BBC Research and Development Reports
A collection of BBC Research and Development reports and white papers, dating from the 1960s through to 1996.
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R&D Report 1994-12 : A wideband absorber for television studios. M.D.M. Baird The acoustic treatment in BBC television studios has taken various forms to date, all of which have been relatively expensive, some of which provide inadequate absorption. An investigation has been conducted into the possibilities of producing a new type of wideband absorber which, would be more economic, also taking installation time into account, than earlier designs. This Report describes the absorption...
Topics: absorption, absorber, wideband, frequency, acoustic, mineral, bbc, zintec, weldmesh, absorbers,...
Topics: absorption, absorber, wideband, frequency, acoustic, mineral, bbc, zintec, weldmesh, absorbers,...
R&D Report 1963-03 : Visit to United States - 30th November to 9th December 1962. H. Page, D.E. Todd The BBC were invited to send representatives to a Conference of the VOA Science Advisory Group which was held at Greenville North Carolina from December 3rd - 5th 1962. This is a report of that visit.
Topics: rca, voa, colour, transmitters, fcc, sideband, bbc, propagation, srl, transmitter, colour camera,...
Topics: rca, voa, colour, transmitters, fcc, sideband, bbc, propagation, srl, transmitter, colour camera,...
R&D Report 1964-24 : Service areas of the Great Glen chain of television and VHF sound transmitters. R.C. Vercoe, H.T. Madoc-Jones, J.A. Carter The results of field strength surveys of the Great Glen Chain of television and v.h.f sound transmitter are given in this report.
Topics: transmitters, exceeded, kinlochleven, aerial, television, ballachulish, receiving, fort, strength,...
Topics: transmitters, exceeded, kinlochleven, aerial, television, ballachulish, receiving, fort, strength,...
R&D Report 1964-78 : Transmitting aerials for the Hereford VHF television and VHF sound station D.W. Osborne A brief summary of the installation of Hereford Relay Station.
Topics: aerials, transmitting, horizontal, band, templet, gain, hereford, aerial, radiation, receiving,...
Topics: aerials, transmitting, horizontal, band, templet, gain, hereford, aerial, radiation, receiving,...
BBC Research and Development Reports
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R.D. Pittilo, S.J. Ashdown, J. Hall
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R&D Report 1954-18 : Channel Islands television site test. R.D. Pittilo, S.J. Ashdown, J. Hall Tests have been made from a site at Les Platons on the north coast of Jersey. It was found that a transmitter sited here would serve both Jersey and Guernsey adequately.
Topics: strength, guernsey, field, transmitter, contours, islands, jersey, channel, les, site, islands...
Topics: strength, guernsey, field, transmitter, contours, islands, jersey, channel, les, site, islands...
R&D Report 1980-08 : Revised background noise criteria for broadcasting studios. D.J. Meares, K.F.L. Lansdowne To achieve the correct working conditions in its studios, the BBC has, for many years, specified the maximum level of background noise that can be tolerated. This Report examines the 1968 noise criteria bearing in mind the performance of the current broadcasting network, and concludes that revisions are necessary. Based on a study of estimated and measured signal-to-acoustic noise...
Topics: noise, studio, studios, acoustic, criteria, sound, ventilation, bbc, criterion, drama, noise level,...
Topics: noise, studio, studios, acoustic, criteria, sound, ventilation, bbc, criterion, drama, noise level,...
R&D Report 1966-45 : UHF service area prediction: an investigation using relief map photography E. Sofaer, R. Sims An experiment was undertaken to determine whether the service areas of u.h.f. broadcasting transmitters could be reliably predicted by photographing a three-dimensional relief map suitably illuminated. The results obtained are discussed.
Topics: predicted, map, ccir, contour, lamp, errors, field, prediction, service area, measured, service...
Topics: predicted, map, ccir, contour, lamp, errors, field, prediction, service area, measured, service...
R&D Report 1980-07 : Crystal Palace Band II tests: comparison of transmitted polarizations. J.H. Causebrook A description is given of an experiment conducted in the London area, with a test transmitter at Crystal Palace, to examine the relative merits of different polarizations for Band II FM radio broadcasts. The tests allowed for reception at roof-top level, in cars, and on portables. The relative amounts of multipath were assessed. It is concluded that in heavily built up areas, as well...
Topics: vertical, aerial, reception, horizontal, receiving, aerials, transmitter, polarization, field,...
Topics: vertical, aerial, reception, horizontal, receiving, aerials, transmitter, polarization, field,...
R&D Report 1966-32 : Sennheiser MKH 404 and AKG 628 microphones. H.D. Harwood Two new capacitor microphones, the Sennheiser type MKH 404 and the Akustische und Kino Gerate type 628, have been produced which employ transistor circuits and radio-frequency polarizing of the capsule; both have a cardioid directional characteristic and are of the end-fire type. Measurements of the frequency characteristics have been carried out for sound incident at various angles; the degree of self-generated...
Topics: mkh, type, sennheiser, akg, impedance, frequency, noise, microphone, microphones, circuit, akg...
Topics: mkh, type, sennheiser, akg, impedance, frequency, noise, microphone, microphones, circuit, akg...
R&D Report 1964-17 : Transmitting aerial for the Holyhead VHF television station D.W. Osborne A brief summary of installation of Holyhead relay station.
Topics: aerial, transmitting, horizontal, tower, height, technological, channel, holyhead, dipoles, dipole,...
Topics: aerial, transmitting, horizontal, tower, height, technological, channel, holyhead, dipoles, dipole,...
