Skip to main content
Internet Archive's 25th Anniversary Logo

BBC Research and Development Reports

A collection of BBC Research and Development reports and white papers, dating from the 1960s through to 1996.



rss RSS

1,337
RESULTS


Show sorted alphabetically

Show sorted alphabetically

SHOW DETAILS
up-solid down-solid
eye
Title
Date Published
Creator
R&D Report 1977-41 : A digital split-band compandor for 64 kbit/s coding of speech with s 7kHz bandwidth. W.I. Manson, D.W. Stebbings This Report describes a three-channel split-band digital compandor arrangement for coding a 7 kHz speech signal for transmission at 64 kbit/s. It was not practicable at the time to construct equipment for real-time evaluation, but the performance of a simulation has been assessed. The results obtained are regarded as promising, but the performance was...
Topics: khz, digital, companding, coding, system, compandor, sampling, speech, bandwidth, technique,...
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,...
R&D Report 1966-48 : Transmitting aerials for the Weardale VHF television and VHF sound station D.W. Osborne, R.D.C. Thoday, J.P. Crean The Weardale relay station came into operation on 21st February 1966. It provides a television and v.h.f. sound service to Wolsingham, Frosterley, Stanhope, Westgate, Eastgate and other small communities in the area.
Topics: horizontal, aerial, band, templet, gain, transmitting, dipole, tiers, carrier, weardale, effective...
R&D Report 1964-45 : Transmitting aerials for the Okehampton VHF television and VHF sound station D.W. Osborne A brief summary of the installation of Okehampton Relay Station.
Topics: aerials, transmitting, okehampton, vertical, aerial, templet, gain, horizontal, band, carrier,...
R&D Report 1973-07 : Digital video: Differential coding of PAL signals based on differences between samples one subcarrier period apart V.G Devereux Methods for reducing the bit-rate required for digital coding of System I (PAL 625-line) video signals by means of differential pulse code modulation are discussed. The subjective effect of various DPCM and hybrid DPCM/PCM coding systems have been investigated with a view to finding a system giving broadcast quality pictures. All the systems...
Topics: quantising, sample, prediction, signal, coding, values, coder, transmission, errors, bbc, pulse...
R&D Report 1964-47 : Impact of users' needs on the design of data processing systems R.W. Lee, M.E.B. Moffat The conference was held at the Heriot-Watt College Edinburgh from 31st March to 3rd April 1964. The conference papers were divided into four main categories (a) Programming and Operating Systems, (b) Storage technology and organization, (c ) Maintenance, (d) Input, output and Man-Machine Communications.
Topics: computer, data, processing, computers, digital, large, programme, magnetic, author, processer,...
R&D Report 1967-31 : Lark Stoke UHF relay station: Summary of installation G.H. Millard A brief data sheet detailing frequencies, equipment installed, radiation characteristics etc, including graphs of horizontal and vertical radiation patterns.
Topics: mhz, stoke, lark, radiation, transmitter, relay, power, vertical, installation, technological, lark...
R&D Report 1986-09 : Digital television routing systems: an experimental optical switching matrix. R.P. Marsden, J.T. Zubrzycki A mechanical-optical switching matrix has been built as part of a study into the distribution of digital video signals within a television studio centre. The matrix is based on a 10-by-10 arrangement, of which two sections, one 4-by-4 and the other, 1-by-10, have been populated. Details of the construction and operation of the matrix are given. The matrix performs...
Topics: matrix, optical, fibre, beam, routing, loss, mirrors, mirror, tap, switching, television studio,...
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,...
R&D Report 1996-07 : EUREKA 147: Subjective assessment of the error performance of the DAB system, including tests at 24 kHz audio sampling frequency. M. Lever (CCETT), J. Richard (CCET), N.H.C. Gilchrist This Report describes tests carried out by the authors and other members of Eureka 147 Working Group âAâ, to assess the performance of the DAB (Digital Audio Broadcasting) system with a low carrier-to-noise ratio at the receiver. The tests were conducted using a number of listeners to...
Topics: uep, mono, stereo, joint, audio, tests, rayleigh, eep, onset, impairment, bit rate, rural rayleigh,...
