From: jl@glen--canyon.com   
      
   On Sat, 29 Nov 2025 16:59:56 +0100, Gerhard Hoffmann    
   wrote:   
      
   >Hi,   
   >that post of mine never showed up here in the newsgroup.   
   >Nor did a retry. Did you get it as personal mail? In the sent-box   
   >it is addressed to s.e.d.   
   >   
   >Weird.   Gerhard   
      
      
   I saw it in s.e.d. and replied in the usual way. I guess you couldn't   
   see your own post for some reason.   
      
      
      
   >   
   >   
   >Am 29.11.25 um 16:40 schrieb john larkin:   
   >> On Sat, 29 Nov 2025 05:02:33 +0100, Gerhard Hoffmann    
   >> wrote:   
   >>   
   >>> Am 29.11.25 um 04:12 schrieb john larkin:   
   >>>   
   >>>>   
   >>>> We do picosecond-resolution delays with simple RCs and comparators.   
   >>>> Works fine.   
   >>>>   
   >>>> There are some programmable silicon-delay-line chips. They are   
   >>>> expensive and basically worthless.   
   >>>   
   >>> In a previous life I used a dozen or 2 of AD9500 to control the   
   >>> phase delays in a phased array to sweep the direction of the   
   >>> ultrasonic beam for scanning the inner enclosure of nuclear reactors.   
   >>>   
   >>> Worked nicely. In the lab, it was set up by a HP-85 desk top   
   >>> computer via HP-IB.   
   >>>   
   >>> 25 years later some SY89??? chips to delay a 1pps at will with   
   >>> ps resolution and CML levels. No complaints.   
   >>>   
   >>> Gerhard   
   >>   
   >> There was the MC100EP195 and the Micrel equivalent. I played with   
   >> those. The MC wasn't monotonic on delay and had a lot of jitter. Both   
   >> had bad (and unspecified) tempcos. Expensive too.   
   >>   
   >> They were switched-tap silicon delay lines.   
   >>   
   >> They might make sense at really high data rates where ramps wouldn't   
   >> work and some temperature drift would be OK.   
   >>   
   >> The AD9500 is a ramp/comparator design that's at least monotonic. It's   
   >> tempco is 7.5 ps/degc typ. It's a  Rochester part now.   
   >>   
   >>   
   >>   
   >>   
   >> John Larkin   
   >> Highland Tech Glen Canyon Design Center   
   >> Lunatic Fringe Electronics   
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)