SPECIFICATION
`PATENT
`DRAWINGS ATTACHED
`
`Inventor: BERNARD MARSDEN
`
`Date offlling Complete Specification April l l, l958.
`
`Application Date April ll, l957.
`
`No. ll957,-'57.
`
`Complete Specification Published June 2!, 1961'.
`
`871238
`
`Index at aoceptance:—Class 40(3), F(2E2:3C:3K).
`International Classification: —I-II]-111.
`
`COMPLETE SPECIFICATION
`
`Television Apparatus
`We, Assoctarnn Tatzsvtsrou Lnur-ran, of
`Television House, Kingsway, London; W-C-2:
`a British Company, do hereby declare the
`invention, for which we pray that a patent
`may be granted to us, and the method by
`which it is to be performed, to be particularly
`described in and by
`the following
`state-
`ment:—
`
`the transmitting station
`at
`advertisements
`before the break in the programme.
`It is an object of the present invention to
`provide means for producing a cue or warning
`signal.
`invention provides television
`The present
`apparatus comprising means for producing a
`signal for blanking out a portion of a tele-
`vision video signal which is to form a repro-
`duced picture and means for inserting a modu-
`lated cue or warning signal into the television
`signal during the period of
`the
`blanking
`signal, so that said cue or warning signal
`appears as a visible indication in a predeter-
`mined kd position on the screen of a picture
`reproducing tube. Preferably the cue or warn-
`ing signal is arranged so that it appears adia-
`cent one corner ot
`the reproduced picture.
`With such an arrangement it is possible for
`the cue or warning signal
`to be visible on
`monitor tubes throughout the television trans-
`mitting stations and studios, whilst it will be
`situated well behind the mask on normal over-
`scan domestic television receivers and there-
`fore is not seen by the viewers of
`such
`receivers.
`
`referahly
`is
`The cue or war-nmg signal
`equency
`modulated by the output of a high
`oscillator which is inserted in the vision signal
`during the blanking
`eriod.
`One emohdiment o the invention will now
`be described with reference to the drawing
`accompanying
`the
`provisional
`specification
`which is a block diagram of a circuit arrange-
`ment according to the invention for produc-
`ing a cue signal in the form of a modulated
`patch or “dot”.
`line frequency
`Referring to the drawing,
`pulses from a synchronising pulse generator
`(not
`shown) are fed through an isolating
`amplifier
`1
`to
`a monostable oscillator 2
`through a differentiating network R1, C1 and
`a diode limiter XI. The oscillator 2 has an
`output pulse of the same polarity as its input
`
`The present invention relates to television
`apparatus and more particularly to television
`studio equipment.
`In the production and presentation of tele-
`vision programmes, the need often arises for a
`cue or warning signal which can be employed
`to give a warning to certain personnel and
`at certain points when a change or break in
`the programme is imminent. Such a signal
`is particularly desirable in cases where one
`central
`television studio is providing a pro-
`gramme which is being distributed to a
`plurality of
`transmission stations for trans-
`mission from those stations, in order to pro-
`vide the operating
`ersonnel at those trans-
`mitting stations wi
`an indication when a
`break or change is imminent in the programme
`whereby, for example,
`they may be aware
`when to commence transmitting signals from
`their own station instead of the signal received
`from the central studio.
`Thus, in commercial television programmes,
`where a common programme from a studio is
`distributed to several different
`transmitting
`stations serving dilierent areas, each of which
`inserts their own advertisements at intervals
`in the programme,
`it
`is necessary for
`the
`various stations to be advised when a break
`is about to occur in the programme, during
`which the advertisements are radiated from
`the various stations, so that no undesirable
`pauses occur between the programme and the
`advertisements during which a viewer is left
`with a blank screen on his television receiver,
`and also so that no cutting of the distributed
`programme occurs due to the insertion of the
`L "“‘”“‘*
`
`

`
`871,233
`
`trigger pulse, and means, such as a variable
`resistance, are provided for
`ad'usting the
`width of the output pulses ther
`to, which
`are arranged to be nearly one half line in
`width. These pulses from the oscillator 2 are
`applied to trigger a multivibtator 3 which can
`produce an output pulse of which the width
`can also be varied and which also has a width
`of approximately one half line. The rear edge
`of
`the pulses generated by multivibrator 3
`are used to position the cue signal on the
`right-hand side of the screen.