R&D Report 1965-16 : Transmitting aerials for the Larne VHF television and VHF sound station D.W. Osborne The Larne relay station came into operation on 5th April 1965. It provides a television and v.h.f sound service to Larne.; the television coverage also extends to Ballylimford and Magheramorne.
Topics: aerial, band, horizontal, aerials, dipole, tower, templet, transmitting, support, gain, effective...
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...
R&D Report 1990-15 : The design and application of modular, acoustic diffusing elements. R. Walker The requirements for and the advantages of a modular acoustic diffusing element are described. This module was intended to complement the existing range of acoustic absorbing elements already in widespread use. The theoretical background to the principles is summarised, based on the published work of M.R. Schroeder, and a design for such a module is discussed. The performance of the resulting...
Topics: acoustic, diffusers, bbc, primitive, frequency, modular, diffusing, sequence, module, diffuser,...
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,...
R&D Report 1964-68 : Reflectors in concert halls and orchestral studios T. Somerville, C.L.S. Gilford This report describes the modifications to the stage carried out in Southampton Guildhall to improve the acoustics. The modifications consisted of diffusing surfaces which appear to have been effective in enabling the performers to hear each other, and in improving the tonal quality for the audience.
Topics: reverberation, diffusion, concert, diffusing, southampton, reflectors, orchestral, orchestra,...
R&D Report 1974-13 : Walsh-Hadamard transformation of television pictures R. Walker, C.K.P. Clarke This report gives a summary of the basic theoretical background of Walsh-Hadamard transformation and describes a method by which the process may efficiently be carried out on real-time television signals. The use of such a transformer, augmented by signal measurements carried out in non-real time, is described. The use of the technique as a means of television bit-rate reduction is discussed.
Topics: transform, bits, transformer, transformation, matrix, inverse, walsh, hadamard, vector, input,...
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,...
R&D Report 1984-19 : L.F. radio-data: specification of BBC phase-modulated transmissions on long-wave. D.T. Wright The BBC long-wave AM transmitter network carries a low bit-rate data signal, in addition to the normal programme signal modulation. The data signal is conveyed by phase-modulation of the carrier, the signal parameters being chosen so that there is no disturbance to reception on existing domestic receivers. This Report describes the data signal and includes details of both the...
Topics: data, block, code, transmitted, cyclic, bits, crc, blocks, prefix, biphase, biphase symbol, binary...
R&D Report 1986-11 : A conditional access system for direct broadcasting by satellite. S.M. Edwardson Work is in progress throughout the world in connection with the setting up of systems for Direct Broadcast by Satellite (DBS). The need for the financing of such systems and the services they will carry has led to the conclusion in some countries that they will be of the "Conditional Access" kind. This means that they will carry signals that will be scrambled and be recovered only...
Topics: signals, scrambling, signal, receiver, authorization, validation, picture, dbs, data, encryption,...
R&D Report 1995-12 : Archive retrieval: Techniques for image enhancement J.C.W. Newell This report describes image processing techniques which could be used to improve the perceived resolution of archive video recordings. It has been found that the benefits obtained using linear methods are limited. However, a non-linear method is described which can be used to sharpen edges. The technique has been used successfully to enhance images with a significantly smaller visible increase in ringing...
Topics: signal, process, linear, frequency, filter, correction, edges, sharpening, noise, edge, aperture...
R&D Report 1960-22 : The UHF Television survey of 1957/8: a comparison of the field strengths measured by the BBC mobile Laboratory during the series A and series B tests E.W. Taylor This report describes the field strength measurements made by the B.B.C. mobile laboratory at the sites chosen for subjective assessments of picture quality. Comparison of the measurements made during the Series B tests with those made during the Series A tests shows that the two sets of measurements were...
