R&D Report 1965-51 : Servo-controlled, one-line delay for 625-line television signals. S.M. Edwardson, A.D. Stalley, G.C. Wilkinson This report describes apparatus designed to delay a mains-locked 625-line television signal by a period equal to the duration of one television scanning line. The equipment was designed primarily for use in a line-store standards converter but has other applications in television engineering. A fused-quartz ultrasonic delay is employed as the main delay element...
Topics: delay, output, signal, gain, frequency, television, input, amplifier, variable, quartz, television...
R&D Report 1966-38 : A phase-corrected video "notch" filter R.E. Davies, G. Edmondson Video "notch" filters are used in television apparatus to suppress unwanted spectral components in the video-frequency band; an important application is the suppressions of signal components at the colour-subcarrier frequency in the luminance channel of colour television equipment. However, the presence of a notch filter results in "ringing" whenever transients are present and...
Topics: filter, notch, phase, circuit, frequencies, bandwidth, components, frequency, signal, delay,...
R&D Report 1965-05 : Surface-wave feeders for U.H.F. site tests D.E. Susans This report describes experimental surface-wave feeders and launching horns for use with balloons for u.h.f. site tests. The general problems associated with design of this type of transmissions system are discussed together with the results on some practical feeders and horns.
Topics: horn, feeder, cable, dielectric, conductor, loss, feeders, balloon, power, conical, launching horn,...
R&D Report 1964-78 : Transmitting aerials for the Hereford VHF television and VHF sound station D.W. Osborne A brief summary of the installation of Hereford Relay Station.
Topics: aerials, transmitting, horizontal, band, templet, gain, hereford, aerial, radiation, receiving,...
R&D Report 1968-31 : An active deflector suitable for U.H.F. television transmissions D.E. Susans, D.G. Beadle This report describes equipment which has been developed to appraise active deflector transmissions for filling in pockets of low field strength within the main service area of UHF transmitters. The equipment is portable and can be readily aligned on any channel within Bands IV and V. Details of the performance are given and other uses of the basic principle are discussed.
Topics: amplifier, output, amplifiers, input, filter, transistor, deflector, power, coupler, active, peak...
R&D Report 1968-23 : Construction of multilayer dielectric filters M.K.E. Smith A vacuum coating plant was installed at Research Department in September 1965 and has been used for the construction of multilayer dielectric filters. Techniques developed so far for evaporating materials and monitoring the thickness of the layers are described. The characteristics of some filters constructed are shown in comparison with the theoretical characteristics.
Topics: filters, filter, transmission, dielectric, refractive, multilayer, wavelength, monitoring, layers,...
R&D Report 1968-24 : Scanning distortions and misregistration in the Peto-Scott 3-plumbicon colour camera G.M. Le Couteur An investigation was undertaken into the types of geometrical distortion encountered in a large number of scanning yokes used in the Philips/Peto-Scott 3-plumbicon colour cameras. The relative geometric distortions, or misregistrations, between yokes were also investigated, together with the feasibility of using these measurements to select groups of 3 yokes with similar...
Topics: vertical, yokes, horizontal, errors, measurement, skew, yoke, misregistration, lens, distortion,...
R&D Report 1964-16 : UHF amplifier and distribution unit D.E. Susans This report describes a simple single-transistor u.h.f. amplifier suitable for use either as a low noise pre-amplifier for a receiver or as a mast-head amplifier remote from the receiver. The amplifier, with a gain of 12 dB, can be made for use at any single Band IV and V television channel. A bridge distribution unit is also described which enables the output of the amplifier or other u.h.f. source to be split into four...
Topics: amplifier, distribution, input, bridge, transistor, unit, output, circuit, outlets, cable,...
R&D Report 1964-21 : Transmitting aerials for the Enniskillen VHF television and VHF sound station D.W. Osborne A brief summary of installation of Enniskillen relay station.
Topics: aerial, enniskillen, gain, feeders, aerials, band, tower, templet, sound, horizontal, effective...