`Frame synchronising pulses from the syn-
`chronising pulse generator are fed through an
`isolating amplifier B and diiferentiating circuit
`R2, C2, and diode limiter K2, to a monostable
`Oscillator 9 which generates a pulse the width
`of which can be varied to determine the posi-
`tion of the cue signal in the vertical direction.
`The output of oscillator 9 is fed to multi-
`vibrator 10 which generates a pulse from the
`rear edge of the pulse generated in oscillator
`9, in order to determine the height of the cue
`signal. Negative-going output pulses from
`multivibrator 3 and positive-going output
`pulses from multivibrator 10 are gated in
`gate 4 which is a cathode-coupled mixing
`stage, and which is arranged so that its output
`consists of a train of twelve pulses during
`each vertical scan. The rear edge of each of
`these pulses is employed to trigger a multi-
`vibrator 5 which determines the width of the
`cue signal and which produces a series of
`positive-going pulses, one for each triggering
`pulse.
`If these pulses were impressed upon
`a picture monitor tube they would show as
`a white patch on the top right-hand corner of
`the picture, the size and position of this white
`patch being readily adjustable by variable con-
`trols provided in the stages 2, 3, 5, 9 and 10.
`The positive-going pulses from multivibra-
`tor S are fed through an isolating cathode
`follower 12, and a phase reverses 11 to pro-
`duce negative-going blanking pulses which are
`used in blanking our all the camera control
`equipment
`in the studio. These blanking
`pulses are arranged to have an amplitude of
`two volts with suflicient power so that
`the
`two volts can be generated across a low imped-
`ance transmission line and provide an interval
`in the picture signals generated in the studio
`during which the cue signal can be inserted.
`The positive-going pulses from multivibrator
`5 are also mixed in the cue signal modulation
`gate circuit 6 with 0.5 Mcfs oscillations pro-
`duced in oscillator 7, so that the output of
`gate 6 consists of a train of twelve pulses in
`each vertical scan period, each of the pulses
`being modulated to 100% by 0.5 Me/s oscil-
`lations. These pulses are passed through an
`amplifier 13 and a pear at its output as a
`cue dot signal whic
`is resistively mixed with
`the picture signal
`leaving the studio mixer
`and appears as a cue dot in the top right-
`hand corner of the reproduced pictures on the
`
`monitor tubes. The signal level appearing at
`the output of the amplifier 13 is such that it
`will generate 0.7 volts of cue signal on the
`low impedance output of the vision mixer.
`Stages
`11, 12 and 13 can be rendered
`operative or inoperative by means of the con-
`trol switch 17 which may be operated, for
`example, by the progrme producer. When
`the switch 17 is closed, stages 11, 12 and 13
`work normally, but when the switch is opened
`these stages are cut off by a bias signal, and
`no cue signal or blanking signal is passed to
`the output. The cue signal is, however, being
`generated permanently in stage 6, and this is
`fed to a mixer 15 where it is mixed with the
`composite synchronising signals fed from the
`synchronising pulse
`generator
`via
`ampl-
`fier
`14,
`and also the composite blanking
`signals
`fed via
`amplifier
`16,
`to deliver
`two
`preview outputs
`having
`composite
`synchronising and blanking signals mixed
`with them so that
`the cue signal can he
`previewed before it is transmitted.
`When the stages 11, 12 and 13 are made
`operative by the control switch 17, there is
`a time delay in the operation of stage 13 so
`that the cue signal does not appear on the
`outgoing waveform until after the blmzi-lg
`pulse has been established.
`This prevents
`over-loading and over-modulation of a vrhite
`background picture by the cue signal. When
`the switch is opened the negative bias supply
`is of such a magnitude that both the cue
`signal and the hlanldng signal are rapidly
`cut off.
