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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BBC Research and Development Reports
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W.K.E. Geddes, M.W. Greenway, A.L. Newman and F.L. Ward
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R&D Report 1954-38 : Sound insulation and acoustics in the Belfast studio centre W.K.E. Geddes, M.W. Greenway, A.L. Newman and F.L. Ward. During the years 1952/3, all the studios in Broadcasting House, Belfast, except Studios Nos. 1 and 4, were given permanent acoustic treatment. This report summarises the results of acoustic measurement in all the studios, describes certain modifications which were made during the building work, and discusses conclusions of a general nature which resulted...
Topics: studio, studios, reverberation, cubicle, frequency, continuity, acoustic, insulation, measurements,...
Topics: studio, studios, reverberation, cubicle, frequency, continuity, acoustic, insulation, measurements,...
R&D Report 1983-09 : Digital television transmission: 34 Mbit/s PAL investigation. P.A. Ratliff, J.H. Stott The use of digital techniques for transmission has well-known advantages. However, transmission of video signals in digital form may not be economically attractive unless bit-rate reduction methods are used. Suitable methods are reviewed and three of them discussed in greater detail. The use of these methods is illustrated by the description of a system which conveys a...
Topics: digital, pal, transmission, bbc, blanking, signal, prediction, coding, dpcm, video, prediction...
Topics: digital, pal, transmission, bbc, blanking, signal, prediction, coding, dpcm, video, prediction...
R&D Report 1974-12 : Acoustic scaling: The effect on acoustic quality of increasing the height of a model studio H.D. Harwood, K.F.L. Lansdowne The effect on acoustic quality of raising the height of a model studio has been examined. The height was increased in two stages, firstly by 30% and then by a total of 60%. When, in each case, the reverberation time was brought back to its original figure by increasing the absorption, no change in sound quality over that originally obtained was...
Topics: reverberation, acoustic, bbc, studio, curve, equivalent, model, height, quality, spaced, roof...
Topics: reverberation, acoustic, bbc, studio, curve, equivalent, model, height, quality, spaced, roof...
R&D Report 1982-22 : L.F./M.F. radio-data: mush-area reception tests M.E. Bailey Programme-compatibility reception tests of a proposed data-transmission system for lf radio broadcasting are described. The tests demonstrate that the proposed system, which employs carrier phase-modulation, is compatible with programme reception in the "mush-areas" between co-channel, co-programme stations, provided that the data signals radiated from the stations are identical and...
Topics: data, modulation, signal, transmitters, westerglen, impairment, transmitter, reception, droitwich,...
Topics: data, modulation, signal, transmitters, westerglen, impairment, transmitter, reception, droitwich,...
BBC Research and Development Reports
by
C.J. White, D.W. Taplin, R.S. Sandell, J. Hall
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R&D Report 1956-38 : Low-power V.H.F./F/M. transmitters - Galashiels area site tests. C.J. White, D.W. Taplin, R.S. Sandell, J. Hall Two sites were tested in the Galashiels area. It was found that Lindean Moor would provide the better service and this site is therefore recommended. Tests on the reception of television sound indicated the probability of a reliable signal from the Kirk o' Shotts v.h.f. transmissions for rebroadcasting from Lindean Moor.
Topics: lindean, strength, moor, shotts, dryden, site, aerial, field, transmitter, kirk, television sound,...
Topics: lindean, strength, moor, shotts, dryden, site, aerial, field, transmitter, kirk, television sound,...
R&D Report 1968-12 : Bude 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, etn, receiving, pid, transmitting, installation, bude, bbc, transmitter, receiving...
Topics: aerial, band, etn, receiving, pid, transmitting, installation, bude, bbc, transmitter, receiving...
R&D Report 1968-47 : The subjective assessment of multiple co-channel television interference A. Brown The increase in protection ratio required by a number of simultaneous constant-level interfering signals, compared with the ratio required for a single interfering signal is considered. The results of some subjective tests are presented, and formulae are deduced to enable the additional protection ratio to be calculated, for related and unrelated types of interference
Topics: interferences, interfering, subjective, addition, signals, unrelated, impairment, interference,...
Topics: interferences, interfering, subjective, addition, signals, unrelated, impairment, interference,...
R&D Report 1984-04 : Filtering of the colour-difference signals in 4:2:2 YUV digital video coding systems. V.G. Devereux Specifications are proposed for the characteristics of the low-pass filters required at the input and output of the U and V channels of a 4:2:2 YUV digital video coding system. In such a system, the Y (luminance) signal is sampled at 13.5MHz and the U and V (colour-difference) signals are sampled at 6.75MHz as specified in CCIR Rec. 601. It has been concluded on both...
Topics: mhz, filters, digital, filtering, yuv, signals, frequency, filter, sampled, data, digital...
Topics: mhz, filters, digital, filtering, yuv, signals, frequency, filter, sampled, data, digital...
R&D Report 1987-15 : Theoretical and practical aspects of the "Functional Absorber" method of arranging sound absorbing panels. E.W. Taylor Measurements of the absorption of sound by functional absorbers (panels of porous material mounted so that both sides are exposed to the sound field) are described, the absorbers being arranged in a number of different configurations. The effect of increasing the surface density of the absorbing panels without significantly changing their...
