thus the emitter of transistor 72 is connected to the collector of transistor 74 by resistor 76 the emitter of transistor 74 is grounded through resistor 78 the proper biasing of the respective bases of transistor 72 and 74 is afforded by resistors 80 82 84 85 and 86 which have the representative component values as indicated in the figure the video signal terminal 70 is connected to the base of transistor 72 by capacitor 88 and the synchronization signal is connected to terminal 90 which in turn is connected to the base of transistor 74 by capacitor 92 the video output signal is taken from the collector of transistor 72 and provided to a respective one of the three guns of a standard tv monitor not shown it will be readily apparent to those having skill in the art to which the invention is directed that if a wide black and white video signal is input to terminal 50 of the coincidence gate illustrated in fig3 that the operation of that coincidence gate as well as the video gate illustrated in fig4 will provide at the collector of transistor 72 a portion of the total bandwidth of the black and white video signal if for example the output of transistor 72 is connected to the green gun of a standard tv monitor and similar video signals from the other video gates having outputs which represent other successive portions of the black and white video signal are connected respectively to the blue and red guns of the tv monitor there will be displayed on that tv monitor a colored representation of the.