Topics: series, radial, band, tests, median, field, ratio, measured, site, mobile, showing distribution,...
R&D Report 1955-11 : Television service for West Wales site tests at Pant Gwyn, Blaen-Plwy and Mynydd Bach. R.D. Pittilo, C.J. White, J. Hall, S.J. Ashdown, C.S. Dobson This report shows that of the three sites tested, one at Blaen-plwy 4 miles (6.5 km) south of Aberystwyth will give the best television coverage in West Wales. It is not possible to receive a reliable signal from Wenvoe at this site for direct relay and an intermediate link will be required.
Topics: aerial, site, mynydd, pant, height, bach, wenvoe, strength, mast, field, west wales, wales site,...
R&D Report 1962-24 : The Distribution of current on cylindrical radiating dipoles. W. Wharton The distribution of current on a dipole comprising cylindrical conductors is approximately sinusoidal, but in certain problems a more accurate solution is required. A number of theoretical attempts have been made to obtain a better approximation and are in reasonable agreement. These methods are, however, laborious to apply in practice and are also limited in application. In this report a simple...
Topics: current, unipole, perturbation, distribution, input, equation, sinusoidal, impedance, method,...
R&D Report 1964-02 : UHF field strength distributions at typical domestic receiving locations C.P. Bell The results of series of field strength measurements made both within and in the immediate vicinity of a group of typical suburban houses are stated. Based on experience that a receiving aerial mounted outdoors at 30 ft (9.1 m) above ground level (a.g.l.) gives a satisfactory service if the ambient field strength is not less than 70 dB above 1 uV/m (70 dB(uV/m)), it is concluded that a...
Topics: aerial, field, strength, aerials, measured, channel, receiving, measurements, grade, median,...
R&D Report 1965-15 : Transmitting aerials for the Toward VHF television and VHF sound station D.W. Osborne The Toward relay station came into operation on 22nd March 1965. It provides a television and v.h.f sound service to; Rothesay and the western half of Bute, the Northern half od Cumbrae, Largs and the mainland coast generally from Fairlie to Inverkip, Toward Point.
Topics: aerial, transmitting, band, gain, templet, horizontal, aerials, tower, polarization, feeders,...
R&D Report 1970-12 : Automatic registration feasibility study: The use of sampling techniques for vertical registration error detection J.D. Lunn A colour camera registration error detector has been described (in BBC RD 1969/50) whose output indicates the horizontal offset of one scanned image with respect to another. The equipment to be described is based on the same basic principles but, by using electronic sampling techniques, indicates the vertical offset of one image with respect to...
Topics: detector, vertical, registration, sampling, output, offset, interpolation, error, responses,...
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,...
R&D Report 1964-28 : Transmitting aerials for the Shetland VHF television and VHF sound station D.W. Osborne A brief summary of the installation of Shetland Relay Station.
Topics: aerial, gain, band, shetland, aerials, sound, feeders, templet, carrier, transmitters, effective...
R&D Report 1973-30 : Television reception over sea paths: The effect of polarisation P.A. Laven Fading of UHF signals on oversea paths within the horizon can occur because of interference between the direct and sea-reflected signals. Comparisons of transmissions using horizontal polarisation (HP) and vertical polarisation (VP) have been made on short paths affected by fading. The results indicate that unacceptable fading can occur on either polarisation, although fading on VP is generally...
Topics: polarisation, amplitude, fading, reflection, grazing, receiving, elliptical, reflected, direct,...
R&D Report 1991-13 : Developments in multichannel sound for HDTV D.J. Meares New sound systems are being developed to accompany HDTV which will generate better listening experiences for the audience. This Report outlines some of the intended improvements and, by way of an example, illustrates some of the production problems that will have to be overcome before the proposals can be implemented. It also discusses the domestic impact of the systems.
Topics: sound, surround, hdtv, bbc, channel, multichannel, channels, loudspeakers, loudspeaker, frontal,...
BBC Research and Development Reports
texts

