<Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> As was the case with black - and - white television, an electronic means of scanning would be superior to the mechanical systems like Baird's . The obvious solution on the broadcast end would be to use three conventional Iconoscopes with colored filters in front of them to produce an RGB signal . Using three separate tubes each looking at the same scene would produce slight differences in parallax between the frames, so in practice a single lens was used with a mirror or prism system to separate the colors for the separate tubes . Each tube captured a complete frame and the signal was converted into radio in a fashion essentially identical to the existing black - and - white systems . </P> <P> The problem with this approach was there was no simple way to recombine them on the receiver end . If each image was sent at the same time on different frequencies, the images would have to be "stacked" somehow on the display, in real time . The simplest way to do this would be to reverse the system used in the camera; arrange three separate black - and - white displays behind colored filters and then optically combine their images using mirrors or prisms onto a suitable screen, like frosted glass . RCA built just such a system in order to present the first electronically scanned color television demonstration on February 5, 1940, privately shown to members of the US Federal Communications Commission at the RCA plant in Camden, New Jersey . This system, however, suffered from the twin problems of costing at least three times as much as a conventional black - and - white set, as well as having very dim pictures, the result of the fairly low illumination given off by tubes of the era . Projection systems of this sort would become common decades later, however, with improvements in technology . </P> <P> Another solution would be to use a single screen, but break it up into a pattern of closely spaced colored phosphors instead of an even coating of white . Three receivers would be used, each sending its output to a separate electron gun, aimed at its colored phosphor . Although obvious, this solution was not practical . The electron guns used in monochrome televisions had limited resolution, and if one wanted to retain the resolution of existing monochrome displays, the guns would have to focus on individual dots three times smaller . This was beyond the state of the art at the time . </P>

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