Topics: absorption, absorbers, absorber, sound, panels, absorbing, reverberation, coefficient, arrangement,...
Topics: absorption, absorbers, absorber, sound, panels, absorbing, reverberation, coefficient, arrangement,...
BBC Research and Development Reports
by
P.A. Sarginson
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R&D Report 1996-02 : MPEG-2: Overview of the systems layer P.A. Sarginson The MPEG-2 Systems specification describes how MPEG-compressed video and audio data streams may be multiplexed together with other data to form a single data stream suitable for digital transmission or storage. This Report introduces the principles and terminology of the MPEG-2 Systems layer. The Report covers three main areas: Firstly, the structure of the multiplexes; secondly, the service information that may be...
Topics: elementary, stream, buffer, coder, programme, access, transport, decoder, video, streams,...
Topics: elementary, stream, buffer, coder, programme, access, transport, decoder, video, streams,...
R&D Report 1967-34 : The protection ratio required by an asymmetric-sideband, frequency-modulated monochrome television signal against an unwanted CW signal D.W. Osborne This report describes subjective tests which were made to determine the protection ratio required by an asymmetric-sideband, frequency-modulated monochrome television signal in order to reduce interference from an unwanted CW signal to a 'just not perceptible' level.
Topics: signal, interference, frequency, protection, monochrome, mhz, unwanted, ratio, required, ratios,...
Topics: signal, interference, frequency, protection, monochrome, mhz, unwanted, ratio, required, ratios,...
R&D Report 1984-12 : The susceptibility of aeronautical navigational aids to interference from adjacent-band broadcast transmissions. G.H. Millard Measurements to determine the susceptibility of some airborne navigation receivers to interference from v.h.f/f.m sound transmissions are described. The measurements were designed to investigate both the response to interference radiated in-band and to intermodulation in the receivers . The results of the measurements were submitted to an ITU...
Topics: receiver, ils, interference, intermodulation, frequency, signal, mhz, broadcast, transmissions,...
Topics: receiver, ils, interference, intermodulation, frequency, signal, mhz, broadcast, transmissions,...
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,...
R&D Report 1975-02 : A direct-reading chromaticity meter. K. Hacking, H.A.S. Philippart, T.A. Moore The principles and outline design of a tristimulus spot colorimeter, which gives a continuously updated read-out of the chromaticity co-ordinates and luminance of a surface colour are described. The colorimeter can be used to measure automatically the colour of the light reflected from a flat surface or emitted by a television screen, and was primarily developed as a research tool for...
Topics: chromaticity, tristimulus, luminance, readings, spectral, colour, colorimeter, channel, error,...
Topics: chromaticity, tristimulus, luminance, readings, spectral, colour, colorimeter, channel, error,...
R&D Report 1974-18 : MF aerials: The determination of ground-wave CMF and mean ground conductivity from radial field measurements by an optimisation technique J.L. Eaton A computing method for obtaining CMF and average ground conductivity values from sets of ground-wave measurements taken on radials from an MF aerial should be valuable in assessing the performance of new arrays in the future. A suitable optimisation technique which can be employed for this purpose and could be realised as a...
Topics: conductivity, values, optimisation, radial, permittivity, attenuation, interpolation, ground,...
Topics: conductivity, values, optimisation, radial, permittivity, attenuation, interpolation, ground,...
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 1992-09 : Low-frequency room responses: Part 2 -- Calculation methods and experimental results. R. Walker The development of a relatively simple method for predicting low- frequency responses for near-rectangular rooms based on the summation of modal responses and their coupling coefficients for the source and receiver positions is outlined. Comparisons between calculated and measured responses show that many of the response features can be reproduced. The question of optimum...
Topics: room, frequency, loudspeaker, frequencies, loudspeakers, octave, measured, mode, modes, response,...
Topics: room, frequency, loudspeaker, frequencies, loudspeakers, octave, measured, mode, modes, response,...
R&D Report 1964-11 : Measurement of the ratios of the currents flowing in the elements of a VHF transmitting aerial D.W. Osborne With the growth of the BBC television and v.h.f. sound services some transmitting aerials must of necessity comply with increasingly complex requirements in respects of the shape of the horizontal radiation pattern. It is difficult, however, to make satisfactory measurements of this pattern on the final aerial. In order to ensure that specified requirements are...
Topics: impedance, radiating, aerial, currents, perturbation, method, dipole, current, input, elements,...
Topics: impedance, radiating, aerial, currents, perturbation, method, dipole, current, input, elements,...
R&D Report 1973-41: Digital sound signals: Bit-rate reduction using an experimental digital compandor D.W. Osborne, M.G. Croll A previous investigation, using a simulation technique, indicated that considerable bit-rate reduction for the transmission of pulse-code modulated high-quality sound signals should be possible with a novel form of digital companding using a 'near-instantaneous' technique. A description is given of the design principles of an experimental model of a...
Topics: companding, quantising, digital, noise, compandor, companded, instantaneous, signal, tests,...
Topics: companding, quantising, digital, noise, compandor, companded, instantaneous, signal, tests,...