eye 251

favorite 0

comment 0

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,...
R&D Report 1964-03 : Effects of polarization on a medium-frequency sky-wave service, including the case of mule-hop paths G.J. Phillips, P. Knight Ionospheric propagation at medium frequencies depends almost entirely on the ordinary wave which is, in general, elliptically polarised. This report describes coupling losses which occur when this wave is transmitted and received with vertical aerials. It also discusses additional losses caused by changes of polarisation when intermediate Earth...
Topics: polarization, wave, reflexion, coupling, mode, frequency, magnetic, polarized, axis, propagation,...
R&D Report 1974-34 : Colour television displays: Error diagrams for evaluating the reproduced chromaticities of some test colours E.W. Taylor Sets of charts or 'error diagrams' are provided, which enable the errors in the reproduction of each of seventeen test colours to be obtained, when this reproduction is effected by a colour television display in which one or more phosphors have chromaticities differing from the specified System I values. The error in test-colour reproduction is given...
Topics: chromaticity, phosphor, error, chromaticities, test, colour, bbc, aoaaa, phosphors, simn, error...
R&D Report 1978-26 : Digital sound signals: tests to compare the performance of five companding systems for high-quality sound signals. N.H.C. Gilchrist A number of digital companding systems have been proposed for saving bit-rate in digital sound transmission. All of these systems introduce a degree of programme-modulated noise into the sound signal, and this Report describes tests which have been carried out to compare the resulting subjective impairment. The performance of five...
Topics: companding, digital, tests, noise, systems, subjective, coding, tdf, bbc, sound, modulated noise,...
R&D Report 1979-14 : Digital recording using hologram arrays: optical design for an experimental 100 Mbit/s recorder. K. Hacking, J.L. Riley The general arrangements used in the construction of an experimental recorder are outlined and several optical design features of the proposed system are discussed in detail. These include the concepts underlying the design of a digit-beam array forming a hologram 'page' and the optical methods for recovering the digital information. The optimum...
Topics: beam, deflector, optical, array, aperture, scanning, lens, hologram, recording, digital, optical...
R&D Report 1988-14 : On the design of loudspeakers for broadcast monitoring. C.D. Mathers By designing its own monitoring loudspeakers for about the past forty years, the BBC has achieved a degree of continuity and consensus in a subject where there are almost as many opinions as there are designers. This report describes the approach that has evolved within the Corporation towards design and assessment, and indicates how calculation and objective measurement are supplemented by experience...
Topics: loudspeaker, bbc, design, frequency, damping, coil, acoustic, unit, diaphragm, drive, relative...
R&D Report 1965-06 : Performance of 10 to 1 zoom lens for image orthicon format: (Type 10 x 35B No. 1095308). K.J. Wright The characteristics of the redesigned zoom lens type 10 x 35B have been measured. These include modulation transfer function, vignetting, transmission and veiling glare and geometrical distortion. An overall assessment based on sharpness and vignetting is given, and comparisons are made with production lenses type 10 x 35B and with other zoom lenses.
Topics: lens, focal, aperture, zoom, length, varotal, transfer, modulation, spatial, distortion, test...
R&D Report 1968-18 : U.H.F. relay station aerials inside 914 mm diameter glass-fibre cylinders J.L. Eaton, A.D. Olver The BBC aerial for UHF relay stations was designed for operation inside a glass-fibre cylinder of 387 mm diameter. More recently a new requirement has arisen to house the aerial inside a 914 mm diameter cylinder to permit access. An investigation was therefore carried out to study the effect of a 914 mm cylinder on the performance of the aerial. A position of the aerial...
Topics: cylinder, mhz, aerial, dielectric, dipole, spacing, band, diameter, impedance, sin, dielectric...
R&D Report 1973-11 : MF network planning: The coverage under daytime conditions from a network of transmitters arranged in a uniform lattice R.A. Rowden The report collates definitions of the various types of network where transmitters are arranged geographically over an area and a given number of frequency channels is available for use. The method of calculation of the coverage is described and useful formulae stated. An exemplary tabulation, for limited ranges of power, frequency, ground...
Topics: kms, transmitters, coverage, network, khz, equilateral, transmitter, frequency, service range,...
R&D Report 1973-10 : An automatic shot-change detector for telecine J.R. Sanders, M. Weston A system for the detection of shot changes occurring in films reproduced by telecine has been developed. This information is required for pre-programmed systems of telecine control and was, in the past, always obtained by visual inspection of the film in order to make a record, usually on paper tape, of the positions in the film at which shot changes occurred. The detector described in this report...