R&D Report 1967-25 : H.F. bridge receiver / oscillator, Mark 3 R.V. Harvey, A. Brown, P.C.J. Hill This report describes a unit in which an oscillator, covering the frequency range 3.5 to 30 MHz, is mechanically ganged to a receiver covering the same range. This unit is intended to be used in association with an admittance bridge for measurements on aerial and feeder systems at high-frequency transmitting stations.
Topics: oscillator, receiver, frequency, mhz, circuit, output, wideband, amplifier, input, selectivity,...
R&D Report 1964-80 : New Band I transmitting aerial for the Sutton Coldfield television station. G.H. Millard, M.W. Greenway A brief summary of the installation of Sutton Coldfield Relay Station.
Topics: aerial, scattering, mast, dipoles, band, coldfield, transmitting, templet, horizontal, radiation,...
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...
R&D Report 1966-42 : The C.B.S. 'Audimax II RZ' automatic control amplifier. D.W. Stebbings The "Audimax II RZ" is an automatic gain control amplifier produced by the Columbia Broadcasting System in the U.S.A. It is intended to reduce the need for manual control of signal levels at a studio and also to raise the mean signal level as far as is possible without introducing impairments to the technical or aesthetic quality programme. The device is effective on many types of programme...
Topics: amplifier, gain, dbm, level, programme, output, control, input, characteristic, signal, input...
R&D Report 1966-26 : Tristimulus spot colorimeter. H.A.S. Philippart The report describes a photoelectric tristimulus spot colorimeter which measures the three stimuli X, Y, Z, as specified by the C.I.F. (Commission Internationale de l'Eclairage) standard observer, and thus permits simple calculation of the x and y trichromatic coefficients (chromaticity co-ordinates). In addition to the usual measurements of the colours of materials, the instrument permits measurements of the colours...
Topics: filters, instrument, tristimulus, colour, wavelength, filter, spectral, colorimeter,...
R&D Report 1964-76 : Photometric lens-aperture measuring equipment H.A.S. Philippart A photometric lens-aperture measuring set is described by means of which lenses can be calibrated in terms of the 'T' number. The apparatus can deal with lenses whose focal lengths lie within the range 1 in. to 40 in. (2.54 cm to 1.02 m). The system used is similar to that used by M.G. Townsley and consists of a comparison method in which two beams of light are used, one to provide light for the lens under...
Topics: lens, aperture, focal, calibration, beam, calibrated, lenses, wedge, photometric, light,...
R&D Report 1968-28 : A digital terrain coder for transferring map data onto paper tape D.E. Susans A description is given of equipment used to prepare the main input data for predicting the service area of UHF transmitters by computer. Information on contour height and other topographical features as a function of bearing and distance from the transmitter, obtained from Ordnance Survey maps, is coded and punched onto a paper tape. This can be done directly by an operator who is well versed...
Topics: height, cursor, counter, distance, data, motor, punched, punch, radial, sequence, punch sequence,...
R&D Report 1966-71 : The RAI limiter D.W. Stebbings Tests have been carried out on a sound signal limiter designed R.A.I. the Italian Radio and Television Service. In this device, a gain control system having an exceptionally short attack time, together with a signal delay network introduced ahead of the variable gain element, combine to reduce any transient overshoot of the output signal amplitude to very small proportions. Moreover, in an attempt to minimise the unaesthetic effects of...
Topics: limiter, gain, signal, output, distortion, dbm, recovery, characteristic, bias, input, attack...
R&D Report 1965-47 : The C.B.S 'Volumax' limiter D.W. Stebbings The 'Volumax' limiter is an automatic gain regulating device for controlling the programme input to a transmitter; it is claimed that it will maintain a high average programme level while preventing overmodulation. The limiter has a slower attack time and a faster recovery time than the corresponding Corporation equipment, and relies on a built-in peak clipper to prevent momentary overmodulation. The performance of the...
Topics: limiter, clipper, gain, characteristic, clipping, output, distortion, signal, peak, reduction,...