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 1976-28 : Hadamard transformation: Assessment of bit-rate reduction methods. C.K.P. Clarke This report is concerned with the bit-rate reduction of signals produced by Walsh-Hadamard transformation of PCM television signals. The main characteristics of the transform signals are outlined and the methods of linear and non-linear coding used to reduce their bit rate are described. It was found that, with linear coding, a slightly higher bit rate is required to describe the transform...
Topics: transform, bits, coefficients, signal, coding, hadamard, errors, signals, impairment, sampling,...
Topics: transform, bits, coefficients, signal, coding, hadamard, errors, signals, impairment, sampling,...
R&D Report 1987-14 : Improvements to a UHF rebroadcast television link suffering tidal fading: Countisbury UHF relay station. J.H. Moore The Countisbury UHF relay station serves the localities of Lynmouth and Lynton in Devon. For some time, the problems of co-channel interference and tidal fading have on occasion been evident. The report gives results obtained utilizing a new Rebroadcast Link (RBL) antenna array, which has improved very considerably the quality of signals received at this...
Topics: channel, array, antenna, countisbury, strength, relay, bbc, picture, phased, grade, video cassette,...
Topics: channel, array, antenna, countisbury, strength, relay, bbc, picture, phased, grade, video cassette,...
R&D Report 1989-02 : The control of the audible effects of ground vibrations in building structures. R. Walker, C.D. Mathers Over a period of about 8 years a number of investigations into the problems of vibration isolation, particularly of large structures, has been carried out, mostly in preparation for the development of a site (The Langham) which is subject to severe vibration interference from London Underground trains. The well-known limitations of some types of commercial vibration...
Topics: vibration, isolation, frequency, acoustic, studio, frequencies, measured, vibrations, resonant,...
Topics: vibration, isolation, frequency, acoustic, studio, frequencies, measured, vibrations, resonant,...
R&D Report 1991-10 : The airborne sound insulations of metal-framed partitions G.D. Plumb The sound insulation performances of several lightweight, metal- framed partitions were measured in Research Department's Transmission Suite. The aim was to produce a design for a new type of partition which was cheaper than the Camden, which is currently used throughout the BBC, while maintaining a comparable sound insulation. As a result of the studies, a partition is recommended for use as an...
Topics: partition, sound, insulation, single, mineral, plasterboard, leaf, double, camden, partitions,...
Topics: partition, sound, insulation, single, mineral, plasterboard, leaf, double, camden, partitions,...
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 1965-02 : Simultaneous long distance tropospheric propagation measurements at 560 Mc/s over the North Sea J.W. Stark Simultaneous field strength measurements on u.h.f. transmissions at 560 Mc/s and 774 Mc/s were carried out over the North Sea, on transmission paths ranging from 123 miles (198 mm) to 591 miles (960 km). The results show that with the same meteorological conditions the long-term received field strengths tend to be higher, although not to a significant extent, for...
Topics: signals, field, happisburgh, propagation, flamborough, measurements, signal, lerwick, hemsby,...
Topics: signals, field, happisburgh, propagation, flamborough, measurements, signal, lerwick, hemsby,...
R&D Report 1961-13 : A radio frequency transformer of continuously-variable ratio (The 'Heltran') C.G. Mayo, R.V. Harvey A radio-frequency transformer of continuously-variable ratio has been developed; it has been designed primarily for use in admittance bridges and is particularly useful for measuring the parameters of transistors.
Topics: reactance, helitran, transformer, error, impedance, coupling, variable, inductance, admittance,...
Topics: reactance, helitran, transformer, error, impedance, coupling, variable, inductance, admittance,...
R&D Report 1985-19 : Satellite sound broadcasting to fixed, portable and mobile radio receivers. J.H. Stott Direct broadcasting by satellite (DBS) of television signals to the home has received much attention recently; in contrast, less attention has been paid to sound-only (ie. radio) broadcasting from satellites. This Report reviews the present range of terrestrial sound broadcasting and explores the possible scope and technical feasibility of using satellites. Satellite broadcasting of...
Topics: broadcasting, satellite, antenna, frequency, terrestrial, orbit, sound, digital, geostationary,...
Topics: broadcasting, satellite, antenna, frequency, terrestrial, orbit, sound, digital, geostationary,...
BBC Research and Development Reports
by
L.C. Munn, R.D.A. Maurice
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R&D Report 1954-37 : NTSC colour television system: Interference on monochrome television receivers by the chrominance subcarrier. L.C. Munn, R.D.A. Maurice The tests described were undertaken during the period in July for which a simulated chrominance signal was radiated from the Alexandra Palace, and, a far as possible, the radiated signal was used for the purpose of the tests. Measurements were made at Kingswood on a group of six domestic television receivers, the main objects being: a....
Topics: subcarrier, chrominance, brightness, receivers, receiver, luminance, dot, raster, sound, signal,...
Topics: subcarrier, chrominance, brightness, receivers, receiver, luminance, dot, raster, sound, signal,...
BBC Research and Development Reports
by
G.H. Millard, R.H. Minns, G.D. Monteath
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R&D Report 1956-22 : Power measurement in the frequency range 30-1000 Mc/s. G.H. Millard, R.H. Minns, G.D. Monteath Laboratory equipment has been developed for measuring power over a wide range of levels in the frequency range 30-1000 Mc/s. A milliwatt meter using thermistors measures powers between 1 and 20 mW directly, and its use is extended to higher powers by means of dissipative attenuators and directional couplers. Each item of the equipment is fitted with connectors, suitable for...