Topics: shot, integrator, detector, output, pulses, telecine, signal, film, bbc, video, successive fields,...
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...
R&D Report 1976-05 : Reduction of mush-area distortion in common-frequency MF transmitter networks. D.J. Whythe The present crowding of the medium-wave band has made it necessary for several transmitters that broadcast a common programme to share a common carrier frequency and, in many cases, their service areas considerably overlap. Daytime reception is impaired by ground-wave interference between pairs of such transmitters in regions (so called 'mush' areas) where their field-strength...
Topics: modulation, transmitters, phase, brookmans, reception, ratio, delay, distortion, transmitter,...
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,...
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,...
R&D Report 1982-04 : Relationships between normal-incidence and statistical absorption coefficients. E.W. Taylor The theory underlying the absorption of sound at normal incidence is summarised and its extension to include absorption at random incidence is discussed. A chart of the relationships between the normal-incidence and random-incidence or 'statistical' absorption coefficients is given, and a method of using this chart to obtain values of the statistical absorption coefficient from...
Topics: impedance, sound, absorption, equation, surface, pressure, coefficient, acoustic, velocity,...
C.D. Mathers, K.F.L. Lansdowne Exposure to high sound levels can cause damage to the auditory system, either gradually over a period of time, or, in the case of very intense sounds, instantaneously. Particular care is therefore required in the use of headphones, which are capable of generating much higher effective sound levels than loudspeakers. This report summarises the results of a series of tests which show that headphone wearers tend to listen at significantly higher levels than...
Topics: headphone, hearing, levels, headphones, tests, artificial, ear, sound, loudspeakers, listening,...
R&D Report 1981-04 : VHF radio-data: experimental BBC transmissions. S.R. Ely This report describes in detail a new system for transmitting data signals from vhf radio-broadcast transmitters along with the normal sound-programme signal. These data signals are primarily intended to aid radio listeners in tuning their receivers to a desired station or programme. These data signals are primarily intended to aid radio listeners in tuning their receivers to a desired station or programme. They...
Topics: block, data, synchronisation, code, crc, khz, transmitted, subcarrier, bbc, decoder, biphase...
R&D Report 1981-07 A digital field strength measuring receiver for l.f. and m.f. A.P. Robinson, J.H. Causebrook
Topics: receiver, aerial, field, calibration, tuning, digital, bbc, frequency, oscillator, khz, department...
R&D Report 1985-09 : Digital television routing systems: an introduction to integrated optical waveguide techniques and devices. J.P. Willson The development of a digital standard for the coding of component video signals (CCIR Rec. 601) has raised the problem of the appropriate technology to be used for the routing and distribution of such signals within a television studio centre. Optical fibres offer a number of advantages over coaxial cable, such as high bandwidth, low loss, and small...
Topics: optical, switch, coupler, waveguides, waveguide, lithium, directional, integrated, array,...
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,...
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,...
R&D Report 1957-04 : The service area of the Pontop Pike television transmitter. D.W. Taplin, D.F. Cooney, I. Rhodes A field strength survey of the Pontop Pike television transmission has been carried out. The service provided conforms well with that expected from site test measurements. The heavily populated industrial areas of Tyneside area well served. The Tees-side area is provided with a fair service.
Topics: pontop, pike, transmitter, transmission, strength, contours, field, median, pontop pike, populated,...
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,...
R&D Report 1954-04 : Some problems influencing the design of a machine for the high-speed dubbing of magnetic recordings. P.E. Axon The purpose of this report is to give an appreciation of some of the problems which will be met with in an alternative approach to tape duplication by the process of high-speed multi-tape dubbing.
Topics: tape, recording, dubbing, spool, reproducing, tension, shaft, magnetic, required, frequencies,...
R&D Report 1963-20 : Photo-electric lens-testing bench. W.N. Sproson, K. Hacking A photo-electric lens test bench capable of measuring lenses of focal length from 12 mm to 1 m is described. Designed specifically for television applications, it gives the 'optical transfer" curve automatically plotted on recording paper, using the sine-wave analyser described by Hacking. Facility is also provided for the recording of the "spread function". The angular field is somewhat in...
Topics: optical, analyser, slit, lens, spatial, modulation, image, bench, measurements, function, fourier...
