined. A system using digital leased circuits is presented, and the audio-bridging technique used in this system is discussed     

Regulatory Aspects of Digital Communications (Radio Frequency Considerations)

This paper describes the domestic and international rules, regulations, reports, and recommendations that have an impact on the design and operation of digital systems. The emphasis is on the technical and the radio frequency (RF) aspects, but nontechnical and baseband matters are mentioned briefly. Organizations discussed include the International Telecommunications Union (ITU), the International Telephone and Telegraph Consulatative Committee (CCITT), the International Radio Consultative Committee (CCIR), the Federal Communications Commission (FCC), and the Office of Telecommunications Policy/Interdepartment Radio Advisory Committee (OTP/IRAC).     

Signal level distributions and fading for a long over-water link at 5 GHz

Measurement results are presented for an 88-km multiple-diversity line-of-sight microwave link across the English Channel operating in the 4 to 5 GHz frequency range. Signal level and fade duration statistics derived from the measurements are compared with the applicable International Radio Consultative Committee (CCIR) models. Although signal level distributions are in fair agreement with CCIR predictions, the median fade duration tends to be shorter than values estimated from the CCIR model.     

Industrial application of HDTV

A summary is presented of the activities of an Interim Working Party (IWP 11/9), set up by the International Radio Consultative Committee (CCIR) to harmonize the standards being developed for HDTV broadcasting with nonbroadcasting HDTV applications. Imaging applications and characteristics across industries are examined. The discussion covers printing, cinema, electronic cinematography, computer applications, medical images, museums, expositions, education, and military and other special applications. Examples of hardware for nonbroadcast applications are considered     

Networking of networks: interworking according to OSI

The formal method of interworking networks in accordance with the overall open systems interconnection (OSI) effort being pursued by both the International Organization for Standardization (ISO) and the International Telegraph and Telephone Consultative Committee (CCITT) is described. The problem is introduced, the applicable OSI concepts are defined, and the basic architectural model for interworking and the resulting requirements on protocols, relaying, addressing, and routing are discussed. The problem of interworking from the perspective of the bottom four layers of the reference model (RM)-OSI is approached in a heuristic and informal fashion. The necessary background material is presented using a rigorous set of tools is developed by the work on the RM-OSI. The concepts of interworking are further developed. Conclusions and observations concerning ongoing work are presented     

Intelligent network overview

The International Consultative Committee for Telephone and Telegraph (CCITT) program of work that addresses global international intelligent network (IN) standards and a framework for the standardized evolution of IN are described. Bell Communication Research's (Bellcore's) IN work, referred to as the Advanced Intelligent Network (AIN), is also discussed in relation to the CCITT IN Recommendations. In addition, IN activities of the European Telecommunications Standards Institute (ETSI) and the Telecommunications Technology Committee (TTC) of Japan are described     

HDTV standards

An overview of relevant International Radio Consultative Committee (CCIR) activities in the area of high-definition television (HDTV) standardization is presented. The status of the CCIR standards with respect to chromaticity and signal format, picture characteristics, picture scanning characteristic, and analog and digital representation is discussed. It is concluded that the achievement of a single unambiguous parameter set requiring no quality impairing conversions in international program exchange remains doubtful     

Generalized cutoff rate of time- and frequency-selective fadingchannels

The generalized cutoff rate of time- and frequency-selective fading channels is evaluated for M-ary frequency-shift keying (MFSK) and M-ary differential phase-shift keying (MDPSK) modulation with soft decoding. The optimal signaling rate and code rate for dispersive channels are evaluated. The guard time effect, is used in multipath spread channels, is evaluated for frequency-selective channels, and the optimal combination of signaling rate, code rate, and guard time is presented. Special attention is given to CCIR (International Radio Consultative Committee) HF channel models     

The impact of G.826 [digital systems error performance]

The International Consultative Committee for Telephone and Telegraph (CCITT) recommendation G.826, the error performance recommendation for digital systems operating at or above the primary rate, is summarized. The relationship between block-based error performance parameters and the bit error rate (BER) is reviewed. The transition from the previous recommendation, G.821, to G.826 is discussed, including a brief statement of the main points found in G.826. The conversion of block-based error performance objectives (EPOs) to BER criteria is discussed in a nonmathematical way. The implications of G.826 and some conclusions are presented     

Frame relaying and the fast packet switching concepts and issues

High-speed networking based on frame relaying and fast packet switching are discussed, and the distinctions between the two technologies are clarified. Some of the recent International Consultative Committee for Telephone and Telegraph (CCITT) standards are examined, and the remaining issues for implementing these services are addressed. Particular attention is given to congestion control issues in ATM (asynchronous transfer mode) and frame relay networks. Some industry implementations are briefly reviewed     

Frequency dependence of microwave depolarization versus rain attenuation

Calculations using oblate spheroidal raindrops, as well as measured data, demonstrated that rain-induced cross polarization amplitude is inversely proportional to frequency from 10 to 30 GHz. Except for extremely low rain rates (leq2.5mm/h), the above frequency dependence has now been found to be true also for the more realistic (Pruppacher and Pitter shape) raindrops. Possible explanation for the misleading claim of inverse three-halves power frequency dependence was also explored. This clarification is presented to revise the frequency dependence of the International Radio Consultative Committee (CCIR) formula on rain-induced cross polarization versus attenuation.     