Topics: power, directional, impedance, thermistors, measurement, attenuators, coupler, thermistor, voltage,...
Topics: power, directional, impedance, thermistors, measurement, attenuators, coupler, thermistor, voltage,...
R&D Report 1974-40 : Digital video: Error-correcting codes and a practical study of a Wyner-Ash error corrector J.H. Stott, A. Oliphant, D.W. Osborne When digital video information is carried on a communication circuit, some form of protection against the deleterious effects of errors is required. A concealment technique has limitations, particularly when DPCM coding is employed. The use of error correction coding, as distinct from error concealment, warrants investigation, and some of the...
Topics: parity, error, code, block, errors, data, codes, bits, digital, decoding, error rate, error...
Topics: parity, error, code, block, errors, data, codes, bits, digital, decoding, error rate, error...
R&D Report 1987-13 : Band II VHF antenna for home construction. S. Wakeling A wideband Band II Yagi antenna, suitable for home construction, has been designed using computer techniques. The antenna is intended for use as a domestic receiving antenna for VHF/FM sound broadcasting at frequencies in the range 88 to 108 MHz. Scale-model antennas were constructed and measured to verify the performance predicted by the computer. Finally, a full-scale Yagi antenna was constructed and its radiation...
Topics: antenna, yagi, dipole, vhf, antennas, ccir, design, impedance, element, folded, single dipole,...
Topics: antenna, yagi, dipole, vhf, antennas, ccir, design, impedance, element, folded, single dipole,...
R&D Report 1973-06 : Equipment for the transfer of digital video signals to paper tape C.K.P Clarke A digital computer can be used to simulate processing methods for the bit-rate reduction of digital television. To assess such methods, television signals must be converted to a form compatible with computer data-handling systems. This report describes equipment for transferring monochrome pulse-code modulation signals derived from a slide scanner to punched paper tape. One eight-bit word is...
Topics: signals, picture, digital, counter, sampling, samples, punched, bbc, paper, transfer, slide...
Topics: signals, picture, digital, counter, sampling, samples, punched, bbc, paper, transfer, slide...
R&D Report 1964-52 : Logarithmic amplifier using non-linear silicon diodes K.F.L. Lansdowne The principle of the construction of a logarithmic amplifier using semi-conductor Germanium diodes as logarithmic elements was described in Report B-056, Serial No. 1953/14. This report describes an amplifier using currently available silicon junction diodes.
Topics: logarithmic, amplifier, diodes, silicon, diode, output, circuit, impedance, oscilloscope, voltage,...
Topics: logarithmic, amplifier, diodes, silicon, diode, output, circuit, impedance, oscilloscope, voltage,...
R&D Report 1965-49 : Colour cameras: Variation of colour analysis with change of angle of incidence on to the colour splitter (dichroic tilt). W.N. Sproson, M.K.E. Smith Dichroic tilt, that is, variation in colour analysis over the optical image field, has been investigated for one type of prism-block colour analyser. Optical results are compared with those deduced from waveform measurements on a colour television camera. The observed dichroic tilt is found to be due to two causes, one of...
Topics: colour, aperture, optical, incidence, angle, lens, measurements, field, chromaticities, waveform,...
Topics: colour, aperture, optical, incidence, angle, lens, measurements, field, chromaticities, waveform,...
R&D Report 1992-13 : Measurement of display transfer characteristics using test pictures. A. Roberts There are three basic parameters which define the transfer characteristic of monitors: contrast, flare and gamma. Each of these can be measured, with varying degrees of accuracy, by a variety of methods. This Report attempts to clarify the definitions of the terms and to specify methods of measurement which give unique and repeatable results. Test pictures are described which permit...
Topics: measurement, flare, test, black, display, measurements, signal, contrast, displays, level, test...
Topics: measurement, flare, test, black, display, measurements, signal, contrast, displays, level, test...
R&D Report 1967-50 : Pulse-code modulation for high-quality sound-signal distribution: Appraisal of system requirements D. Howorth, D.E.L. Shorter For technical and economic reasons, the present network of lines used for distributing sound signals to transmitters at audio frequencies will eventually have to be replaced by some telecommunication system operating at frequencies above the audible range. For the immediate future, programme channels based on the existing carrier telephony...
Topics: signal, noise, transmission, quantizing, modulation, sample, ratio, system, coding, amplitude,...
Topics: signal, noise, transmission, quantizing, modulation, sample, ratio, system, coding, amplitude,...
R&D Report 1968-55 : New U.H.F. transmitting aerial for the Crystal Palace television station G.H. Millard The u.h.f. transmitting aerial at Crystal Palace has been replaced by a new aerial having better h.r.p. uniformity and v.r.p. null-filling. The old aerial was of the skew type mounted on the 1·32 m (4 ft 4 in.) square section of the tower. The new aerial is a panel type built as a top mast on the tower. The aerial changeover started after close-down on 15.8.68 and was completed...
Topics: aerial, transmitters, channel, type, horizontal, radiation, feeder, vision, bbc, transmitter,...