R&D Report 1975-24 : Prototype equipment to measure co-channel interference on 625-line television signals. M.J. Kallaway This report describes prototype equipment designed to measure the level of co-channel interference (CCI) on a 625-line television signal. The CCI measuring equipment's primary application is at transmitters fed by re-broadcast links (RBL) where it would measure the level of CCI on the incoming television signal and record it on a chart recorder. The CCI measuring...
Topics: offset, frequency, equipment, level, interference, nominal, filter, measuring, interfering, pulses,...
Topics: offset, frequency, equipment, level, interference, nominal, filter, measuring, interfering, pulses,...
R&D Report 1972-07 : The optimum characteristics for a simple luminance notch in a PAL colour television decoder S.J. Lent The various considerations which govern the characteristics of a luminance notch filter in a PAL decoder are discussed and subjective experiments are described which were carried out to find the optimum characteristics of such a filter.
Topics: notch, luminance, chrominance, characteristics, notches, pal, optimum, subcarrier, sidebands,...
Topics: notch, luminance, chrominance, characteristics, notches, pal, optimum, subcarrier, sidebands,...
R&D Report 1977-39 : Direct satellite broadcasing: intermodulation between multiple FM sound subcarriers. M.J. Kallaway The report describes an experimental study of the effects of intermodulation between multiple fm sound subcarriers. Such a system could provide supplementary sound channels for satellite broadcasting, where the subcarriers would frequency-modulate a 12 GHz carrier. The report concludes that a system using twelve fm sound subcarriers is very sensitive to intermodulation. To...
Topics: subcarrier, subcarriers, mhz, deviation, signal, carrier, intermodulation, frequency, amplitude,...
Topics: subcarrier, subcarriers, mhz, deviation, signal, carrier, intermodulation, frequency, amplitude,...
R&D Report 1981-02 : An investigation into the spectral content of pop music. K.E. Randall In the design of a high-level studio monitoring loudspeaker, account must be taken of the type of programme that will be fed to it. When used to monitor pop music, which may contain relatively high levels of low frequencies, the maximum sound pressure level obtainable may be restricted by cone-movement limitations to a value which is unacceptably low for the studio manager to obtain the correct music...
Topics: loudspeaker, pop, music, spectra, sound, signal, levels, bbc, spectral, extract, octave band,...
Topics: loudspeaker, pop, music, spectra, sound, signal, levels, bbc, spectral, extract, octave band,...
BBC Research and Development Reports
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J.T. Zubrzycki
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R&D Report 1996-12 : Mobile Broadband System. A report on the work of RACE Project 2067. J.T. Zubrzycki Mobile Broadband System (MBS) is a wireless cellular radio network capable of carrying digital signals at bit rates sufficient for digital video, including compressed HDTV. The technological feasibility has been studied in RACE* Project 2067 MBS, which had the aim to extend the Broadband Integrated Services Digital Network (B-ISDN) to mobile users, providing much higher capacity to users...
Topics: mbs, mobile, ghz, base, broadband, demonstrator, antennas, antenna, project, diversity, diversity...
Topics: mbs, mobile, ghz, base, broadband, demonstrator, antennas, antenna, project, diversity, diversity...
R&D Report 1967-13 : The dynamic characteristics of limiters for sound programme circuits D.E.L. Shorter, W.I. Manson, D.W. Stebbings Subjective tests have been carried out to establish the optimum dynamic characteristics of limiters used to protect transmitters and other equipment in the sound programme chain against overload through excessive signal levels. It was found impossible, with existing types of limiter, to avoid momentary excessive signal levels at the output unless the gain...
Topics: limiter, signal, gain, overshoot, recovery, delay, control, distortion, output, circuit, gain...
Topics: limiter, signal, gain, overshoot, recovery, delay, control, distortion, output, circuit, gain...
BBC Research and Development Reports
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P. Knight, G.D. Monteath, G.J. Phillips
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R&D Report 1955-33 : Vertically polarised Band III aerial for Crystal Palace. P. Knight, G.D. Monteath, G.J. Phillips This report describes the first stage in the development, using a small-scale model, of a vertically-polarised aerial for radiating two television programmes in Band III from the Crystal Palace television station. The aerial consists of 8 tiers of tangential batwing elements mounted on a 4 ft 4 in. (1.32 m) square section of the tower.
Topics: admittance, aerial, elements, iii, tiers, mast, feeder, batwing, tier, element, mutual admittance,...
Topics: admittance, aerial, elements, iii, tiers, mast, feeder, batwing, tier, element, mutual admittance,...
R&D Report 1962-38 : The Fernseh standards converter: Visit to Rome and Darmstadt 16th - 19th July 1962. P. Ranger, E.R. Rout The report gives an overview of the visit to Rome and Darmstadt in July 1962 by members of the department to discuss, The Fernesh Standards Converter.
Topics: converter, flicker, vidicon, conversion, display, lag, standards, fernseh, portrayal, camera, scale...
Topics: converter, flicker, vidicon, conversion, display, lag, standards, fernseh, portrayal, camera, scale...
R&D Report 1970-21 : The design and replacement aerials for Moorside Edge P. Knight The design of a new medium-frequency aerial system for Moorside Edge is described. The effect of the hilly nature of the surrounding area on the performance of the aerials is discussed, and it is concluded that no advantage could be gained by centre-feeding.
Topics: aerial, mast, moorside, wires, radio, radiation, aerials, height, radius, antifading, height...
Topics: aerial, mast, moorside, wires, radio, radiation, aerials, height, radius, antifading, height...