R&D Report 1971-34 : Channel 21 television transmissions: Interference to services below 470 MHz R.V. Harvey Some types of communication equipment that are used by public services at frequencies in the private mobile radio band operate just below 470 MHz. The results are given of laboratory tests to determine the susceptibility of this equipment to interference from lower-sideband radiation from Channel 21 television transmitters. The operational factors affecting the incidence of...
Topics: interference, mhz, khz, frequency, sideband, channel, transmitter, receiver, television, signal,...
R&D Report 1963-28 : Transmitting aerials for the Ashkirk television and VHF sound station. D.W. Osborne, R.D.C. Thoday The design of the Band I and Band II transmitting aerials for the Ashkirk station has been based on theoretical predications and model measurements which are described in this report. The aerials are mounted on a 750 ft (228m) stayed mast of 4 ft (1.22 m) square cross-section.
Topics: aerial, band, dipole, currents, aerials, radiating, mast, dipoles, horizontal, templet, field...
R&D Report 1964-10 : Visit to NV Philips Gloeilampenfabrieken, Eindhoven 15 to 17 January 1964. D.R. Morse, C.B.B. Wood Members of the department visited Philips in Eindhoven in january 1964 to discuss the technical performance of the Plumbicon Camera Tube. This report is an account of this visit.
Topics: plumbicon, philips, tube, bbc, production, peto, tubes, camera, monochrome, colour, colour...
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,...
R&D Report 1963-56 : Performance of certain television receivers designed for the 525/60 standard when operated from a 50 c/s mains supply. G.C. Wilkinson This report describes subjective tests on the performance of three domestic receivers, all designed to operate from either 50 or 60 c/s power supplies while displaying 525-line, 60 field-per-second television pictures; the tests and measurements were based upon techniques described previously. The test results show that, when operating...
Topics: receiver, receivers, picture, wobble, flicker, subjective, supply, mains, displayed, television,...
R&D Report 1964-62 : Acoustic characteristics of Maida Vale Studio 1. C.L.S. Gilford, D.K. Jones This report sketches the history of Maida Vale 1 studio from the time of acquisition by the Corporation. The major difficulty with this studio is the dip in the reverberation characteristic centred at 130 c/s which is shown to be due to vibration of the ceiling and which could be reduced by stiffening the structure. However, in view of the consideration being given to increasing the ceiling...
Topics: reverberation, ceiling, studio, frequency, stiffening, vibration, maida, absorption, woodwind,...
R&D Report 1965-10 : Transmitting aerials for the Carmarthen VHF television and VHF sound station D.W. Osborne, R.D.C. Thoday The Carmarthen relay station came into operation on 15th March 1965. It provides a television and v.h.f sound service to Carmarthen and Abergwili.
Topics: transmitting, tower, band, dipole, horizontal, gain, carmarthen, aerial, aerials, templet,...
R&D Report 1964-69 : Production of sinusoidal resolution bar patterns for inclusion in the television Test Cards 'D' and 'E'. T.N.J. Archard, D.H Rumsey, R. Sims The methods previously used for the production of sinusoidal bar patterns are first discussed and their limitations given. A modified form of one of these systems using rotating Polaroid filters and a travelling slit is fully described together with the methods used in determining the various parameters and details of processing of...
Topics: slit, density, polaroid, sinusoidal, rotating, enlarger, bar, patterns, bars, test, sinusoidal...
R&D Report 1969-30 : The contrast law of shadow mask display tubes J.R. Sanders, G.D. Judd Contrast law (gamma) measurements on typical 19 inch (49 cm) tubes are discussed. The value of gamma obtained depends on factors such as first-anode potential, and whether cathode or grid drive is used. In addition, any failure of regulation of tube supplies, video non-linearity or clamp failure, can affect the overall gamma of pictures from different types of monitor or receiver using a particular...
Topics: contrast, law, gamma, patch, drive, potentials, grid, measurements, tube, output, department...
R&D Report 1970-39 : Modulation systems for television: Theoretical comparison of noise performance, with and without pulse coding A. Brown This report compares the theoretical performance of some modulation systems which could be used for television transmission. The comparison is on the basis of the relative peak transmitted powers required for good picture quality, assuming that the performance is limited by random noise. The conclusions are summarised in graphical form.
Topics: modulation, noise, signal, analogue, coding, error, amplitude, bandwidth, probability, peak, word...
R&D Report 1971-23 : Colour film telerecording using a shadow-mask display tube J.D. Lunn The development of shadow-mask tubes with increased luminance has justified an investigation into the feasibility of using such a display in colour-film telerecording equipment. This would represent a considerable simplification over an earlier colour telerecording proposal in which a system of dichroic mirrors superimposed the displays from three separate cathode ray tubes, each carrying a single...