Topics: aerial, transmitters, channel, type, horizontal, radiation, feeder, vision, bbc, transmitter,...
R&D Report 1971-11 : Variation of medium-frequency sky-wave field strength with solar activity in Europe J.O. Drewery, P. Knight Abstract Medium-frequency sky-wave field strengths measured late at night during the solar cycle have been analysed. The reduction in field strength due to solar activity has been found to depend significantly on the distance between transmitter and receiver. A modified field-strength correction based on sunspot number and distance is proposed.
Topics: regression, sunspot, solar, strength, activity, distance, variation, field, coefficient,...
Topics: regression, sunspot, solar, strength, activity, distance, variation, field, coefficient,...
R&D Report 1994-16 : Digital Audio Broadcasting: Comparison of coverage at Band II and Band III. I.R. Pullen, P.J. Doherty, M.C.D. Maddocks A Digital Audio Broadcasting (DAB) system capable of reliable reception in vehicles and portables has been developed by the EUREKA 147 project. This Report describes a set of experiments performed to compare the coverage area when radiating a DAB signal of equal power in Band II and Band III. It is concluded that a slightly lower level of signal...
Topics: band, dab, signal, iii, variation, mhz, transmitter, coverage, map, bbc, transmitting equipment,...
Topics: band, dab, signal, iii, variation, mhz, transmitter, coverage, map, bbc, transmitting equipment,...
R&D Report 1962-51 : Report on the International Congress on Acoustics Copenhagen 1962. H.D. Harwood, F.L. Ward This is a report about the International Congress on Acoustics held in Copenhagen, Denmark in August 1962, which was attended by members of the BBC Research Department.
Topics: sound, reverberation, acoustics, insulation, author, acoustic, noise, frequency, papers,...
Topics: sound, reverberation, acoustics, insulation, author, acoustic, noise, frequency, papers,...
R&D Report 1963-21 : Service area of the Manningtree television transmitter. J.A. Butt, J.C. Westhorp This report presents the results of a field strength survey of the television transmitters at Manningtree. The service provided is very severely restricted by the high level of interference caused by United Kingdom co-channel stations and the Belgian television station located at Liege. Nevertheless, the principal towns in the service area are provided with a good service for a high...
Topics: manningtree, transmitter, strength, field, receiving, liege, aerial, interference, field strength,...
Topics: manningtree, transmitter, strength, field, receiving, liege, aerial, interference, field strength,...
R&D Report 1960-24 : The service areas of the Llanddona, Llangollen and Blaen-Plwyf VHF sound transmitters. G.I. Ross, R.C. Vercoe, M.J. Buckley, F.P. Raine The results of field strength surveys of the Llanddona, Llangollen and Blaen-plwyf v.h.f. sound transmitters are given. These transmitters, collectively, serve the more densely populated areas of North and West Wales but the mountainous nature of the country makes it inevitable that a few towns are beyond the service area of almost any...
Topics: llangollen, transmitters, llanddona, field, wales, strength, sound, transmitter, sound...
Topics: llangollen, transmitters, llanddona, field, wales, strength, sound, transmitter, sound...
BBC Research and Development Reports
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W.I. Manson
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R&D Report 1956-01 : The Philips moving-coil microphone Type EL.6040. W.I. Manson Laboratory tests have been carried out on two specimens of the Philips microphone type EL.6040. Measurements of frequency response, sensitivity, impedance and interference from magnetic fields have been made. The microphone has also been tested in the parabolic reflector PRB/2.
Topics: microphone, frequency, ohms, response, ohm, impedance, specimen, output, parabolic, philips,...
Topics: microphone, frequency, ohms, response, ohm, impedance, specimen, output, parabolic, philips,...
R&D Report 1963-34 : Service areas of the Redruth television and VHF sound transmitters. R.C. Vercoe, J.H. Causebrook, J.A. Carter The results of field strength surveys of the television and v.h.f. sound transmission are given in this report.
Topics: redruth, transmitters, television, sound, aerial, exceeded, field, strength, field strength, tiers,...
Topics: redruth, transmitters, television, sound, aerial, exceeded, field, strength, field strength, tiers,...
R&D Report 1966-64 : Transmitting aerials for the Sky (Skriaig) VHF television and VHF sound station D.W. Osborne, R.D.C. Thoday The Skye (Skriaig) relay station came into operation on the 14th March 1966. It provides a television and sound service to the Isle of Skye (with the exception of Portree), adjacent coastal areas of Invernessshire, Ross and Cromarty, most of the islands of Barra, Benbecula, North and South Uist and some areas in the south east of the Isle of Lewis.
Topics: aerial, transmitting, band, mast, templet, dipole, gain, horizontal, aerials, skye, transmitting...
Topics: aerial, transmitting, band, mast, templet, dipole, gain, horizontal, aerials, skye, transmitting...
R&D Report 1963-16 : Method of calibration of an experimental vertical aperture corrector D. Howorth This report describes a simple and convenient pulse method of calibrating the experimental vertical aperture corrector described in Research Department Report No. T-097. The calibration is obtained in the form of a factor from which the steady-state amplitude/frequency characteristics and the effect of the aperture corrector on signal-to-noise can be determined.
Topics: aperture, corrector, vertical, ratio, output, method, characteristics, calibration, signal,...