R&D Report 1966-55 : Differential fading of television signals at UHF C.P. Bell When receiving television signals at a translator rely station, for re-transmission after frequency changing, a common amplifier for sound and vision signals is usually employed. Thus the power ratio of the re-transmitted signals is the same as that received from the parent station. Differential fading of the sound and vision signals is therefore important, inasmuch as it would affect this radio. This report...
Topics: fading, vision, receiving, differential, measurements, caversham, sound, aerial, height,...
Topics: fading, vision, receiving, differential, measurements, caversham, sound, aerial, height,...
BBC Research and Development Reports
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G.D. Monteath
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R&D Report 1954-11 : The specification of the reflection coefficient of a F.M. aerial. G.D. Monteath If an aerial radiating f.m. transmissions is not matched to its feeder, amplitude modulation is introduced and the a.f. signal suffers non-linear distortion. The distortion is most marked if the receiver lacks a limiter. These effects are examined in this report and a limit for the reflection coefficient at the aerials is proposed. This constitutes a considerable relaxation of the...
Topics: amplitude, distortion, feeder, reflection, receiver, instantaneous, harmonic, frequency, maximum,...
Topics: amplitude, distortion, feeder, reflection, receiver, instantaneous, harmonic, frequency, maximum,...
R&D Report 1962-10: V.H.F. sound broadcasting: Mutual interference between transmissions with 100 kc/s channel separation radiating either the same or different programmes. J.G. Spencer Subjective tests have been carried out, using four recent models of domestic a.m./f.m. sound receivers, to determine to permissible ratio of wanted- to unwanted-carrier levels when an interfering f.m. transmission is spaced by 100 kc/s from a wanted f.m. transmission and is broadcasting either the same or a...
Topics: interference, signal, ratio, programme, frequency, transmission, receiver, interfering, modulation,...
Topics: interference, signal, ratio, programme, frequency, transmission, receiver, interfering, modulation,...
R&D Report 1963-18 : Visibility of small luminance perturbations in television displays. G.F. Newell, W.K.E. Geddes Measurements of the visibility of small-magnitude luminance perturbations at various parts of the grey scale have been carried out using television displays. (This report includes, in a revised and condensed form, material already published in Research Department Reports T-083 and T-092, as well as the results of further work carried out since these reports were written). The...
Topics: luminance, visibility, noise, random, displayed, pattern, test, signal, experiments, perturbing,...
Topics: luminance, visibility, noise, random, displayed, pattern, test, signal, experiments, perturbing,...
R&D Report 1965-08 : Specification of the impedance of transmitting aerials for monochrome and colour television signals D.J. Whythe Any departure of the impedance of a television transmitting aerial from the characteristic impedance of its feeder results in the transmission of delayed signals. This report specifies the maximum departures of impedance that are permissible without visible distortion for 405-line and 625-line monochrome and colour television signals. The specifications for...
Topics: delayed, signal, aerial, impedance, feeder, signals, reflexions, monochrome, transmitter,...
Topics: delayed, signal, aerial, impedance, feeder, signals, reflexions, monochrome, transmitter,...
R&D Report 1964-27 : Visit to Telefis Eireann, 5th and 6th March 1964 E.R. Rout Members of BBC Research visited Telefis Eireann in March 1964, the following report is an account of that visit.
Topics: telefis, eireann, converter, receivers, studio, eire, bbc, transmissions, vidicon, transmitters,...
Topics: telefis, eireann, converter, receivers, studio, eire, bbc, transmissions, vidicon, transmitters,...
R&D Report 1963-32 : Transmitting aerials for the Oban television and VHF sound station. D.W. Osborne A brief summary of the installation.
Topics: aerial, gain, oban, aerials, horizontal, tower, templet, band, spacing, sound, sound station,...
Topics: aerial, gain, oban, aerials, horizontal, tower, templet, band, spacing, sound, sound station,...
R&D Report 1963-36 : Varotal V. A 10 to 1 zoom lens for the image orthicon format (No 617566) W.N. Sproson Measurements are reported on the zoom lens Varotal V. These include modulation transfer factor, vignetting, transmission and veiling glare and geometrical distortion. An overall assessment based on sharpness and vignetting is given and comparisons are made with other lenses, both of fixed focal-length and of varifocal length.
Topics: focal, aperture, lens, modulation, lenses, length, zoom, varotal, curves, transfer, geometrical...
Topics: focal, aperture, lens, modulation, lenses, length, zoom, varotal, curves, transfer, geometrical...
R&D Report 1968-46 : Calculation of the field strength required for a television service, in the presence of co-channel interfering signals. Part 3: The computer program R.W. Lee Parts 1 and 2, which have been issued separately, give the theory underlying the calculation processes which have been actually used in the BBC Research Department. Part 3 describes the original computer program used for carrying them out.
Topics: transmitter, field, terrain, location, test, interfering, calculation, strength, path, calculate,...
Topics: transmitter, field, terrain, location, test, interfering, calculation, strength, path, calculate,...
R&D Report 1968-15 : Kingussie VHF relay station: Summary of installation R.D.C. Thoday, J.P. Crean Brief data sheet detailing equipment used, frequencies, radiation characteristics etc, together with graphs of horizontal and vertical radiation patterns.
Topics: aerial, band, transmitting, aerials, pole, horizontal, receiving, etn, tier, installation,...
Topics: aerial, band, transmitting, aerials, pole, horizontal, receiving, etn, tier, installation,...
R&D Report 1973-38 : Holography: A general survey E.W. Taylor The history of the development of holography is surveyed and an introduction to the general theory is given. Techniques for the preparation of holograms are described, and materials for use as holographic recording media are discussed. An extensive list of references is included.