Topics: phosphor, display, luminance, telerecording, matrix, spectral, phosphors, film, colour, luminances,...
R&D Report 1973-03 : Radio microphones: Propagation characteristics in television studios R.D.C. Thoday This report gives the results of an investigation into propagation conditions which exist in television studios for the operation of radio microphones, and indicates the improvement in reception which can be obtained by using a diversity system.
Topics: studio, diversity, transmitter, receiving, dipole, mhz, frequency, aerials, measurements, studios,...
R&D Report 1978-19 : A digital television error-protection scheme based on waveform estimates. M.G. Croll An error-protection scheme is described which is applicable where the television signal is sampled at three-times colour subcarrier frequency. In this scheme, the otherwise redundant frequency band between 5.5 MHz and half-sampling frequency (6.65 MHz) is used for measurements to identify whether any digital errors have been introduced into the digital signal and the magnitude of such...
Topics: errors, measurement, filter, signal, digital, sample, system, error, measurement filter, digits,...
R&D Report 1977-27 : Digital television: the use of waveform estimates in error correction. C.K.P. Clarke A range of error protection methods for pcm signals is described in which redundancy inherent in the signals is used as an alternative to parity digits. Several ways of synthesising digital filters suitable for use in the protection methods are described. It is expected that, in certain circumstances, a high level of error protection could be obtained without the need for parity digits.
Topics: error, parity, estimates, estimator, signal, correction, characteristic, errors, estimators,...
R&D Report 1977-22 : An aerial diversity switch for the Channel Islands television re-broadcast link. G.H. Millard, H.M. Price The report describes an experimental diversity switch which operates during the field blanking period of the television waveform. The switch is solid state and operates very rapidly to minimize the disturbance to the television waveform. The results of an experimental period of operation are given.
Topics: diversity, signal, switch, signals, threshold, attenuator, video, receiver, ratio, aerial, video...
R&D Report 1986-02 : Colour encoding and decoding techniques for line-locked sample PAL and NTSC television signals C.K.P. Clarke For many years subcarrier-locked sampling was preferred for digital processing of composite video signals. However, the use of line-locked sampling in composite signal coders and decoders is advantageous for compatibility with studio component signals. However, the use of line-locked sampling in composite signal coders and decoders is advantageous for...
Topics: subcarrier, pal, digital, phase, signals, chrominance, signal, frequency, ntsc, sampling,...
R&D Report 1994-01 : Implementation of amplitude modulation companding using a digital signal processor. C.R.Nokes BBC Amplitude Modulation (AM) radio transmissions have for some time been using amplitude modulation companding (AMC) - a method of companding whose purpose is to reduce the costs of transmission whilst maintaining, as far as possible, the audibility of the radio service. AMC is one form of compression of AM transmissions more generally called dynamic carrier control (DCC). The...
Topics: signal, compression, modulation, amplitude, amc, bbc, carrier, dsp, enhancement, transmitter,...
R&D Report 1956-30 : Colour Television: The adaptation of the NTSC system to UK standards Part 1: The colorimetry of analysis and synthesis W.N. Sproson, J.G. Ingleton The mathematical transformations involved in specifying the ideal analysis filters for a colour scanner are described using the notation of classical matrix algebra. The colorimetric performance of an actual scanner is evaluated in terms of MacAdam's just noticeable differences. An electrical matrixing method is described...
Topics: colour, spectral, scanner, shaping, reproduced, dichroic, matrix, colours, chromaticity, filters,...
BBC Research and Development Reports
texts

eye 216

favorite 0

comment 0

R&D Report 1959-23 : Long distance overland propagation measurements at 180.4 Mc/s. J.W. Stark, K.H. Green, S.J. Ashdown, J.M. Caine, I. Rhodes This report presents the results of field strength measurements of v.h.f. transmissions on 180.4 Mc/s overland paths at distances up to 294 miles (473 km). These measurements extended over a period of approximately 3 1/2 years and have been used in the preparation of field strength/distance curves for various percentages of the overall time. The...
Topics: site, field, strength, pontop, propagation, receiving, coldfield, mursley, trees, sutton, permanent...
R&D Report 1952-02 : Some experiments on the calibration of velocity microphones at low audio frequencies by motional impedance measurements (Second Report). H.D. Harwood, D.E.L. Shorter Experiments on the low frequency calibration of ribbon type velocity microphone by electrical impedance measurements have been extended to diaphragm type microphone. One of these microphones has been calibrated by this method as a standard of frequency response in the range 40 c/s to 200 c/s and the...
Topics: frequency, ribbon, coil, velocity, motional, impedance, microphones, calibration, response,...