Topics: aperture, corrector, vertical, ratio, output, method, characteristics, calibration, signal,...
R&D Report 1964-20 : Considerations affecting the aperture and beam-tilt of UHF transmitting aerials P. Knight Curves are presented showing how field strength varies with distance for idealised uhf transmitting aerials of various apertures with different amounts of beam-tilt. From these curves conclusions are drawn regarding the maximum permissible aperture and the optimum beam-tilt for aerials erected on tall masts.
Topics: aerial, aerials, strength, transmitting, tilt, distances, aperture, field, apertures, lobe,...
Topics: aerial, aerials, strength, transmitting, tilt, distances, aperture, field, apertures, lobe,...
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 1965-37 : Class-AB amplifiers employing a complementary pair of transistors: Improved method for negative feedback J.B. Izatt This note describes a method of applying current negative feedback to transformerless audio class-AB transistor stages. The output impedance of the circuit is very high but the circuit may also be conveniently adapted to provide a matched output resistance, for example, for a 600-ohm line.
Topics: output, feedback, circuit, current, transistors, transistor, impedance, amplifier, distortion,...
Topics: output, feedback, circuit, current, transistors, transistor, impedance, amplifier, distortion,...
R&D Report 1986-14 : A variable-standards camera and its use to investigate the parameters of an HDTV studio standard. M.A. Stone A broadcast quality camera has been modified so that its field scan can be driven from an external source. With associated field stores to redistribute the video so generated both in time and in space, it has proved possible to investigate a wide variety of parameters that will affect the choice of a future HDTV studio standard. Such a choice should be made not...
Topics: field, hdtv, camera, scanning, interlaced, temporal, conversion, frequency, picture, integration,...
Topics: field, hdtv, camera, scanning, interlaced, temporal, conversion, frequency, picture, integration,...
R&D Report 1973-16 : Medium frequency directional aerials L.K. Bradley The principal design considerations for highly directional MF aerial arrays are presented together with a detailed calculation relating to a particular example of an in-line four-element directional array. Techniques for providing phase control and power splitting are also considered.
Topics: directional, phase, aerial, radiators, mast, arrays, impedances, bbc, required, aerials, aerial...
Topics: directional, phase, aerial, radiators, mast, arrays, impedances, bbc, required, aerials, aerial...
BBC Research and Development Reports
by
D.E.L. Shorter, W.I. Manson, E.R. Wigan
texts
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R&D Report 1957-10 : Some experiments on the subjective effect of limiting the upper frequency range of programmes D.E.L. Shorter, W.I. Manson, E.R. Wigan To obtain first-hand knowledge of the subjective effects of high-frequency band limitation, some tests have been carried out with Research Department staff of various categories as observers (thirty-four in all), using twelve types or recorded programme material. Low-pass filters having nominal cut-off frequencies of 10 kc/s and 12 kc/s...
Topics: observers, filter, frequency, observer, programme, experiments, filters, band, material,...
Topics: observers, filter, frequency, observer, programme, experiments, filters, band, material,...
R&D Report 1962-46 : The Service area of the Les Platons VHF sound transmitters (1962). M.J. Buckley, J.H. Stewart This report gives the results of a field strength survey of the v.h.f. sound transmissions radiated from Les Platons in Jersey and Guernsey. Most of Jersey gets a satisfactory service, but about one fifth of the island of Guernsey is not served. An Engineering Information Department (E.I.D.) survey showed that the v.h.f. service in Sark from Les Platons is satisfactory but...
Topics: les, platons, strength, transmitters, ville, aerial, guernsey, field, les platons, receiving, field...
Topics: les, platons, strength, transmitters, ville, aerial, guernsey, field, les platons, receiving, field...
R&D Report 1962-49 : Multiplex systems for stereophonic broadcasting G.J. Phillips, J.G. Spencer This report discusses the various systems which have been proposed for broadcasting stereophonic programme from a single v.h.f. transmitter. The results of laboratory tests on two systems are summarized. The first is the Zenith-G.E. system, adopted in 1961 by the F.C.C. for stereophonic broadcasting in the U.S.A. and more recently recommended by the European Broadcasting Union. The second is a...
Topics: stereophonic, subcarrier, monophonic, signal, reception, receiver, systems, system, modulation,...
Topics: stereophonic, subcarrier, monophonic, signal, reception, receiver, systems, system, modulation,...
R&D Report 1962-02 : The Colour response of monochrome television camera tubes C.B.B. Wood This report describes a number of subjective tests which were carried out to determine viewer's performances and tolerances for relative colour response in television cameras. Relative colour response is a term used to describe the characteristic by which the camera portrays the colours of the original scene as simple luminances in the black-and-white television image. Other tests were conducted to...
Topics: response, colour, observers, television, luminance, filters, orthicon, camera, neutral, image,...
Topics: response, colour, observers, television, luminance, filters, orthicon, camera, neutral, image,...
R&D Report 1966-06 : Subjective assessments of the portrayal of motion produced by simulations of field-store standards conversion R.E. Davies, S.J. Lent, M.T.A. Salter It is shown that the process of television standards conversion involving a change of field frequency degrades the portrayal of movement in the scene by introducing a jerky motion to certain types of movement. Experiments are described which show that in order to provide satisfactory portrayal of motion, when converting...