R&D Report 1968-52 : A frequency-dependent compandor system for high-quality sound signal distribution D.E.L. Shorter, W.I. Manson Compandors of the type used in telephony for the improvement of signal-to-noise ratio are unsatisfactory for high-quality sound circuits because of the objectionable effect produced by programme-modulated noise. In the case of 'white' noise, this difficulty can be largely overcome by splitting the audio-frequency range into two parts and applying the compandor...
Topics: signal, gain, pilot, tone, frequency, system, limiter, compandor, delay, programme, sending...
R&D Report 1968-54 : Bath 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, transmitting, band, mhz, receiving, installation, pid, horizontal, transmitter, radiation,...
R&D Report 1964-55 : Ultrasonic delay lines for millisecond delays S.N. Watson, R.D.A. Mathers A one day visit to the Corning Glass Company's works at Bradford, Pennsylvania, was paid by the writers in order to discuss the performance of Corning glass delay lines. This report summarises that day's discussions.
Topics: delay, specification, corning, ultrasonic, delays, input, comments, comings, secondaries, facet,...
R&D Report 1968-16 : Llanidloes 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: band, aerial, transmitting, etn, radiation, transmitter, receiving, horizontal, arrangement, relay,...
R&D Report 1965-34 : The Neumann KM64 microphone H.D. Harwood This report describes tests carried out on the latest capacitor microphone, type KM64, manufactured by Messrs, Neumann of Berlin. The microphone has a cardioid directional characteristic and is of the end-fire type design. Measurements have been made of the frequency characteristics for sound incident at various angles; the degree of interference from wind, with and without a windshield, and from magnetic fields has also been...
Topics: microphone, noise, frequency, characteristics, measurements, magnetic, type, neumann, sensitivity,...
R&D Report 1967-12 : Equipment for the statistical analysis of programme meter deflexions J.R. Chew, A.A. Harris The apparatus described examines the fluctuating deflections of a programme meter by arranging that an image of the moving pointer falls, according to its position, upon different members of a suitable array of photo cells. The positions of the cells can be set relative to the image of the scale of the instrument to record data according to the scale region of greatest interest....
Topics: meter, programme, analysis, logic, pointer, statistical, output, deflexions, bistable, data,...
R&D Report 1966-43 : Simple application to broadcasting of the results of subjective tests. R.D.A. Maurice The report discusses some different scales of criteria suitable for subjective tests for broadcasting applications and mentions a method of using the statistical results of subjective tests that may make maximum use of them aid management decision making.
Topics: subjective, impairment, grade, assessments, gaussian, statistical, tests, broadcasting, percentage,...
R&D Report 1968-40 : A set of phosphors for use in a colour telerecording display E.W. Taylor, G.D. Judd The spectral and actinic characteristics of three phosphors (red, green and blue) for use in a colour-telerecording display are described. Absorption-type filters are specified for shaping their emission spectra.
Topics: phosphors, phosphor, spectral, actinic, exposure, display, telerecording, cathode, filters,...
R&D Report 1967-46 : An analogue multiplier for correlation R.J.J. Roach This report describes an analogue multiplier using a variable area method in which a repetitive waveform is produced with a mark-to-space ratio dependent upon one multiplicand and an amplitude dependent upon the other. The resulting waveform is integrated by a resistance-capacity network and the DC voltage so produced is fed to a diode chopper which is switched by a 1.5 kHz square-wave. The 1.5 kHz waveform is...
Topics: output, input, multiplier, waveform, analogue, voltage, volts, khz, ratio, multivibrator, square...
R&D Report 1964-26 : Service areas of the Llandrindod Wells television and VHF sound transmitters H.T. Madoc-Jones, J.A. Carter A brief summary of the installation of Llandrindod Wells Relay Station.
Topics: wells, transmitters, llandrindod, contours, exceeded, field, television, strength, aerial, sound,...
R&D Report 1966-09 : Resolving the conflict between amplitude and group delay requirements for certain types of low-pass filter. J.W. Head In application to television, if a low-pass filter is required and the tolerances on variation of group delay and amplitude in the effective pass band are not stringent but simplicity is important, priority should be given to meeting, the group-delay requirements. This is discussed in detail for cases in which the insertion transfer is the reciprocal of...