Topics: holographic, hologram, beam, interference, image, photographic, radiation, object, light,...
Topics: holographic, hologram, beam, interference, image, photographic, radiation, object, light,...
R&D Report 1973-32 : Solid state sensors: The use of a single dimension 512 element array for film scanning D.T. Wright Following some early experiments with a 72 element self-scanned linear array of photo-diodes, a 512 element array was obtained. This has been used to scan continuously moving film since this provides a convenient means of assessing the potential of single dimension solid state image pick up devices. The method of application and the resulting performance are discussed.
Topics: array, output, film, signal, mhz, scanning, scanned, clock, lens, saturation, stored correction,...
Topics: array, output, film, signal, mhz, scanning, scanned, clock, lens, saturation, stored correction,...
R&D Report 1978-22 : Narrow-band FM system for television links: tests of performance under conditions of multipath propagation. N.H.C. Gilchrist Mobile transmitters have a number of uses in television outside broadcasts; examples are found in the coverage of horse-racing, where a television camera mounted on a moving road vehicle provides close-up pictures of competitors, and also at golf tournaments and boat-races, where helicopters have been used to carry cameras. Multi-path propagation...
Topics: receiver, multipath, threshold, roving, signal, balloons, system, synchronism, limiter, videotape,...
Topics: receiver, multipath, threshold, roving, signal, balloons, system, synchronism, limiter, videotape,...
R&D Report 1993-12 : Predicted coverage of a COFDM Single Frequency Network for UHF digital terrestrial TV broadcasting M.B.R. Lee The Coded Orthogonal Frequency Division Multiplex (COFDM) transmission system provides a very high degree of tolerance towards multipath interference. Three factors contribute towards this tolerance; the inclusion of a guard interval, coding to provide error correction and the division of the digital data amongst a very large number of low bit rate carriers. It...
Topics: coverage, antenna, guard, digital, field, directional, interval, transmitters, bbc,...
Topics: coverage, antenna, guard, digital, field, directional, interval, transmitters, bbc,...
R&D Report 1961-12 : AKG electrostatic microphones Types C26 and C28. H.D. Harwood, J.R. Chew, R.L. Deane, R.J. Packer This report describes tests on two electrostatic microphones manufactured by the Akustische und Kino-Gerate Gesellschaft (A.K.G.). The first, type C26, has omnidirectional and the second, type C28, cardioid characteristics. The microphones are of small dimensions and provision is made in each case for introducing an extension piece between the capsule and the head...
Topics: type, microphone, capsule, extension, interference, impedance, characteristics, frequency, noise,...
Topics: type, microphone, capsule, extension, interference, impedance, characteristics, frequency, noise,...
R&D Report 1968-06 : Experimental equipment for converting television signals into digital signals and vice versa V.G. Devereux, M.T.A. Salter The report describes equipment which has been constructed for converting a television signal into digital form and reconverting to conventional form. The television signal is sampled at a rate of 13 million samples/sec and a 6-bit digital signal is derived which indicates the magnitude of each sample as one of 64 binary numbers. It was found that...
Topics: signal, digital, pulses, video, sample, unit, quantized, signals, output, converter, weighting...
Topics: signal, digital, pulses, video, sample, unit, quantized, signals, output, converter, weighting...
R&D Report 1994-04 : Multi-channel sound for HDTV: Subjective tests on sound channel configuration J.A. Fletcher This report describes subjective tests carried out as part of the Eureka 95 project to compare different multi-channel sound systems being considered for use with HDTV. In the tests, the number of sound channels varied from one (mono) to five (three front channels and two surround channels). The improvement in quality obtained by increasing the number of front channels from two...
Topics: zirkus, knie, preference, surround, acrobats, vilia, tipsy, listeners, sound, eliott, knie peg,...
Topics: zirkus, knie, preference, surround, acrobats, vilia, tipsy, listeners, sound, eliott, knie peg,...
BBC Research and Development Reports
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B. Davis, G.D. Monteath, G.I. Ross
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R&D Report 1956-34 : Investigation of poor reception from Crystal Palace in the Reigate and Horsham areas B. Davis, G.D. Monteath, G.I. Ross An investigation has been made into complaints of poor reception, in the Reigate, Redhill and Crawley and Horsham districts, of the Crystal Palace television transmitter installation, in its temporary conditions. The field strength in these areas is lower than the value predicted from site test measurements and the prevalence of flutter fading due to...
Topics: palace, crystal, strength, field, tower, alexandra, flutter, horsham, measurements, aircraft, site...
Topics: palace, crystal, strength, field, tower, alexandra, flutter, horsham, measurements, aircraft, site...
R&D Report 1963-13 : Optical line broadening. W.N. Sproson, C.J. Dalton The line structure associated with a television picture is regarded by most observers as somewhat undesirable and several proposals have been made for the reduction or complete elimination of the line structure. These have been described in some detail in a recent report. The purpose of the present note is to describe some experiments on one of the optical proposed in the above-mentioned report.
Topics: spatial, lens, frequency, response, tangential, image, sagittal, focus, field, optical, small...
Topics: spatial, lens, frequency, response, tangential, image, sagittal, focus, field, optical, small...
R&D Report 1960-16 : Band II receiving aerial for a motor car H. Page, J.A.S. Fox Although the very-high-frequency (vhf) sound service in Band II (87.5 - 95 Mc/S) now provides virtually complete coverage of the United Kingdom, the car receivers in use in this country rarely incorporate a vhf range. This is probably because the medium-frequency (mf) transmitters give reasonably satisfactory reception in a car of all British programmes. The main drawbacks are fading, man-made interference,...