Improvement of a rain attenuation prediction method for terrestrial microwave links

An empirical model for predicting rain induced attenuation on terrestrial paths using effective path length is proposed. Comparison with the recently prediction method proposed by the International Radio Consultative Committee (CCIR) is made. It appears that our prediction method reveals good agreement with experimental data from different locations in the world.     

The ISO reference model entities

The functionalities and presently defined entities at the different levels of the Open Systems Interconnection reference model are discussed. An overview of standards activity by the International Organization for Standardisation (ISO), the Institute of Electrical and Electronics Engineers (IEEE), and the International Consultative Committee for Telephone and Telegraph (CCITT) is given. The ISO reference model and layer functions are described. Standards for the different layers are examined. Network security and naming and addressing issues, which were not covered by the basic reference model and earlier standards activities, are addressed. Two private-sector examples of OSI networks, the Manufacturing Automation Protocol (MAP) and the Technical Office Protocol (TOP), are considered     

OAM&P for ISDN basic access DSL based on ANSI physical layerstandards

The operations administration maintenance and provisioning (OAM&P) functions provided by the American National Standards Institute (ANSI) for the following standards are described: T1.601, a 2B1Q-based transmission system at the network side of the NT1; T1.605, the United States version of the International Consultative Committee for Telephone and Telegraph (CCITT) Rec. I.430; and T1.216, for management of the ISDN basic rate physical layer. System life-cycle costs are discussed. These consist of the total of hardware cost, line engineering and installation cost, lifetime maintenance costs, and lifetime operations costs. A complete list of the OAM&P functions provided in the August 1990 draft proposed update to ANSI T1.601 is given together with their motivations. The other standards are only briefly considered. Field experience with ANSI-based maintenance is considered     

Some characteristics of commonly used time scales

Various examples of ideally defined time scales are given. Realizations of these scales occur with the construction and maintanance of various clocks, and in the broadcast dissemination of the scale information. Atomic and universal time scales disseminated via standard frequency and time-signal broadcasts are compared. There is a discussion of some studies of the associated problems suggested by the International Radio Consultative Committee (CCIR).     

Depolarization measurements at 11.6 GHz on Earth-space paths using the SIRIO satellite

Depolarization (XPD) data at 11.6 GHz in circular polarization collected during the SIRIO experiment on the Italian stations of Fucino and Lario are presented and analyzed. The obtained results are presented both in conditional form (i.e., XPD statistics conditioned to the co-polar attenuation (CPA)) and in "equiprobable" form (i.e., by comparing XPD-CPA values exceeded for the same fraction of the total observation time). The conditional XPD appears spread in an interval ofpm5dB around the conditional median value. This latter appears to be very close to the "equiprobable" value. The International Radio Consultative Committee (CCIR) procedure giving the "equiprobable" XPD appears fairly well supported by the Fucino data, while the Lario data give higher depolarization than predicted by CCIR.     

Frequency dependence of rain attenuation measurements at microwave frequencies

The values of attenuation versus frequency for 10 mm/h, 25 mm/h, and 40 mm/h rain rates for frequencies of 11, 18, and 22.2 GHz are presented. On the basis of these observations the attenuation at frequencies below 10 GHz and above 22.2 GHz have been obtained. The values obtained at various frequencies show an agreement with those calculated on the basis of Oguchi's work. Comparison of the above values in dB/km (assuming a path length of 2.5 km) have been made and they show an agreement with International Radio Consultative Committee (CCIR) values. Also cumulative distributions of attenuation at various frequencies have been given taking 11 GHz results as the reference point.     

Reflector sidelobe degradation due to random surface errors

It is well known that the sidelobe structure of a reflector antenna is highly susceptible to random surface errors, and that in most applications it is not adequate to investigate only the average behavior of the antenna. In this study, an attempt is made to determine the probability distribution of the sidelobe level of a reflector antenna subject to some random surface errors. Specifically, the random pattern function is considered and its sidelobe level studied using the level-upcrossing theory. Both the degradation of the maximum sidelobe and the degradation of the sidelobe region with respect to an International Radio Consultative Committee (CCIR) sidelobe envelope are obtained. The theoretical results are found in excellent agreement with those obtained by Monte Carlo simulations. Finally, some useful tolerance charts are presented.