`The cue signal generator described produces
`a cue dot in the to
`righohand corner of
`the picture, which is three microseconds wide,
`twelve lines deep, and positioned four and
`one half lines inside the vertical blanking and
`three microseconds inside the horizontal blank-
`ing. The spacing of the cue dot from the edge
`of the picture ensures that srnall random varia-
`tions in the circuits do not cause the cue
`dot to drift outside the picnuc area.
`In operation the producer actuates switch
`17 to display the cue dot signal at various
`positions in the studio and at
`transmitting
`stations receiving the programme, this signal
`being displayed at
`a predetermined time
`interval, eg. one minute hef re a bred: or
`change is to occur in the programme. The
`signal is switched oil at another predetermined
`instant, e.g.
`live seconds heiore the actual
`change in programme takes place whereby
`changes at the various stations can be accur-
`ately timed irom it.
`The one or warning signal may he used for
`the automatic control of television apparatus,
`such as a telecine machine, at one or more
`positions, by arranging that the signal con»
`trols the operation Or a photo electric cell
`which can view the cue or warning signal
`Thus, when the signal is displayed the photo
`cell may trigger a switch to switch on the 130
`
`65
`
`

`
`371
`
`lamp of the telecine machine and/or to cause
`it to run up to speed, and when the signal
`is
`switched oh,
`the photo cell operates to
`connect the telecine machine to produce the
`next programme.
`If desired various didereot
`operations controlled by the photo cell or
`plural photo cells can be respectively initiated
`by changes in the frequency or type of modu-
`lation of the one or warning signal or by
`changes in the size, shape or position of the
`signal which cause a change in the output
`from the photo cell or cells.
`It will thus be seen that with the arrange-
`ment aocording to the present invention it is
`possible to di
`lay a cue or warning signal at
`any number o remote points or transmitting
`stations receiving a
`articular programme in
`order to provide ’ crmation as to when a
`break is about to occur in a programme trans-
`mitted from a central station or studio, or
`when that programme is about to end, where-
`by it is possible immediately to start a trans-
`mission from the various transmitting stations
`open the cessation of the transmission from
`the central station, without any undesirable
`breaks or cutting of programmes on viewers
`receivers.
`Whilst a particular embodiment has been
`described it will be understood that various
`modifications may be made without departing
`from the scope of
`this
`invention. Thus
`although the cue or warning signal has been
`described as a modulated signal it may also
`be formed merely by injecting a pulse or
`series of pulses into the vision signal so as to
`produce a black or white area visible on the
`reproduced picture.
`the
`According to a further modification,
`isolating amplifiers 1 and 8 may be fed respec-
`tively with line
`and frame
`synchronising
`pulses from a synchronising separator circuit
`which separates out the synchronising pulses
`from a televinon waveform including picture
`modulation to which the cue signal is to be
`added after generation.
`In this way the cue
`signal can be inserted in a television wave-
`form at a point other than where the syn-
`chronising pulses generators are situated.
`In yet another modification of the invention
`the cue or warning signal is inserted in the
`blanking period of the television signal where
`it can be reproduced on monitor tubes, but
`so that it does not interfere with the picture
`reproduced on a normal domestic television
`receiver.
`
`WHAT WE CLAIM IS:-—
`1. Television apparatus comprising means
`for producing a signal for blanking out a por-
`tion of a teievision video signal which is to
`form a reproduced picture and means for
`inserting a modulated cue or warning signal
`
`warning signal appears as a visible indication
`in a predetermined fixed position on the screen
`of a picture reproducing tube.
`in
`2_. Apparatus as claimed in Claim 1,
`which the cue or warning signal is situated
`adjacent one corner of the reproduced picture.
`3. Apparatus as claimed in Claim 1 or 2,
`in which the cue or warning signal is modu-
`lated by the output of an oscillator.
`4. Apparatus as claimed in Claim 1, 2 or 3,
`in which the modulation is variable
`in
`frequency.