Topics: aerial, horizontal, radiation, ratio, band, height, whip, sensitivity, receiving aerial, reference,...
Topics: aerial, horizontal, radiation, ratio, band, height, whip, sensitivity, receiving aerial, reference,...
R&D Report 1966-30 : Visibility of sound/chrominance pattern with the PAL system: Dependence upon offset of intercarrier frequency and upon sound modulation. R.V. Harvey In order to minimize the visibility of the sound/chrominance beat pattern in compatible reception of PAL colour transmissions, an optimum sound/vision intercarrier frequency may be specified, together with a frequency tolerance. For the U.K. Standard I the results of subjective assessments of the pattern show than an...
Topics: pattern, frequency, visibility, carrier, sound, pal, subcarrier, offset, mhz, intercarrier, colour...
Topics: pattern, frequency, visibility, carrier, sound, pal, subcarrier, offset, mhz, intercarrier, colour...
R&D Report 1963-42 : Bush transistor AM/FM portable receiver Model VTR 103 P.J.E. Harvey This report gives the results of tests on the Bush VTR 103 on the VHF FM range. The general performance is good. The quality of reproduction is pleasing and output volume is adequate.
Topics: frequency, receiver, signal, ratio, deviation, sensitivity, input, output, harmonic, distortion,...
Topics: frequency, receiver, signal, ratio, deviation, sensitivity, input, output, harmonic, distortion,...
R&D Report 1975-05 : Determination of the phase-centre of a UHF ruggedised log-periodic aerial in the H-plane . J.L. Riley The phase-centre concept as applied to a log-periodic aerial is discussed. The radiation pattern phase of a UHF ruggedised log-periodic aerial is used to establish its 'apparent' phase-centre in the H-plane.
Topics: aerial, phase, radiation, ruggedised, bbc, method, amplitude, pattern, voltmeter, measurement,...
Topics: aerial, phase, radiation, ruggedised, bbc, method, amplitude, pattern, voltmeter, measurement,...
R&D Report 1978-08 : Channel Islands link for BBC television programmes: the Alderney receiving installation. G.H. Millard Colour television programmes for the Channel Islands are obtained from the mainland by direct reception of UHF transmissions on a long oversea path. The consequent variability and distortion of the signal has demanded special features of the receiving installation which are described in this report.
Topics: aerial, channel, bbc, interference, array, alderney, signal, aerials, parabolic, diversity, aerial...
Topics: aerial, channel, bbc, interference, array, alderney, signal, aerials, parabolic, diversity, aerial...
R&D Report 1994-14 : The sound insulations of studio doors: Part 1: Door Blanks G.D. Plumb, R. Clark The sound insulations of a range of different door blanks were measured. The results were compared with the sound insulations of existing BBC door blanks. The new doors were made from medium density fibreboard (MDF) which is more stable than the blockboard used in existing studio doors. Consequently, they should require less maintenance and adjustment and should have a longer lifespan. The...
Topics: mdf, door, insulations, bitumen, damping, measured, bbc, sound, acoustic, lightweight, band centre,...
Topics: mdf, door, insulations, bitumen, damping, measured, bbc, sound, acoustic, lightweight, band centre,...
R&D Report 1994-07 : Further measurements of the sound insulations of metal-framed partitions. G.D. Plumb The sound insulations were measured of a number of single and double leaf metal-framed partitions. The purpose of the work was to develop alternative designs for partitions to that of the Camden. The Camden contains fibreboard as one of its constituent elements. The new partitions used plasterboard as the sole board material. Therefore, the new partitions were heavier than the...
Topics: partition, partitions, insulations, plasterboard, wool, narrow, leaf, sound, camden, insulation,...
Topics: partition, partitions, insulations, plasterboard, wool, narrow, leaf, sound, camden, insulation,...
R&D Report 1968-37 : Aspects of frequency-division-multiplex colour systems for television field-store standards converters D.W. Osborne This report describes an investigation into certain aspects of a proposal to use a frequency-division-multiplex system for the transmission of a colour television signal through the 'advanced' Field-Store Standards Converter. The investigation showed that the use of such a system, within the band-width of currently-available ultrasonic delay, would be...
Topics: intermodulation, order, signal, luminance, interference, unit, delay, frequencies, signals,...
Topics: intermodulation, order, signal, luminance, interference, unit, delay, frequencies, signals,...
R&D Report 1964-35 : Service areas of the Holme Moss television and VHF sound transmitters J.H. Causebrook, J.A. Carter A brief summary of the installation of Holme Moss Relay Station
Topics: field, vision, sound, strength, medi, median, holme, transmitters, town, moss, moss television,...
Topics: field, vision, sound, strength, medi, median, holme, transmitters, town, moss, moss television,...
R&D Report 1960-17 : Sound insulation and acoustics of the new studios in the Centre Block, Bush House. C.L.S. Gilford This report describes the design, with respect to acoustics and sound insulation, of the studios recently built in the Centre Block of Bush House. The principles of design are not new but in this application there was considerable compromise on grounds of cost and appearance. The first section, dealing with sound insulation, describes how the design was started from a new...
Topics: studios, studio, insulation, reverberation, absorption, transmission, cubicle, sound, cubicles,...
Topics: studios, studio, insulation, reverberation, absorption, transmission, cubicle, sound, cubicles,...
R&D Report 1963-17 : Method for estimating the protection requred by a television service against interference from several sources. E. Sofaer An engineer planning a television service in a channel already occupied by other transmissions must be able to estimate the combined effect of interference from several sources Severity of interference is judged subjectively, and an ideal method of making the estimate would be one which gave the answer directly in terms of a subjective judgement....