Topics: frames, fields, movement, conversion, standards, portrayal, observers, second, grade, picture,...
Topics: frames, fields, movement, conversion, standards, portrayal, observers, second, grade, picture,...
R&D Report 1967-03 : Field-store standards conversion: a controlled RF switch G.M. Le Courteur This report describes the development of a type of rf switch unit which is intended to control the rf signal routing in an experimental field-store standards converter. The switches are actuated by uni-directional control signals and contain built-in amplification so that they can be adjusted to have zero loss.
Topics: switching, switch, signal, impedance, input, element, diode, output, unwanted, switches, unwanted...
Topics: switching, switch, signal, impedance, input, element, diode, output, unwanted, switches, unwanted...
R&D Report 1965-39 : UHF aerials for the Hertford television relay station G.H. Millard A summary of the installtion of the UHF Aerials for the Hertford Television Relay Station.
Topics: aerials, transmitting, feeder, mounted, dipoles, oin, horizontal, aerial, distribution,...
Topics: aerials, transmitting, feeder, mounted, dipoles, oin, horizontal, aerial, distribution,...
R&D Report 1969-03 : Field strength near the ground at VHF and UHF: theoretical dependence on polarisation P. Knight Under ideal conditions, vertically-polarized vhf and uhf transmissions would give much higher field strengths close to the ground than horizontally-polarized transmissions. Although the theoretical difference between the two polarizations could be as much as 30 dB at ground level, it decreases rapidly with height and is less than 3 dB at a height of one wavelength.
Topics: ground, field, dielectric, polarization, ratio, aerial, theoretical, reflection, height, heights,...
Topics: ground, field, dielectric, polarization, ratio, aerial, theoretical, reflection, height, heights,...
R&D Report 1967-55 : Digital methods in television G.D. Monteath, V.G. Devereux This report indicates some of the advantages to be gained by converting television waveforms to trains of binary digits before signal processing operations such as standards conversion are carried out. These operations could then be effected by digital storage and logic circuits, the main advantages being reliability and freedom from distortion. A brief description is given of possible methods of performing...
Topics: digital, signal, television, signals, binary, store, conversion, converter, analogue, required,...
Topics: digital, signal, television, signals, binary, store, conversion, converter, analogue, required,...
R&D Report 1967-29 : An analogue to digital conversion system and paper tape transcoder for processing acoustic signals M.E.B. Moffat A system has been devised to improve the technique of certain kinds of acoustical measurements concerned with sound diffusion and decay. Two main functions are incorporated. The first permits analogue to digital conversion of an electrical signal with recording on eight-track perforated paper tape at speeds of up to 120 characters per second. The second...
Topics: punch, parity, transcoder, pulse, data, digital, signal, tape, bistable, gates, octal counter,...
Topics: punch, parity, transcoder, pulse, data, digital, signal, tape, bistable, gates, octal counter,...
R&D Report 1976-03 : LF and MF propagation: The effect of earth curvature on sea gain. P. Knight If an l.f or m.f aerial is situated near the sea, the strength of sky-wave signals is increased by sea gain. The report shows that Earth curvature has a significant effect at lf and mf on sea gain at coastal sites but has less influence on the reduction of sea gain which occurs when an aerial moves inland or when the sea is of limited extent.
Topics: sea, curvature, gain, earth, path, conductivity, propagation, aerial, ground, distance, reflection...
Topics: sea, curvature, gain, earth, path, conductivity, propagation, aerial, ground, distance, reflection...
R&D Report 1976-21 : A circularly-polarised aerial for satellite reception. C. Gandy A circularly-polarised feed aerial for a 2.44m parabolic reflector was designed and constructed to form the basis of a satellite receiving station. Waveguide components and a hybrid-mode scalar-horn aerial were used, with a facility for the reception of either sense of polarisation. The cross-polar isolation was found to be 30 dB, and with a 2.44m parabolic reflector the aerial gain was estimated to be 40...
Topics: feed, aerial, waveguide, aperture, polariser, mode, coupler, circular, axial, orthogonal,...
Topics: feed, aerial, waveguide, aperture, polariser, mode, coupler, circular, axial, orthogonal,...
R&D Report 1977-16 : MF lattice planning on a spherical earth. P.A. Laven Planning of frequency assignments using a lattice network on a plane surface offers a uniform number of assignments per unit area and uniform levels of interference for each transmitter. A study of the problem of fitting a lattice network to the spherical surface of the Earth, without affecting these basic properties, shows that the representation of the Earth by an icosahedron is not a satisfactory solution and that...
Topics: lattice, spherical, plane, assignments, network, polyhedron, sphere, interference, surface,...
Topics: lattice, spherical, plane, assignments, network, polyhedron, sphere, interference, surface,...
R&D Report 1977-14 : Permissible timing jitter in broadcast PAL colour television signals. V.G. Devereux The report considers the results obtained from a number of different sets of subjective tests concerning tolerances for timing instabilities (referred to as jitter) in broadcast PAL colour-television signals. The magnitude of the timing errors considered is of the order of a few nanoseconds. These errors produce perturbations in the saturation and hue of colour areas of a displayed...
