If you just replace, or rebuild, the oscillators in the test pattern generator with an amplitude controlled "selector" you will be able to select each character that you want. This can be done by adjusting the oscillator voltages to be just one (1) character in amplitude vertically and horisontally and then using a bias voltage to select the character that you want in X and Y positions. It will work more or less like a digital to analogue converter and you will have to make sure that it can switch reliably and fast between each character that you want. If I remember this correctly this is how it was done in the military radar screns that I serviced during the 80's, but I do not have access to the material since it was classified, so I might be wrong.
/Martin On 26 mar, 14:14, Nick <n...@desmith.net> wrote: > On Mar 26, 10:41 am, Dekatron42 <martin.forsb...@gmail.com> wrote: > > > Foundthis webpage when Googling, scroll down a bit to the monoscope > > section - with simple valve circuit diagram of test pattern > > generator!http://www.aade.com/tubepedia/1collection/tubepedia.htm > > Doing a test pattern is easy - as long as you scan at the right line > rate (couple of oscillators, bit of blanking) you get a de-facto valid > video signal - that's why they were so popular for test cards etc. - > no screen burn, no focus issues, no warm-up time (to speak of), low > technical risk etc. > > What we are talking about here is selecting glyphs from the grid of a > NON-TESTCARD monoscope, i.e. an alphanumeric one. This is a much more > complex problem. > > Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