Topics: probability, deviation, logarithmic, location, interference, variations, tion, standard, field,...
Topics: probability, deviation, logarithmic, location, interference, variations, tion, standard, field,...
R&D Report 1995-05 : Controlled Image Designs: Results from the first installations R. Walker Following successful evaluation of the experimental installation, the principle was used in the BBC as the basis for the design of three refurbished control rooms in Broadcasting House, London and one new control room for the Transcription Service in Bush House. The results of acoustic tests from these areas are presented. The problems of reflections from the top surfaces of mixing desks are also...
Topics: loudspeaker, response, reflections, frequency, msec, design, reflection, acoustic, cubicle,...
Topics: loudspeaker, response, reflections, frequency, msec, design, reflection, acoustic, cubicle,...
R&D Report 1981-10 : Digital audio: recursive digital filtering for high quality audio signals. G.W. McNally A high speed, low cost digital signal processor has been designed and built suitable for real-time operations on high quality sound signals. The purpose of the work described in this Report is to examine its application to audio filters of a kind currently found in equipment such as mixing desks. The methods by which digital audio filters may be designed are reviewed and a detailed...
Topics: filter, digital, filters, structure, noise, coefficients, roundoff, structures, output, signal,...
Topics: filter, digital, filters, structure, noise, coefficients, roundoff, structures, output, signal,...
R&D Report 1966-31 : Colour film and colour television C.B.B. Wood This report discusses the use of colour film for colour television, with particular reference to the choice of film stocks.
Topics: colour, film, television, mhz, eastman, kodachrome, telerecording, films, ektachrome, contrast,...
Topics: colour, film, television, mhz, eastman, kodachrome, telerecording, films, ektachrome, contrast,...
BBC Research and Development Reports
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A.E. Axon, A. Stott
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R&D Report 1954-26 : The subjective discrimination of pitch and amplitude fluctuations in recording systems A.E. Axon, A. Stott. The present report is largely concerned with the subjective aspects of wow and flutter and describes work carried out to determine the sensitivity of the listener to these pitch fluctuations.
Topics: modulation, frequency, amplitude, flutter, frequencies, subjective, fluctuations, threshold,...
Topics: modulation, frequency, amplitude, flutter, frequencies, subjective, fluctuations, threshold,...
BBC Research and Development Reports
by
J.G. Spencer
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R&D Report 1959-02 : A transportable Band II F.M. receiver for studying multiple propagation paths. J.G. Spencer This report describes a transportable Band II f.m. receiver which provides both an audio-frequency output to an internal or external loudspeaker, and a visual display of the amplitude/frequency characteristic of the propagation path of the received signal. It was designed to assist in the investigation of the incidence and effects of multipath propagation in f.m. broadcasting.
Topics: oscilloscope, receiver, frequency, propagation, deflection, modulation, display, amplitude, signal,...
Topics: oscilloscope, receiver, frequency, propagation, deflection, modulation, display, amplitude, signal,...
R&D Report 1960-18 : An experimental transistor receiver for VHF sound broadcast reception. R.V. Harvey The report describes the design of an experimental transistor f.m. broadcast receiver. The circuit uses ten transistors which are currently available at moderate cost, and embodies a recently developed type of limiter and discriminator. The performance is equal, in the more important respects, to that of the better quality domestic receiver using valves.
Topics: output, receiver, oscillator, limiter, suppression, discriminator, frequency, signal, transistor,...
Topics: output, receiver, oscillator, limiter, suppression, discriminator, frequency, signal, transistor,...
R&D Report 1962-26 : Pattern visibility in television co-channel interference. E.W. Taylor The dependence of the subjective visibility of the primary interference pattern upon offset and protection ratio is discussed. On the assumption that the inclination of the interference stripes does not affect the visibility of the pattern, it is suggested that offsets may be gathered into a number of groups, each group containing offsets giving rise to patterns of equal visibility. The relationship...
Topics: offset, pattern, offsets, interference, ratio, visibility, frequency, stripes, curve, curves, wide...
Topics: offset, pattern, offsets, interference, ratio, visibility, frequency, stripes, curve, curves, wide...
R&D Report 1964-63 : Time variations of UHF and VHF signals at short distances J.W. Stark Field strength measurements of transmissions from Crystal Palace in Channels 1, 34 and 44 were carried out at distance of 11 miles (17.7. km) and 31.7. miles (51.0 km). The results show that the Channel 44 median signals are 3 to 4 dB lower in summer than in winter, presumably due to absorption by foliage. There is no corresponding effect on Channel 1 signal levels. During abnormal propagation...
Topics: baddow, kingswood, channel, field, transmitting, measurements, fading, median, receiving, great,...
Topics: baddow, kingswood, channel, field, transmitting, measurements, fading, median, receiving, great,...
R&D Report 1969-37 : Harmonic radiation from UHF television transmitting stations D.J. Whythe, N.H.C. Gilchrist This report describes measurements of the levels of second and third harmonic signals at Crystal Palace (Channel 33) and of second harmonic signals at Emley Moor Channel 51), both in the feeders and radiated from the aerial. The radiated levels were so low that they could be measured only within very close range from the transmitter. The general harmonic level in the feeders was...
Topics: harmonic, feeders, levels, radiated, crystal, transmitter, aerial, emley, level, measured, jodrell...
Topics: harmonic, feeders, levels, radiated, crystal, transmitter, aerial, emley, level, measured, jodrell...
