Anything like the pnp + diode circuit shown in HP application note 301-1? Bruce
On Monday, 11 January 2016 8:00 AM, Richard (Rick) Karlquist <rich...@karlquist.com> wrote: No, it was just word of mouth within the company. Somewhere I have a piece of notebook paper on which Tom drew the circuit. We did have internal forums where papers where presented, but this was never even published internally. As with all forums, a lot of stuff happens outside the official forums in the hallways, or over lunch, etc. Ya gotta network. There was probably a great sigh of relief when I retired, and wouldn't be annoying coworkers with endless questions any more. Tom's contribution wasn't the circuit per se. I used this same basic circuit at Zeta Labs 40 years ago. I ever remember the PNP transistors we used: the Fairchild 2N5771. Those were the days... Tom's contribution was pointing out the fact that it was better than the other circuits out there, and the fact that he gave a number. It has been a never ending battle to disabuse low information designers of line receivers, comparators, and other low performance solutions. If you want to do some reading, I vaguely remember that NIST published some papers on sine to square at UFFC or PTTI. Start with Fred Walls for your search. Also remember that this circuit, as good as it is, is a poor mans substitute for the multistage zero crossing detectors discussed on this forum many times. Rick On 1/10/2016 2:24 AM, Attila Kinali wrote: > Hi Rick, > > On Sat, 9 Jan 2016 14:45:43 -0800 > "Richard (Rick) Karlquist" <rich...@karlquist.com> wrote: > >> This circuit is very similar to one that was championed by Tom >> Faulker of HP/Agilent at the now closed Spokane site. Tom >> measured the circuit at about -171 dBc/Hz. He was very knowledgeable >> about this topic, so we can believe the number. > > Is this documented anywhere publicly? I would be very interested > to read this. > > Attila Kinali > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.