UHF Television Research Articles

Novel Techniques for the Determination of Fluorescence Lifetimes

Abstract: Two novel techniques for the measurement of fluorescence lifetimes are discussed. The first method operates in the frequency domain, selectively amplifying the signals generated by the mode beats of a cw laser with a UHF television tuner. The second approach measures the fluorescence with simultaneous temporal and spectral resolution to simplify the characterization of complex samples.

UHF television interference associated with cellular mobile telephone systems

An investigation is made into two types of interference which may occur between UHF television and 850 MHz cellular mobile telephone systems: 1) ITV--interference to the cellular mobile telephone receivers, created by a UHF TV transmitter; 2) TVI--interference to the UHF TV receiver, created by the cellular system mobile transmitters. In the case of ITV it has been determined that TV transmitters operating on TV channels 65 through 69 may produce third-order intermodulation, within a radius of about 0.5 mi, to certain telephone channels assigned to mobiles operating in a cellular system fringe area. A judicious choice of telephone channel assignments would mitigate this type of degradation. Alternatively, in the case of TVI, it is shown that within a minimum grade B television service area, it is possible for cellular mobile telephones to at times produce image interference to present-day UHF TV receivers tuned to channels 58 through 61. However, because of cellular telephone subscriber density and channel position (and loading) the probability of interference is expected to be low. An increase of TV receiver image rejection by 20 dB would essentially eliminate all likelihood of this interference.

A mobile interference model into UHF television reveivers

A mathematical model to compute the duration of interference into a TV receiver from a land mobile transmitter in the busy hour is proposed. The objective is to determine how various parameters such as mobile density, traffic density, and distance will affect the probability that a transmitting mobile will degrade the picture quality of a TV receiver.

The effect of viewer behavior on reception and viewing of UHF television

The effects of viewer behavior on the reception and viewing of UHF television are explored. By integrating the results from three new studies sponsored by the Federal Communications Commission's UHF Comparability Task Force with previous work it is possible to distinguish between factors that significantly influence UHF viewing and those which do not. The three new studies are: 1) a large public opinion survey by Louis Harris and Associates of 1587 households predicted to receive both UHF and VHF television; 2) measurements of the gain of television receiving systems in 49 households in northern Illinois by the Institute for Telecommunications Sciences (Boulder, CO); and 3) the use of television viewing data collected by The Arbitron Company to study the relationship between UHF television viewing and the type of channel selector. The conclusions reached are: 1) actual UHF reception is significantly poorer than that predicted by the conventional analytical techniques, and the primary cause appears to be inadequate gain in the receiving systems viewers choose to install; 2) actual VHF reception is at least consistent with (if not better than) the conventional predictions; 3) viewers are not biased in their perceptions of UHF reception quality; and 4) the type of channel selector used by a viewer appears to have no impact on the amount of UHF television watched.

UHF television: A review and update

A catalog of improvements to the received signal-to-noise ratio of UHF-television signals is presented, indicating that an overall improvement of 16 dB may be possible. Implementing some or all of the possibilities for improvement could have major benefits to the reception of UHF signals, although the UHF-television industry, appears to be maturing into a successful service in spite of its disadvantages in comparison to VHF television.

UHF television broadcasting in Europe

The development of television broadcasting in Europe is outlined, with particular reference to the circumstances in which operation in the UHF band was introduced. The principles of frequency-assignment planning, together with their application in the case of UHF television, are then described. Attention is drawn to the factors taken into account in the preparation of an internationally agreed frequency-assignment plan for the UHF band, making provision for full national coverage of at least three television program services in each European country. Next follows a description of the present situation, based on a table showing the changes in the principal characteristics of 46 television program services in Western Europe occurring during the period 1970-1980. It is emphasized that UHF operation is now an integral part of the European broadcasting scene, and that in two major countries viewing of UHF transmissions is predominant. After a description of the use of UHF rebroadcast networks as an economical means of extending coverage in mountainous areas, the most likely developments concerning UHF television in Europe during the next few years are reviewed.

IEEE Proceedings Special Issue on UHF Television

IEEE Proceedings Special Issue on UHF Television

The commons In the sky: the radio spectrum and geosynchronous orbit as issues in global policy

Radio waves, which are used to transmit information electronically, are a portion of the larger spectrum of electromagnetic waves. They are used for purposes as diverse as telephone, AM and FM radio, UHF and VHF television, air and marine navigation, radar, radio astronomy, meteorology, data transmission, and electronic mail. Some uses of the spectrum entail transmitting or receiving information via satellites orbiting the planet. In order to communicate without interference at any given time, a user must have exclusive access to a frequency over a geographical area determined by the distance that the signals travel to targeted receivers.

Klystrons for UHF television

The history of television klystrons is described, as are the features of modern television klystrons. Advantages of internal-cavity and external-cavity klystrons are compared. Bandwidth theory and the theory of klystron efficiency, which are matters of particular importance in this application, are also reviewed.

Television Broadcasting at Microwave Frequencies

Over 125 Multipoint Distribution Service (MDS) transmitting stations have been constructed over the past seven years. Each of these stations is equivalent to a low power television broadcast station operating on a microwave frequency at approximately 2,150 MHz. The problems encountered in the design and construction of an MDS station differ markedly from a VHF or UHF television station. The propagation characteristics, likewise, are significantly different than for either UHF or VHF frequencies. The solution to the problem of effective coverage and reception throughout a service area requires innovative designs and techniques, and these are described.