R&D Report 1969-09 : The susceptibility of portable band II FM receivers to interference by services operating in adjacent frequency bands C.R.G. Reed Nine portable receivers, designed for FM reception and retailing at prices ranging from under 10 to over 25 pounds, were tested for their susceptibility to interference by an amplitude-modulated signal whose carrier frequency differs from that of the wanted signal by between 300 kHz and 3.5 MHz. The tests were repeated on some of the...
Topics: signal, interfering, receiver, receivers, frequency, tests, modulation, interference, deviation,...
Topics: signal, interfering, receiver, receivers, frequency, tests, modulation, interference, deviation,...
R&D Report 1974-19 : Digital sound: Feasibility of changing frequency pre-emphasis by a digital filter T.A. Moore This report investigates the feasibility of using a digital filter to change the pre-emphasis applied to an audio signal encoded in digital form from the CCIR (50 microseconds) characteristic to the CCITT characteristic. This filter is required at the interface between bit-streams carrying 13-bit and companded 10-bit digital sound signals. The disadvantage of using an analogue...
Topics: filter, digital, analogue, quantising, response, signal, truncation, frequency, khz, output, input...
Topics: filter, digital, analogue, quantising, response, signal, truncation, frequency, khz, output, input...
R&D Report 1973-09 : Hybrid-pulse coding: An experimental quadrature modulation system for television transmission R.V. Harvey A comparison of PCM and hybrid PCM is given and experimental tests on a particular HPCM system are described. The limitations and difficulties of a system using HPCM, both fundamental and instrumental, are discussed. It is concluded that, while the efficiency offered by a HPCM transmission system can approach the theoretical limit, this demands a high order of...
Topics: signal, analogue, quadrature, bandwidth, bbc, modulation, threshold, system, ratio, experimental,...
Topics: signal, analogue, quadrature, bandwidth, bbc, modulation, threshold, system, ratio, experimental,...
R&D Report 1979-19 : Ground-wave propagation in a realistic terrain. J.H. Causebrook, B. Tait LF and MF ground-wave propagation over a realistic terrain has been found to be very different to that over an assumed smooth earth. This report describes the basic nature of these differences, which include a non-simple relationship for field variation with distance and a non-free-space relationship between magnetic and electric fields. The theory of why these effects occur is summarized, and the...
Topics: field, khz, magnetic, electric, terrain, clutter, transmitter, measurements, bbc, impedance, free...
Topics: field, khz, magnetic, electric, terrain, clutter, transmitter, measurements, bbc, impedance, free...
R&D Report 1977-44 : Traffic information service: trials and developments 1975/76. M.W. Harman The report forms a continuation of earlier work which established the need and feasibility of introducing a dedicated traffic information service, using a single medium frequency in time division multiplex, to serve the United Kingdom. A study of the effectiveness of a muting system in the receiver relying entirely on signal strength for restricting the coverage of each transmitter to local areas,...
Topics: brookmans, receiver, mute, field, transmitter, tatsfield, traffic, khz, efficiency, strength,...
Topics: brookmans, receiver, mute, field, transmitter, tatsfield, traffic, khz, efficiency, strength,...
R&D Report 1976-35 : Some considerations on the use of pre-amplifiers at low-power UHF relay stations. J.L. Riley A number of inexpensive, commercially available pre-amplifiers are examined and their performances in respect of gain, noise factor, linearity and impedance match are compared. Some theoretical planning curves are presented for considering low-field conditions and formulae are derived for dealing with high-signal conditions. A re-broadcast link front-end, made up from the most...
Topics: amplifier, input, aerial, output, isolation, amplifiers, signal, noise, receiving, feeder, received...
Topics: amplifier, input, aerial, output, isolation, amplifiers, signal, noise, receiving, feeder, received...
R&D Report 1983-10 : The design of the prototype LS5/9 studio monitoring loudspeaker. K.E. Randall, C.D. Mathers The prototype of a new medium-power studio monitor is described which is physically small enough to be accommodated in areas where a large high-power monitor would be inappropriate. The main design and performance features are as follows:- A vented cabinet having a volume of 28 litres (1 cubic foot). Two drive units; a proprietary 34mm soft-domed high-frequency unit and a BBC...
Topics: loudspeaker, unit, frequency, sound, diaphragm, drive, bbc, profile, crossover, prototype, sound...
Topics: loudspeaker, unit, frequency, sound, diaphragm, drive, bbc, profile, crossover, prototype, sound...
R&D Report 1986-03 : Design of a prototype moving-coil high-frequency loudspeaker drive unit. K.E. Randall A high-frequency loudspeaker drive unit (tweeter) suitable for use in a high-quality studio monitoring loudspeaker is described and the necessary manufacturing information provided. Design considerations are outlined and development problems discussed. Performance is assessed and possible improvements are suggested.
Topics: prototype, tweeter, bbc, khz, harmonic, characteristic, diaphragm, unit, current, design, drive...
Topics: prototype, tweeter, bbc, khz, harmonic, characteristic, diaphragm, unit, current, design, drive...
R&D Report 1990-05 : Digital audio editing: the development of a random access editor. D.Kirby, A.B. Gentles Whilst digital audio techniques offer many advantages over their analogue counterparts, the difficulty of editing digital recordings has detracted from the widespread adoption of this technology in broadcasting. The BBC has continued its research in this field with the development of a disc-based Digital Audio Editor to assess the capabilities of this type of equipment in a broadcast...
Topics: edit, audio, editing, editor, control, adjustment, edits, digital, processor, material, edit...
Topics: edit, audio, editing, editor, control, adjustment, edits, digital, processor, material, edit...
