> On 2024Apr 4,, at 7:22 AM, Adrian Godwin via cctalk <[email protected]> > wrote: > > This 'scope clock also uses circle generators rather than vectors to > produce well-formed characters. It mentions a Teensy controller so I don't > think it's the original made in this way - the first I heard of was too > long ago for that. But I don't know if it's an update or a separate design.
> https://scopeclock.com/ <https://scopeclock.com/> Technically, the scopeClock is generating neither curves nor vectors, it's generating pixels in an XY display - it's just that they’re of fine enough resolution and fast enough that they’re seen as a smooth-enough curve on the CRT. The MIT/Electronics-magazine and Wyle techniques are using analog electronics to generate portions of sine waves for selected phase periods and phase relation such that when applied to the XY cartesian display you get continuous portions (chords) of circles. Some digital logic gates the analog sine generators appropriately to produce the chords and line segments, with offsets, in a sequence to form characters. The scopeClock, in contrast, is using DACs in the microcontroller to generate (discrete approximations of) sine wave segments - which is to say it’s relying on the abilities of inexpensive current-day high-speed digital electronics. Thanks Paul, for pulling up the article, I recalled it as well when Rick mentioned the technique of the Wyle. I think I ran across it many years ago when sorting through stacks of Electronics magazines at our radio museum.