`5. Apparatus as claimed in any preceding
`claim, comprising means for generating a first
`variable width pulse at the line repetition fre-
`quency of the television waveform, means for
`generating a second variable width pulse at
`the frame repetition frequency of the tele-
`vision waveform, said variable width pulses
`serving to locate the position of the cue or
`warning signal and means for mixing the first
`and second variable width pulses to produce
`an Outp11t_ pulse train producing the cue or
`warning signal.
`in
`6. Apparatus as claimed in Claim 5,
`which the pulse train produces pulses which
`are employed to blank out the camera control
`equipment during the period of the cue or
`warning signal, and are also fed to a stage
`where they are modulated with a high fre-
`quency oscillation and mixed with the tele-
`vision picture signal.
`in
`7. Apparatus as claimed in Claim 6,
`which the cue or warning signal is switched
`into or out of
`the reproduced picture by
`means of a switch which controls the stage
`feeding the cue or warning signal to the tele-
`vision signal and also the stage feeding blank-
`ing signals to the camera control units.
`8. Apparatus as claimed in any preceding
`claim, in which means are provided for moni-
`toring the cue or warning signal, when it is
`not
`being impressed upon the
`television
`waveform.
`9. Apparatus as claimed in any preceding
`claim, in which means are provided for vary-
`ing the t_nod_ulation_ of
`the cue or warning
`signal whilst it 13 being displayed, this change
`in characteristic being employed to control
`apparatus such as a telecine machine.
`10. Television apparatus for producing a
`one or warning signal, substantially as des.
`cnbed with reference to the drawing accom-
`panying the provisional specification.
`B RON & WARREN,
`16, Kensington Square, London, W3,
`Chartered Patent Agents.
`Reformer has been directed in pursuance
`of Section 9, Sub-section (1) of the Patents
`Act, 1949 to Patent No. 633,424.
`
`

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`PROVISIONAL SPECIFICATION
`
`Television Apparatus
`
`We, Assocntrao TELEVISION LIMPIED, of
`Television I-louse, Kingsway, London, W.C.2,
`a British Company, do hereby declare this
`invention to he described in the following
`starernent:—
`
`The present invention relates to television
`apparatus and more particularly to television
`studio equipment.
`In the production and presentation of tele-
`vision programmes, the need often arises for
`a cue or warning signal which can be
`employed to give a warning to certain per-
`sonnel and at certain points when a change
`or break in the programme is imminent. Such
`a signal is particularly desirable in cases where
`one central
`television studio is providing a
`programme which is being distributed to a
`plurality of
`transmission stations for trans-
`mission from those stations, in order to pro-
`vide the operating personnel at those trans-
`mitting stations with an indication when a
`break or change is imminent in the programme
`whereby, for example,
`they may be aware
`when to commence transraitting signals from
`their own station instead of the signal received
`from the central studio.
`Thus, in commercial television programmes,
`where a common programme from a studio
`is distributed to several diiferent transmitting
`stations serving different areas, each of which
`inserts their own advertisements at intervals
`in the programme,
`it
`is necessary for the
`various stations to be advised when a break is
`about
`to occur
`in the programme, during
`which the advertisements are radiated from
`the various stations, so that no undesirable
`pauses occur between the programme and the
`advertisements during which a viewer is left
`with a blank screen on his television receiver,
`and also so that no cutting of the distributed
`programme occurs due to the insertion of the
`advertisements at
`the transmitting station
`before the break in the programme.
`It
`is an object of the present
`invention
`to provide means for producing a cue or
`warning signal.
`According to the present invention, a cue
`or warning signal is inserted into the vision
`signal so that it appears as a visible indication
`within the area of
`the reproduced picture
`formed by the vision signal. The cue or
`warning signal preferably is arranged so that
`it appears adjacent one corner of the repro-
`duced picture. With such an arranment
`it is possible for the cue or warning signal
`to be visible on monitor tubes through the
`television transmitting stations and studios,
`whilst
`it will be situated well behind the
`mask on normal overscan domestic television
`receivers and therefore is not seen by the
`viewers of such receivers.