Topics: amplitude, gouriet, butterworth, transfer, group, compromise, function, delay, filter, unity,...
R&D Report 1967-32 : A review of vertical aperture correctors W. Wharton, S.M. Edwardson A vertical aperture corrector for television can be constructed in two basic forms. The first of these uses two delays, each of one television line period, whilst the second uses only one such delay and the signal re-circulates, passing more than once through the delay path. The report compares the two basic forms and discusses their relative advantages and disadvantages in the light of practical...
Topics: vertical, aperture, corrector, correction, blanking, correctors, delay, signal, output, picture,...
R&D Report 1964-63 : Time variations of UHF and VHF signals at short distances J.W. Stark Field strength measurements of transmissions from Crystal Palace in Channels 1, 34 and 44 were carried out at distance of 11 miles (17.7. km) and 31.7. miles (51.0 km). The results show that the Channel 44 median signals are 3 to 4 dB lower in summer than in winter, presumably due to absorption by foliage. There is no corresponding effect on Channel 1 signal levels. During abnormal propagation...
Topics: baddow, kingswood, channel, field, transmitting, measurements, fading, median, receiving, great,...
R&D Report 1964-59 : Transmitting aerial for the Canterbury VHF television station. R.D.C. Thoday A brief summary of the installation of Canterbury Relay Station.
Topics: aerial, canterbury, yagi, transmitting, carrier, tower, oriented, aerials, templet, technological,...
R&D Report 1966-04 : Acoustic tests on the Walker Memorial Hall, Birmingham. C.L.S. Gilford, T.J.B. Smith Acoustic tests carried out before and after modifications to the Walker Memorial Hall, Birmingham are described. Floor resonances which caused unacceptable musical quality satisfactorily removed.
Topics: reverberation, measurements, floor, studio, decay, accelerometer, cubicle, acoustic, resonances,...
R&D Report 1965-27 : Digital coding equipment for recording field-strength measurements D.E. Susans This report describes a voltage coder and tape perforator which samples the d.c. output from one or more field-strength recording receivers at regular intervals and records the values by means of a 5-unit binary code, on a paper tape which can subsequently be fed into a computer for analysis.
Topics: input, unit, counter, perforator, coder, binary, voltage, amplifier, transistor, trl, technological...
R&D Report 1964-38 : Transistorized EHT supply for multiplier photo-cells H.A.S. Philippart Multiplier photo-cells normally require a high tension supply of the order of 1000 volts. This supply is usually obtained from the electricity supply mains by means of conventional rectifiers and stabilizing circuits. Mains surges can still be detected however unless more complex and bulky equipment is used. In the case of a fixed installation this is not a great importance but when portability and...
Topics: output, voltage, transistorized, converter, zener, performance, multiplier, supply, technological,...
R&D Report 1964-77 : Simple drop-out compensator for video tape recorders W.K.E. Geddes A brief description is given of a simple device that considerably reduces the subjective impairment produced by 'drop-out' in video tape recording. Subjective tests are described whose results indicate the degree of improvement to be expected from use of such a device.
Topics: compensator, video, signal, impairment, subjective, luminance, experimental, duration, compensated,...
R&D Report 1964-54 : Appraisal of the RCA four-tube colour television camera Type TK 42 S.N. Watson, R.D.A. Maurice, A.R. Stanley The authors of this report spent three days in Camden, New Jersey, in order to be able to make measurements and subjective appraisals of the performance of the R.C.A. four-tube colour camera type TK 42. The results achieved are recorded in what follows.
Topics: camera, luminance, tube, chrominance, orthicon, aperture, picture, colour, image, average, picture...
R&D Report 1964-17 : Transmitting aerial for the Holyhead VHF television station D.W. Osborne A brief summary of installation of Holyhead relay station.
Topics: aerial, transmitting, horizontal, tower, height, technological, channel, holyhead, dipoles, dipole,...
R&D Report 1964-09 : Service areas of the Ashkirk television and VHF sound transmitters H.T. Madoc-Jones, J.A. Carter A brief summary of the installation of Ashkirk relay station.
