[sdiy] measuring pulse width with ns accuracy...

[Bert Schiettecatte]

hi,

i didn't try it with a true oscilloscope, just spice. but I figured that
if it didn't work in spice, it probably won't work in reality either... ?

maybe I should try it in reality, but then I need a way to artificially
delay a signal by 3ns first, for my experiments.

thanks,
bert

-----Original Message-----
From: Julien Heurtebize [mailto:julien.heurtebize at tiscali.fr]
Sent: maandag 21 april 2003 1:08
To: Bert Schiettecatte
Subject: Re: [sdiy] measuring pulse width with ns accuracy...


Hi Bert !
Becareful with simulation... Do you test it with a "true" oscilloscope and a
true logic gate
like the hc32 ?
Julien.

----- Original Message -----
From: "Bert Schiettecatte" <bert.schiettecatte at esat.kuleuven.ac.be>
To: "Julien Heurtebize" <julien.heurtebize at tiscali.fr>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 21, 2003 12:56 AM
Subject: RE: [sdiy] measuring pulse width with ns accuracy...


> Hi Julien,
>
> I tried a regular OR gate (74hc32???) and it seemed to work only
> from 3ns up to 9ns (spice simulation in orcad). beyond 9ns
> the output remained high all the time, so I suspect this is because
> of the propagation delay. i'm looking at a NC7SZ32 from fairchild now,
> an OR gate with 4.1ns worst case propagation delay. Maybe this will work?
>
> I'm also trying to figure out how to delay a signal in phase by 3ns
> for example, for testing purposes.. or how to make a variable phase delay
> that works from 3ns to 10ns ... :-)
>
> thanks,
> bert
>
> -----Original Message-----
> From: Julien Heurtebize [mailto:julien.heurtebize at tiscali.fr]
> Sent: maandag 21 april 2003 0:47
> To: Bert Schiettecatte
> Subject: Re: [sdiy] measuring pulse width with ns accuracy...
>
>
> Hi Bert
> Well, in my opinion, the propagation delay in logic device is too
important
> to mesure your signal
> phase difference...
> Sorry, I don't have any ideas for the moment...
> :'(
>
> Best Regards,
> Julien.
>
> ----- Original Message -----
> From: "Bert Schiettecatte" <bert.schiettecatte at esat.kuleuven.ac.be>
> To: <synth-diy at dropmix.xs4all.nl>
> Sent: Monday, April 21, 2003 12:36 AM
> Subject: [sdiy] measuring pulse width with ns accuracy...
>
>
> > hi all,
> >
> > i'm trying to find a way to measure phase difference
> > between 2 clock signals. They have a phase difference
> > anywhere between 3ns and 10ns. I thought about OR-ing
> > these 2 signals and then using the result to charge
> > a capacitor. I could then measure the voltage across
> > the cap. Does anybody here have any idea if this will
> > work? If yes, are there certain recommendations you could
> > give me concerning what OR gate to use (I suppose the
> > one with the shortest propagation delay I can find...)
> > and what capacitor type and size?
> >
> > Thanks,
> > bert
> >
>