Patent GB-1064456-A (GB)
Title: Improvements in and relating to television effects equipment
IPC: H04N5/275
Filed: 1964-05-14
Abstract: 1,064,456. Television effects equipment. CSF-COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. May 14, 1964 [May 15, 1963], No. 20182/64. Heading H4F. Relates to apparatus for producing television effects such as " insetting " in which an image from one source is inlaid, i.e. forms an inset, in part of the area of the main television picture from another source, " progressive fade-rate " in which the size of the inset is increased until it covers the area of the television picture and " captioning " in which a sub-title " geometrical insertion " or a person " general insertion " is inserted into the television picture, the insertion being defined by its outlines. As shown, manual selector 20 has four inputs and two outputs, inputs A and B supply two conventional television picture signals, input C supplies signals obtained by scanning an extraneous object, e.g. a person, circuit Ci forming a scanning signal so that the inset may have contrast and circuit G which receives combined line and frame synchronizing signals L<SP>1</SP>, T<SP>1</SP> supplies a signal of uniform shade tint for where the inset is a sub-title. The two outputs S1 and S2 which are selected for combination by the selector 20 are passed via amplifiers 1 and 2 to the two inputs E 1  and E 2  of an electronic switch 70. The output of switch 70 is either signal S1 or S2 depending on the state of the switch and this output is fed to an output amplifier 71, the state of the switch being controlled by a switching wave fed to it over lead 72 which can adapt one or the other of two levels, e.g. " 0 " and " 1 " levels. When the " 0 " level is present the switch passes the main picture signals E 1  to its output and when the " 1 " level is present the subsidiary signals E 2  are passed on. Block 54 which receives line and frame blanking signals L and T represents an assembly of generators adapted to supply elementary signals, e.g. sawtooth signals, for the formation of signals for insetting with or without progressive change of area, a suitable combination N of signals n 1 , n 2  . . . n p  being applied through manual switch 55 to a unit 60, see later. Unit 52 which is connected to terminal C, supplies a periodical signal N<SP>1</SP> to unit 60 via manual switch 53 for " general insertion " and unit 56 which receives line and frame blanking signals L and T supplies a signal N<SP>11</SP> for " geometrical insertion." Unit 60 also has a control input U which receives in the absence of an effect a non-operating voltage U 0  and during an effect either a contrast signal voltage U or, for a progressive area change, a variable signal voltage U(t) the main picture signals from source S1 being passed on by switch 70 when the sum of N, N<SP>1</SP> or N<SP>11</SP> and either U or U(t) is less than a threshold value and the subsidiary pictures being passed on when the sum is greater than the threshold value. Unit 60 adds either N, or N<SP>1</SP> or N<SP>11</SP> to U or U 0  or U(t) and transforms the resultant total signal into a switching signal with the two possible levels " 0 " and " 1." The output of unit 60 is connected to a level converter 61 which has two outputs 62 and 63, output 62 being adapted to supply the same signal " 0 " or " 1 " as supplied at the level converter input and output 63 being adapted to supply the reversed level signal, i.e. signal " 1 " if the input signal is " 0 " and signal " 0 " if the input signal is " 1." Outputs 62 and 63 are connected to two inputs of a switching switch 64 which supplies on its output lead 72 either the signal applied to its input 62 or the signal applied to its input 63 according to its condition which is determined by a signal which is applied to its control input 73. The input U to generator unit 60 may be supplied either by a manual channel which permits all the effects to be carried out or by an automatic channel which allows only the carrying out of the progressive change-over effect. Input U is shown connected to both the output of circuit 15 of the manual channel and the output of circuit 12 of the automatic channel but at any one time it is only connected to one of the channels. The manual channel comprises a switch 3 which receives frame blanking signals T and closure of which prepares the system for manual operation supplying signals T to the input of manual switches 5, 7 and 11. When switch 3 is closed circuit 15 is connected to input U. The output of switch 11 is connected to one input of a bi-stable vibrator 13 the output of which controls the supply to circuit 15 which is a potentiometer arrangement with a manually displaceable slider. Vibrator 13 is moved into a first stable state or remains in its first state if already in that state for every input applied to its first input and is changed into its second state or remains therein for every impulse applied to its second input which is supplied by switch 5. When vibrator 13 is in its first state potentiometer circuit 15 receives a supply voltage U1 and supplies a variable output voltage between U0 and U1 depending on the position of its slider, and when it is in its second state, circuit 15 supplies a voltage U0 irrespective of the position of its slider. Switch 7 is connected as shown to the first input of a bi-stable flip-flop 67 when in its first position and to the second input of flip-flop 67 and flip-flop 13 when in its second position. When switch 7 is in its first position, flip-flop 67 adopts its its first state or remains therein, and when switch 7 is in its second position, flip-flop 67 adopts its second state or remains therein. The output of flip-flop 67 is connected to one of two equivalent inputs of a bi-stable flip-flop 68. When flip-flop 67 is in its first state its output voltage does not modify the condition in which flip-flop 68 is at that moment. When flip-flop 67 passes from its first state into its second state, flip-flop 68 changes its state, whereas the return of flip-flop 67 into its first state does not affect the state of flip-flop 68. The output of flip-flop 68 is fed to the control input 73 of the switch 64 so that there is coincidence between the state (first or second) of the flip-flop 68 and the input (first input 62 or second input 63) of the switch 64. The system is first adjusted so that switch 70 receives signal " 0 " from connection 62, that is, flip-flop 68 is caused to be in its first state and flip-flop 13 in its second state by means of switches 5 and 7, so that the transmission of the main image A takes place. To insert image B into image A the required combination of elementary signals are selected on the control board of unit 60 by means of switch 55, and switch 11 is temporarily closed causing voltage U1 instead of U0 to be applied to the control input of unit 60 thus causing unit 60 no longer to supply the signal " 0," but the effects switching signal which is a signal alternating between the levels " 0 " and " 1." The switch 64 remains in its previous condition and continues to transmit the signal applied to its input 62. This signal is therefore applied to the control input 72 of switch 70 which operates so as to introduce a fraction of the image B into the inset as determined by the settings of the effects apparatus. The inset effect is terminated by closure of the normally opened switch 5, or if full transmission of image B is required switch 7 is operated causing the signal transmitted by switch 64 to be that applied to input 63, i.e. signal " 1." For a progressively changing area the slider of the potentiometer circuit 15 is moved. To inlay into an image A, selector 20 is activated to cause the output S2 to be from G or from C1 according to whether it is desired to execute an inlay with or without contrast. The automatic channel which comprises manual switches 4 and 6, flip-flop 8, electronic switch 10 and circuit 12 which includes a flip-flop and a saw-tooth generator. such as a Miller integrator, operates so as to provide a progressive change from image A to image B occupying the whole picture area automatically. The operation is similar to that of the manual channel; the integrator output voltage rising linearly with time from the value U0 to the value U1, frame blanking pulses T, which are applied to switch 10, being applied to one of the inputs of the integrator.