UHF television and the signal strength handicap

The disparate properties of the UHF and VHF bands have produced what has become known as the "UHF handicap" - UHF television (TV) signals are more difficult to receive than VHF signals and therefore are not as significantly viewed. There are at least three possible types of handicaps that contribute to the disadvantage faced by UHF. First, there is the picture quality handicap. Second, there is a channel selector handicap. Finally, there is a programming handicap. In this paper we will be discussing only the picture quality handicap. Furthermore, we will explore only one type of picture quality handicap-the "snow" that is produced by an insufficient signal-to-noise ratio (SNR) at the TV receiver picture tube. Available evidence suggests that this is the dominant difference between UHF and VHF signals. We will utilize a model that indicates the level of this signal strength handicap for several sets of assumptions, and determine the effects of improvements to the UHF service.

The physics of television broadcasting

In order to help the students cope with the design study that formed the basis of the project Scotia competition (see ibid., vol.15, no.4, p.220-2, 1980), the participants were provided with fairly detailed technical information about UHF television broadcasting. The authors summarise this information which should serve as valuable resource material for teachers of physics, electronics and electrical engineering.

The project Scotia competition

In Project Scotia, competing schools had to design a UHF television broadcasting network for the hypothetical Scotia region, supposedly located somewhere on the west coast of Scotland. They then had to prepare a written 'consultants' report' describing and justifying their proposed scheme, and also produce a presentation of the scheme using models, drawings and similar techniques. The project was designed to foster effective interdepartmental and cross disciplinary cooperation. It required the pupils to carry out detailed calculations of a highly technical nature, and also to take full account of all relevant economic, geographical, social and environmental factors.

Bandpass Filter With Dielectric Materials Used for Broadcasting Channel Filter

There are a lot of UHF television translator in Japan, and the equipment itself has been made small by using the recent solid state technology. Our paper reports the miniaturized channel filter with dielectric materials used for UHF television translator equipment in future.

UHF Television Program Performance: Continuing Questions on Spectrum Use

UHF Television Program Performance: Continuing Questions on Spectrum Use

Microwave Integrated Circuit Module for an SHF to UHF Television Converter

The authors have developed an SHF (from 11.7 GHz to 12.2 GHz) to UHF television converter of new circuit structure using a microwave integrated circuit (MIC) module.

Terrestrial SHF Television Broadcasting for VHF and UHF Television Reception Areas Interferred by Buildings

Terrestrial SHF Television Broadcasting for VHF and UHF Television Reception Areas Interferred by Buildings

The Value of Television Time

constraint imposed by the requirement that television stations serve local communities, the Commission has sought, in various ways, to improve the prospects for new stations. The policies pursued or considered have included limitations on the development of cable television as a potential competitor to local broadcasting, the promotion of legislation to require that all television receivers be capable of receiving UHF television, and various attempts to change the frequency allocation plan to reduce the handicap that new stations would face.1 All VHF allocations to commercial tele-

Capability of the FCC mobile monitoring van

The Spectrum Management Task Force of the Federal Communications Commission was formed, in part, for the purpose of devising new methods of spectrum management. Initial efforts have been directed toward improved spectrum utilization in the Land Mobile Service (which includes a large number of different types of users on approximately 2000 channels, assigned on a noncontinuous basis, on three bands (25 to 50 MHz or "low band," 150 to 174 MHz or "high band," and 450 to 470 MHz or "UHF band," with additional channels specifically provided by FCC action in the lower UHF television channels in certain metropolitan areas, and with additional frequency space to become available in the 900-MHz region, but with frequency congestion generally to be found in all large population centers, and apparent maldistribution of users Upon available channels). One technique which is being applied to the overall problem is the mobile spectrum monitoring van designed to measure occupancy, transmission, and other parameters of the land mobile channels.

Global Television — Establishment of an Effective System

The Society's interests in current and future communications by satellites have been manifest on our technical conference programs and in numerous papers in the Journal. — In February 1972 there were, “Television Distribution by the Canadian Domestic Satellite System” by R. M. Lester; “Utilization of Domestic Satellites in the Networks of the CBC” by C. A. Siocos; and “Some Technical Considerations in Providing Television Coverage by Satellite” by J. F. D. Ball. The March 1972 Journal contained “Broadcasting From Satellites” by C. A. Siocos; “Broadcasting From Satellites — UHF Television Channel Utilization” by R. F. Zeitoun and C. A. Siocos; “Possible Technical Standards for Educational and Community Television by Satellite” by R. P. Haviland; and “Combined Educational and Television Network Satellite Distribution System” by Daniel R. Wells. In December 1972 there was “Apollo 15 and 16 Ground-Commanded Television Assembly” by Bert M. Soltoff. — In October 1972 a series of papers and discussions was held in Los Angeles as the Symposium on Communication Satellites and Cable Television; those papers will soon be published in the Journal. — In addition to the conventional applications related to commercial broadcasting other interesting possibilities are being investigated. Two experimental satellites, one by the U.S.A., the other Canadian, will be launched in 1974 and 1975, respectively, for experimental communication programs. New advances in traveling wave lube design are expected to simplify ground station design, lessen the size and increase mobility. We are privileged to present here, in slightly abridged form, a recent speech given by Robert W. Sarnoff on this subject. In it, he outlines some of the broad possibilities, difficulties and concerns for the future as we advance towards more simplified and efficient means of providing worldwide communication links.—Gerald G. Graham, Editorial Vice-President