Monoscope

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A monoscope was a special form of cathode ray tube that was used to generate, rather than display, a video signal. Each tube was only capable of generating a single video signal, hence the name.

Essentially similar in construction to an ordinary CRT, the monoscope contained a formed metal target at the "screen" end and as the electron beam scanned the target, a varying electrical signal was produced. This signal reproduced an accurate image of the target and so could be used to produce test patterns and the like. For example, the classic Indian Head test card shown at the right was often produced using a monoscope.

[edit] See also

• Test card, the updated, colored version of monoscopes.
• Images of test cards

[edit] External links

• Monoscope tubes
• Early Television Museum
• Picture and description of the MARCONI BD665C Monoscope (UK)
• Picture and description of the RCA TK-1 Monoscope (US)
• Indian Head - "as transmitted" picture