`According to a feature of the invention, a
`
`special blanking signal is first inserted in the
`vision signal so that it occurs in the picture
`area where the cue or warning signal is to
`appear, and the cue or warning signal
`is
`inserted into the period provided by this
`blanking signal. The cue or warning signal
`referably consists of appropriate modulation,
`For example, the output of a high frequency
`oscillator which is inserted in the vision signal
`during the blanking period.
`One embodiment of the invention will now
`be described with reference to the accom-
`panying drawing which is a block diagram
`of a circuit arrangement according to the
`invention for producing a cue signal in the
`form of a modulated patch or dot.
`Referring to the drawing,
`line frequency
`pulses from the synchronising pulse generator
`(not shown) are fed through an isolating
`amplifier
`1 to a monostahle oscillator 2
`through a dilferentiating J2tEt\'.'.fDi'l{ R1, C1, and
`a limiter XI. The oscillator 2 has an output
`pulse of the same polarity as its input trigger
`pulse, and means, such as a variable resist-
`ance, are provided for adjusting the width of
`the
`output
`pulses
`therefrom, which are
`arranged to be nearly one half line in width.
`'I‘hese pulses from the oscillator 2 are applied
`to trigger a mtzltivibrator 3 which can pro-
`duce an output pulse of which the wid__th
`can also be varied and which also has a
`width of apfproximately one half line. The
`rear edge e the pulses generated by multi-
`vtbrator 3 are used to position the cue signal
`on the right-hand side of the screen.
`Frame synchronising pulses from the syn-
`chronising pulse genctator are fed through
`an isolating amp "fret 8 and diIi’erentiatir1g cir-
`cuit R2, C2, and limiter E2, to a monostalzle
`oscillator 9 which generates a pulse the width
`of which can be varied to determine the posi-
`tion of the cue signal in the vertical direction.
`The output of oscillator 9 is fed to multi-
`vibrator 10 which generates a pulse from the
`rear edge of the pulse generated in oscillator
`9,
`in_ order to determine the height of the
`cue signal. Negative-going output pulses from
`rnultivibrator
`3
`and positive~going output
`pulses from tnultivibrator 10 are gated in gate
`4 which is a cathode-cou led mixing stage,
`and which is arranged so
`at its output con-
`sists of a train of twelve pulses each vertical
`scan. The rear edge of each of these pulses
`is employed to trigger a mnltivibrator 5 which
`determines the width of the dot cue signal and
`which produces a
`train of positive-going
`pulses.
`If these pulses were impressed upon
`a picture monitor tube they would show as
`a white patch on the top right-hand corner
`Of 3316 Picturfis the size and position of this
`white patch being readily adjustable by vari-
`
`

`
`_
`
`.
`
`871,238
`
`5
`
`able controls provided in the stages 2, 3, 5,
`9 and 10.
`
`The positive-going pulses from mult.ivibra-
`tor 5 are fed through an isolating cathode
`follower 12, and a phase reverser 11 to pro-
`duce negative-going blanking pulses which are
`used in blanking out all the camera control
`equipment
`in the studio. These blanking
`pulses are arranged to have an amplitude of
`two volts with sufficient power so that
`the
`two volts can be generated across
`a
`low
`impedance transmission line and provide an
`interval in the picture signals generated in the
`studio during which the cue signal can be
`inserted.
`
`The positive-going pulses from multivibra-
`tor 5 are also mixed in the dot modulation
`gate circuit 6 with 0.5 Mc/s oscillations pro-
`duced in oscillator V7, so that the output of
`gate 6 consists of a train of twelve pulses in
`each vertical scan period, each of the pulses
`being modulated to 100% by 0.5 Mc/s oscil-
`lations. These pulses are passed through an
`amplifier 13 and appear at
`its output as a
`cue dot signal which is resistively mixed with
`the picture signal
`leaving the studio mixer
`and appears as a cue dot in the top right-
`hand corner of the reproduced pictures on
`the monitor tubes. The signal level appear-
`ing at the output of the amplifier 13 is such
`that it will generate 0.7 volts of cue signal on
`the low impedance output of the vision mixer.
