Patent GB-1178330-A (GB)
Title: Electronic Synthesizer System.
Inventor: WOLFF HANNS H
IPC: H04N5/272
Filed: 1967-09-11
Abstract: 1,178,330. Teaching warfare. H. H. WOLFF. 11 Sept., 1967 [20 Sept., 1966; 27 Jan., 1967; 1 Feb., 1967], No. 41388/67. Heading F3C. [Also in Division H4] The Specification describes television apparatus for synthesizing a view, that seen through a submarine periscope for example, of a plurality of targets, of the type involving the combination of the displays from a corresponding plurality of cameras each viewing a respective target, as for example described in Specification 1,131,539 (which described apparatus can be incorporated in the present apparatus) and which is characterized by (a) the provision of scanning waveforms for the camera and the display tubes having controllable time relationships, whereby the position of a target on the display may be controlled, and (b) the provision of target video signal blanking means, whereby a target may appear on the display to disappear below the horizon. For provision (a) a line sync. pulse generator 10, Fig. 1, controls a line sweep generator 16 via a one-line period delay means 14. The output of 16 is fed to the display 20. A frame sync. pulse generator 22, controlled by generator 10 similarly produces one frame period delayed frame sweeps for the display 20. The output of generator 10 is also fed to line sweep generator 44 via a variable delay 40 whereby a delay of from zero to two line periods can be introduced. The output of generator 22 is similarly fed to frame sweep generator 60 via a zero to two frame periods delay means 54. The simulated range of the target to be scanned is set in means 150, whereby the slopes of the sweep outputs of the generators 44 and 60 it controls (i.e. the less the range, the smaller the raster in the camera tube and the larger the target image on the display tube). The sweep outputs of generators 44 and 60 are fed to the camera 48 viewing the target with line relations with respect to the display sweep signals such that for example a delay of zero to one line period in delay 40 shifts the target image to, e.g., the left-hand side of the display. So that only one image of the target appears on the display the video signals to the display are blanked except for the desired single display by the output of switch means 98 and 100. A bi-stable device 70 fed with the non- delayed A, Fig. 3 and variably delayed C line sync. pulses produces a blanking pulse G. A bi-stable device 72 similarly produces a blanking pulse F. An AND gate 102 also fed with said non-delayed and variably delayed line sync. pulses produces a blanking pulse for the case when the delay of means 40 is zero. The switch means 98 passes either blanking pulse F or G depending on whether the delay of means 40 is less or greater than one line period. The switch means 100 similarly produces UP/DOWN blanking pulses. The above described circuitry is duplicated for each camera 98A, 98B &c. For provision (b) a representation of the background, including a horizon 3, Fig. 11, is viewed by a camera 7. The representation also includes a black side strip I having a bright line 4 thereon in line with the horizon, whereby the camera produces an identifying pulse at the commencement of the line scan of the horizon. The background video signal is fed to a synthesizer 16 to produce a display on means 301. The target 5 is viewed by camera 8 and the video is fed to gate 15. A range discriminator 11 produces an output when the target range is set to be greater than the horizon range. The horizon identifying signal in the background video is gated through AND gate 13 by means of a gating pulse from line sync. pulse actuated generator 12 having a duration corresponding to the width of the strip 1. A blanking signal generator 14 produces an inhibiting signal for gate 15 on simultaneous receipt of signals from means 11 and 13, said inhibiting signal being terminated at the end of the frame by means of the frame sync. pulses. The display of that part of the target extending below the horizon is thus blanked. A complete system incorporating the above facilities and synthesizing the views of two periscopes P 1  and P 2  is shown in Fig. 6. Three targets T 1 , T 2 , T 3  are assumed. Thus for target T 1 , two models T 1a  and T 1b  are provided, each mounted on heading setting motors 1011 and 1012 and viewed by respective cameras 1013 and 1014, producing views of the respective periscopes. Each camera is provided with controllable scan systems 1013a and 1014a controlled in co-operation with setting-in means 10 and motion control computer in the manner described above for provision (a). Similar scanning systems are provided for the other two targets, and for the background. Each display may include the other periscope and scanning systems 104 and 105 are thus provided. Instead of models T 1a  and T1 b  rotating, and fixed model T 1 , Fig. 7, may be provided with the cameras mounted on rotating wheels 2004 and 2007. The target may be coated with luminescent material and illuminated by ultraviolet light.