Topics: jitter, series, test, static, phase, sinusoidal, frequency, magnitude, tests, impairment, jitter...
Topics: jitter, series, test, static, phase, sinusoidal, frequency, magnitude, tests, impairment, jitter...
R&D Report 1977-26 : CEEFAX: evolution and potential J.R. Chew The development of the CEEFAX information broadcasting system from initial work in 1966 to the end of the two-year experimental period in 1976 is described. The background to the choice of transmission and display parameters is given, together with details of laboratory and field experiments. Particular emphasis is given to the selection of the addressing and coding systems to give reliable reception throughout the normal...
Topics: ceefax, transmission, display, data, graphics, receiver, transmitted, characters, television,...
Topics: ceefax, transmission, display, data, graphics, receiver, transmitted, characters, television,...
R&D Report 1969-52 : A p.c.m. sound-in-syncs distribution system: combination and separation of sound and video signals C.J. Dalton This report, one of a series of four, gives the basic requirements and simple descriptions of experimental equipment for the combination and separation of sound and video signals as used in the 'sound-in-syncs' system for conveying a sound signal together with a video signal along a video link. Performance figures for the equipment are given and from the...
Topics: sound, pulse, signal, video, separator, detection, pulses, sync, separation, distribution, sound...
Topics: sound, pulse, signal, video, separator, detection, pulses, sync, separation, distribution, sound...
R&D Report 1972-40 : Pulse-code modulation for high-quality sound-signal distribution: Subjective effect of digit errors G.R. Mitchell, M.E.B. Moffat In a companion report (Report No 1972/18) a digit-error-protection technique was recommended for use in a multiplex pulse-code modulation (PCM) system for high-quality sound-signal distribution. The technique is briefly summarised in the present report. Tests have been carried out with and without the application of the protection technique to...
Topics: error, impairment, test, probability, tests, errors, grade, subjective, programme, intelligibility,...
Topics: error, impairment, test, probability, tests, errors, grade, subjective, programme, intelligibility,...
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 1992-02 : On minimising noise problems caused by passenger lifts in studio centres. C.D. Mathers A number of passenger lifts have been investigated as sources of noise and vibration. Typical measured results are presented, and a number of problems and solutions are discussed. Finally, some general recommendations are listed, indicating how noise nuisance may be avoided or remedied.
Topics: pump, lift, vibration, hydraulic, ram, slab, lifts, noise, measurements, mounts, pump vibration,...
Topics: pump, lift, vibration, hydraulic, ram, slab, lifts, noise, measurements, mounts, pump vibration,...
R&D Report 1987-19 : Designing variable-length codes with good error-recovery properties. M.J. Knee An algorithm for calculating the expected resynchronisation time of a variable-length code following a transmission error is described. The results of calculations based on examples are used, together with insights gained from a simplification of the algorithm, to determine the effect on the expected resynchronization time certain easily recognizable design features of codes. The report...
Topics: code, error, codes, codewords, resynchronization, probability, algorithm, codeword, sequence,...
Topics: code, error, codes, codewords, resynchronization, probability, algorithm, codeword, sequence,...
R&D Report 1983-03 : Subjective evaluations of recent productions of television with stereophonic sound. P.S. Gaskell A series of subjective tests has been conducted to assess the improvement given by stereophonic sound with television in comparison to the conventional monophonic equivalent. The test material consisted of extracts from eight, recently produced, television stereo programmes. They represented the wide range of BBC television programme output and, since some types of programme...
Topics: stereo, sound, viewers, bbc, viewer, extracts, programme, television, peterson, tests, programme...
Topics: stereo, sound, viewers, bbc, viewer, extracts, programme, television, peterson, tests, programme...
BBC Research and Development Reports
by
T.W. Bennington
texts
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R&D Report 1954-09 : Information on short wave propagation conditions from reception results on fixed frequencies. T.W. Bennington Regular hourly observations made at Panorama, South Africa, on reception of five fixed frequencies from Standard Frequency Station WWV have been analysed to obtain information on propagation conditions and their daily and seasonal variations, for comparison with those given by world charts of predicted MUF. The results indicate that the predications agree well...
Topics: reception, muf, frequencies, gmt, propagation, signal, frequency, predicted, luf, panorama, sinpo...
Topics: reception, muf, frequencies, gmt, propagation, signal, frequency, predicted, luf, panorama, sinpo...
R&D Report 1962-18 : The Visibility of delayed images in television. G.F. Newell, D. Howorth This report describes subjective measurements of the visibility of delayed images superimposed on a 405-line television picture. The visibility of these images, which can occur as a result of a reflected signal caused by a mast or other reflecting object in the propagation path of the direct signal, depends on the amplitude and phase of the reflected signal relative to those of the direct signal....
Topics: excerpt, delayed, signal, observers, visibility, reflected, excerpts, direct, grades, amplitudes,...
Topics: excerpt, delayed, signal, observers, visibility, reflected, excerpts, direct, grades, amplitudes,...
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DESCRIPTION
A collection of BBC Research and Development reports and white papers, dating from the 1960s through to 1996.
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- Addeddate
- 2011-11-02 04:12:47
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- Publicdate
- 2011-11-02 04:12:47
- Subject
- Research and Development
- Title
- BBC Research and Development Reports
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2011
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