`Stages 11, 12 and 13 can be rendered
`operative or inoperative by means of the con-
`trol switch 17 which may be operated, for
`example, by the programme producer. When
`the switch 17 is short-circuited, stages 11, 12
`and 13 work normally, but when the switch is
`operative these stages are cut off by a bias
`signal, and no cue signal or blanking signal
`is passed to the output. The cue signal is,
`however, being generated permanently in
`stage 6, and this is fed to a mixer 15 where
`it is mixed with the composite synchronising
`signals fed from the
`synchronising pulse
`generator via amplifier 14, and also the com-
`posite blanking signals fed via amplifier 16,
`to deiiver two preview outputs having com-
`posite synchronising and blanking signals
`mixed with them so that the cue signal can
`be previewed before it is tranmitted.
`When the stages 11, 12 and 13 are made
`operative by the control switch 17, there is a
`time delay in the operation of stage 13 so
`that the cue signal does not appear on the
`outgoing waveform until after the blanking
`pulse has been established.
`This prevents
`over-modulation of a white background pic-
`ture by the cue signal. When the switch is
`open-circuited the negative bias supply is of
`such a magnitude that both the cue signal
`and the blanking signs! are rapidly cut oil’.
`
`The cue signal generator described pro-
`duces a cue dot in the top right-hand corner
`of the picture, which is three microseconds
`wide,
`twelve line deep, and positioned four
`and one half lines inside the vertical blanking
`and three microseconds inside the horizontal
`blanking. The spacing of the cue dot from
`the edge of the picture ensures that small
`random variations in the circuits do not cause
`the cue dot to drift outside the picture area.
`In operation the producer actuates switch
`17 to display the cue dot signal at various
`positions in the studio and at
`transmitting
`stations receiving the programme, this signal
`being displayed
`at
`a predetermined time
`interval, e.g. one minute before a break or
`change is to occur in the programme. The
`signal
`is switched 0d at another predeter-
`mined instant, e.g.
`five seconds before the
`actual change in programme takes place where-
`by changes at
`the various stations can be
`accurately timed from it.
`It will thus be seen that with the arrange-
`ment according to the present invention it is
`possible to display a cue or warning signal
`to any number of remote points or transmit-
`ting stations receiving a particular programme
`in order to provide information as to when
`a break is about
`to occur in a programme
`transmitted from a central station or studio,
`or when that programme is about
`to end,
`whereby it is possible immediately to start
`a transmission from the various transmitting
`stations upon the cessation of the transmission
`from the central station, without any undesir-
`able breaks or cutting of programmes on
`viewers receivers.
`Whilst a particular embodiment has been
`described it will be mfrlerstood that various
`modifications may be made without departing
`from the scope of
`this
`invention. Thus
`although the cue or warning signal has be
`described as a modulated signal it may also
`be formed merely by injecting a pulse or
`series of pulses into the vision signal so as
`to produce a black or white area visible on
`the reproduced picture.
`the
`According to a further modification,
`isolating amplifiers 1 and 8 may be fed respec-
`tively with line and frame synchronising pulses
`from a synchronising separator circuit which
`separates out the synchronising pulses Erom a
`television waveform including picture modula-
`tion to which the cue signal is to be added
`after generation.
`In this way the cue signal
`can be inserted in a television waveform at
`a point other than where the synchronising
`pulse generators are situated.
`In yet another modification of the inven-
`tion the cue or warning signal is inserted in
`the blanking period of the television signal
`where it can be reproduced on monitor tubes,
`
`

`
`871,233
`
`the
`interfere
`but so that it does not
`picture reproduced on a normal domesttc teIe-
`vision receiver.
`
`BARON 8: WARREN,
`16, Kensington Square, London, W3,
`Chartered Patent Agents.
`
`Leamingron Spa: Printed for Her Maiesefs Stationerv Office. by the Courier Press.—I961.
`Published at The Patent Oflice. 25. Southampton. Buildings. London. ‘W.C.2, from which copies may be obtained.
`
`

`
`371233
`
`ISHEET
`
`PROV1S!ONAL SPECIFICATION
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