Topics: ashkirk, transmitters, field, aerial, exceeded, sound, strength, television, tiers, receiving,...
R&D Report 1966-65 : New equipment for the statistical analysis of sound programme levels J.R. Chew, R.L. Deane The report describes apparatus for the statistical analysis of programme level, fluctuations. The equipment, which is transistorized and self-contained, can be used either for counting and classifying programme peaks or for analysing the levels on a percentage time basis, functions previously performed by two separate and now obsolete devices. The new equipment is free from some...
Topics: voltage, signal, peak, level, trough, programme, pulse, circuit, transistors, counting, level...
R&D Report 1964-35 : Service areas of the Holme Moss television and VHF sound transmitters J.H. Causebrook, J.A. Carter A brief summary of the installation of Holme Moss Relay Station
Topics: field, vision, sound, strength, medi, median, holme, transmitters, town, moss, moss television,...
R&D Report 1967-44 : Kilkeel VHF relay station: Summary of installation R.D.C. Thoday A brief data sheet detailing frequencies, equipment installed, radiation characteristics etc, including graphs of radiation patterns.
Topics: band, aerial, transmitting, horizontal, mhz, installation, etn, kilkeel, transmitter, radiation,...
R&D Report 1964-22 : Transmitting aerials for the Haverfordwest VHF television and VHF sound station. D.W. Osborne A brief summary of installation of Haverfordwest relay station.
Topics: aerial, band, tiers, horizontal, gain, aerials, polarization, dipoles, corresponds, theoretical,...
R&D Report 1966-70 : UHF transmitting aerial for the Pontop Pike television station G.H. Millard A u.h.f. transmitting aerial for the Durham area has been built as a topmast on the existing 133 m (438 ft.) mast at Pontop Pike. Space for this aerial was provided by rebuilding the Band I aerial on the support column of the mastl. The new aerial started test transmissions on 22nd October, 1966 and came into full service on 5th November, 1966.
Topics: aerial, channel, panels, transmitter, vision, feeder, transmitting, radiation, transmitters,...
R&D Report 1968-34 : Lochgilphead 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 a graph of horizontal radiation.
Topics: band, aerial, lochgilphead, horizontal, installation, radiation, pid, transmitting, bbc,...
R&D Report 1964-14 : Transmitting aerial for the Eastbourne VHF television station D.W. Osborne A brief summary of installation of Eastbourne relay station.
Topics: aerial, transmitting, tower, feeders, height, technological, channel, eastbourne, templet, gain,...
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,...
R&D Report 1967-18 : The use of flexible couplings to reduce the transmission of vibrations through water pipes D.K. Jones In studio centres now being built in which a combination of hot-water radiators and simple ventilation systems is used instead of complete air conditioning, vibrations transmitted along the hot-water pipe system into the studios may constitute a source of acoustic noise. This report describes a series of experiments which were undertaken to determine the reduction in...
Topics: couplings, coupling, flexible, transverse, pipe, radiated, vibration, pipes, transmission,...
R&D Report 1967-41 : Buzz on sound in 625-line television reception G.J. Phillips, J.D. Lunn This report is an attempt to put the various aspects of the buzz-on-sound problem in perspective. The principal subject of discussion is the effect of non-linearities in a receiver on the sub-harmonics of 6 MHz in the video information. Other possible causes of buzz are mentioned, and some conclusions are drawn regarding receiver design; in particular, the use of two separate diode detectors for...
Topics: buzz, mhz, sound, receivers, frequency, burble, receiver, carrier, video, vision, strong buzz,...
R&D Report 1965-07 : Response of a peak rectifier to a suddenly applied ac signal J.W. Head The charge time-constant of a peak rectifier is commonly specified in terms of the rate of rise of voltage with time when a sinusoidal signal is suddenly applied. An expression for rise time is derived, particularly for the case in which the time of one cycle of a.c. is small compared with the charge time-constant of the rectified system; the time then taken for the rectified voltage to reach any...
Topics: voltage, rectifier, cot, equation, applied, signal, input, cycle, half, nth, cos cot, small...