R&D Report 1990-01: Antennas for portable VHF-FM receivers. R.D.C. Thoday This report describes a number of compact antennas which have been considered as replacements for the standard whip antenna which is normally fitted to VHF portable receivers. A comparison made of their characteristics shows that, of the antennas considered in the survey, the quarter whip still provides the best sensitivity. However the normal-mode helix is a more convenient and compact antenna and is shown to perform...
Topics: antenna, receiver, helix, whip, sensitivity, tuning, ferrite, antennas, impedance, portable,...
Topics: antenna, receiver, helix, whip, sensitivity, tuning, ferrite, antennas, impedance, portable,...
R&D Report 1989-14 : Digital video: studio signal processing C.K.P. Clarke Several features of the digital component standard for television studios are described with a view to explaining the principles on which they are based and the modes of operation which were intended. For example, the sampling and filtering techniques were chosen to support multiple signal conversions with minimal loss of quality and the multiplexing techniques used were selected to simplify interconnections. The...
Topics: digital, signals, signal, analogue, mhz, luminance, component, coding, sampling, bbc, reference...
Topics: digital, signals, signal, analogue, mhz, luminance, component, coding, sampling, bbc, reference...
BBC Research and Development Reports
by
C.D. Mathers (editor)
texts
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R&D Report 1996-14 : WTDM Pilot Installation. A report on the work of RACE Project 2001 C.D. Mathers (editor) The BBC has led two RACE-sponsored projects to develop the technology for a fibre-optic based video signal router. In the first project, R1036, prototype equipment was developed; a demonstration in 1992 showed that optical routeing was not only feasible, but could accommodate different signal formats such as serial digital 625-line and uncompressed EU-95 HDTV. In a second RACE...
Topics: optical, wavelength, wtdm, network, pilot, nrk, installation, routeing, demultiplexer, equipment,...
Topics: optical, wavelength, wtdm, network, pilot, nrk, installation, routeing, demultiplexer, equipment,...
BBC Research and Development Reports
by
R.H. Evans, A.J. Bower
texts
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R&D Report 1996-06 : The Crystal Palace FM filler experiment R.H. Evans, A.J. Bower In some areas of London, listeners to BBC Radio National FM services had suffered from poor reception for some time. The problem was particularly severe immediately south of the River Thames where around one million people suffered with unsatisfactory reception on portable and car receivers. This was due to path blocking of the direct signal from the BBCâs Wrotham transmitter, located several miles south...
Topics: wrotham, crystal, filler, palace, mhz, transmitter, frequency, khz, transmitters, offset, khz...
Topics: wrotham, crystal, filler, palace, mhz, transmitter, frequency, khz, transmitters, offset, khz...
BBC Research and Development Reports
by
S.R. Ely
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R&D Report 1996-03 : MPEG video coding: A basic tutorial introduction S.R. Ely MPEG has been outstandingly successful in defining standards for video compression coding, serving a wide range of applications, bit-rates, qualities and services on a worldwide basis. The standards are based upon a flexible toolkit of techniques for bit-rate reduction. MPEG video coding uses a combination of motion-compensated interframe prediction (for reducing temporal redundancy) with Discrete Cosine...
Topics: prediction, dct, coding, picture, macroblock, coded, quantisation, mpeg, frame, coder, video...
Topics: prediction, dct, coding, picture, macroblock, coded, quantisation, mpeg, frame, coder, video...
BBC Research and Development Reports
by
K.W.T. Hughes, D.J. Whythe
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R&D Report 1959-13 : A transmitting aerial for propagation measurements in Band V (610-960 Mc/s). K.W.T. Hughes, D.J. Whythe A horizontally-polarized low-power transmitting aerial designed for propagation measurements in Band V (610-960 Mc/s) is described. The aerial was originally designed for operation in a narrow frequency band centred on 900 Mc/s. Later the frequency allocation was changed to 774 Mc/s, so that the aerial had to be modified. The measured results include radiation...
Topics: aerial, admittance, slotted, reflector, gain, slot, cylinder, radiation, horizontal, frequency,...
Topics: aerial, admittance, slotted, reflector, gain, slot, cylinder, radiation, horizontal, frequency,...
R&D Report 1954-14 : A new programme meter. E.R. Wigan This report looks at the design and making of a new performance meter.
Topics: scale, meter, optical, instrument, mirror, pointer, modulation, standard, frosted, light, programme...
Topics: scale, meter, optical, instrument, mirror, pointer, modulation, standard, frosted, light, programme...
BBC Research and Development Reports
by
M. Cooper
texts
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R&D Report 1954-12 : A servo-system for reducing amplitude modulation when the magnetic reproducing head is separated from the track. M. Cooper. In some applications of magnetic recording, such as storage or delay systems using magnetic disks or drums rotating at high speed, the magnetic heads must work out of contact with the medium. Any variation in the distance separating the heads and medium, such as that which would arise from eccentricity of the disk or drum, will give rise to...
Topics: modulation, reproducing, amplitude, magnetic, resonance, head, transducer, frequency, amplifier,...
Topics: modulation, reproducing, amplitude, magnetic, resonance, head, transducer, frequency, amplifier,...
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DESCRIPTION
A collection of BBC Research and Development reports and white papers, dating from the 1960s through to 1996.
Collection Info
- Addeddate
- 2011-11-02 04:12:47
- Collection
- additional_collections
texts
- Identifier
- bbc-rd-reports
- Mediatype
- collection
- Publicdate
- 2011-11-02 04:12:47
- Subject
- Research and Development
- Title
- BBC Research and Development Reports
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November 2
2011
2011
Jason Scott
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