# laser pulse vs trigger pulse in oscilloscope

Started by October 25, 2010
```On Oct 25, 7:26=A0pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
> On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>
>
>
> > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>
> > > This was posted in sci.physics.research.
>
> > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>
> > > > Dear Friends
> > > > =A0I want to do some experiment in pulsed laser. I attached output =
of a
> > > > laser to one channel of oscilloscope via photodiode to see the shap=
e
> > > > of the pulse. then I attach the =A0one output of =A0RF trigger of t=
he
> > > > qswitch to the other channel of the oscilloscope =A0to see the =A0s=
quare
> > > > shape pulse =A0of the =A0Rf trigger till now everything is ok I can=
see
> > > > both pulses. But I can't interpret the relation between two pulses.=
To
> > > > my knowledge when we have RF we shouldn't have any laser pulse and
> > > > when the RF vanishes we should have laser pulse . it means =A0 that=
when
> > > > we compare two pulses =A0in the oscilloscope as soon as the square =
shape
> > > > trigger pulse vanishes the laser pulse must =A0be appear =A0but it =
appears
> > > > later in the train of the pulse . what is the problem ?
> > > > Is the measuring equipment is poor or it has theoretical problem.
> > > > Thanks in advance
>
> > > To start I'm reposting that to
> > > sci . electronics . design
> > > Regards
> > > Ken
> > > PS: One guys there is really smart, I don't know about the rest,
> > > of the others.
>
> > Presumably the Q-switch is being driven by periodic signal - you get a
> > burst of RF, then no RF, then another burst of RF in a pattern that
> > repeats itself exactly.
>
> > The claim is that the laser pulse should appear when the RF has been
> > switched off.
>
> > If the period being displayed on the oscilliscope screen is long
> > enough to include two or more bursts of RF on one channel, the laser
> > pulse being displayed from the other channel will show up between the
> > two bursts of RF - the precise time relationship depends on how the Q-
> > switch works.
>
> > This doesn't sound like the sort of question that needs anybody really
> > system and the Q-switch, there might be more that could be said by
> > someone sufficiently well-informed (though not necessarily all that
> > smart).
> > Bill Sloman, Nijmegen
>
> I single handidly invented the optical world! (had some help though).
> Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km,
> watch the return on the scope, reckon dispersion, that's how the
> pulse base spread a bit, and from that 'ballpark' a max fequency,
> for that particular fibre media.
> Next thing we had to do was join and tap the fibre, cost was no
> object, except my pay.
> Obviously, I'm a bit rusty, so I posted this for those who might
> understand what the fella (OP from spr) is driving at.

Bully for you. Why did we need to know that?

--
Bill Sloman, Nijmegen

```
```On Oct 26, 1:36=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> On Mon, 25 Oct 2010 16:22:22 -0700 (PDT), Bill Sloman
>
> <bill.slo...@ieee.org> wrote:
> >On Oct 25, 7:23=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> >> On Mon, 25 Oct 2010 09:42:54 -0700 (PDT), Bill Sloman
>
> >> <bill.slo...@ieee.org> wrote:
> >> >On Oct 25, 5:36=A0pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
> >> >> This was posted in sci.physics.research.
>
> >> >> On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>
> >> >> > Dear Friends
> >> >> > =A0I want to do some experiment in pulsed laser. I attached outpu=
t of a
> >> >> > laser to one channel of oscilloscope via photodiode to see the sh=
ape
> >> >> > of the pulse. then I attach the =A0one output of =A0RF trigger of=
the
> >> >> > qswitch to the other channel of the oscilloscope =A0to see the =
=A0square
> >> >> > shape pulse =A0of the =A0Rf trigger till now everything is ok I c=
an see
> >> >> > both pulses. But I can't interpret the relation between two pulse=
s. To
> >> >> > my knowledge when we have RF we shouldn't have any laser pulse an=
d
> >> >> > when the RF vanishes we should have laser pulse . it means =A0 th=
at when
> >> >> > we compare two pulses =A0in the oscilloscope as soon as the squar=
e shape
> >> >> > trigger pulse vanishes the laser pulse must =A0be appear =A0but i=
t appears
> >> >> > later in the train of the pulse . what is the problem ?
> >> >> > Is the measuring equipment is poor or it has theoretical problem.
> >> >> > Thanks in advance
>
> >> >> To start I'm reposting that to
> >> >> sci . electronics . design
> >> >> Regards
> >> >> Ken
> >> >> PS: One guys there is really smart, I don't know about the rest,
> >> >> of the others.
>
> >> >Presumably the Q-switch is being driven by periodic signal - you get =
a
> >> >burst of RF, then no RF, then another burst of RF in a pattern that
> >> >repeats itself exactly.
>
> >> >The claim is that the laser pulse should appear when the RF has been
> >> >switched off.
>
> >> No, the claim is that the laser pulse should appear when the trailing
> >> edge of the Q-switch trigger happens.
>
> >Would you care to specify the repetition rate of the RF pulses? And
> >the gap between the "disappearance" =A0of the RF pulse and the
> >appearance of the laser pulse? The only time I had much to do with an
> >argon ion laser, the natural period of the laser - set by the cavity
> >length - was 80MHz, so the pulses would have appeared every 12.5nsec,
> >but there was a Q-switch which allowed you to pick out single pulses
> >from time to time. The 12.5 nsec corresponds to the time it takes for
> >light to travel 12.5 feet, and you can can get that kind of signal
> >propagation around a lash-up without trying very hard.
>
> What does all that crap have to do with anything?
>
> The man stated that he could see both the square trigger pulse from
> the Q-switch and the pulse from the photodiode, but that the pulse
> from the photodiode was appearing, not at the end of the trigger
> pulse, as expected, but later on.
>
> He then asked if anyone could explain why that was happening.
>
> You then posted the following:
>
> >> >If the period being displayed on the oscilliscope screen is long
> >> >enough to include two or more bursts of RF on one channel, the laser
> >> >pulse being displayed from the other channel will show up between the
> >> >two bursts of RF - the precise time relationship depends on how the Q=
-
> >> >switch works.
>
> which indicates that you didn't understand that he had already stated
> that he could see both pulses and was asking for the reason why they
> weren't temporally aligned in the way he expected.

reconstructing his observations in terms that suited the dieas that I
was trying to get across.

> >> He has no trouble seeing both signals, his concern is with the laser
> >> pulse showing up later than it's supposed to.
>
> >Since he hasn't put any numbers on his expectations, he obviously
> >hasn't started thinking about what is going on. Since you haven't
> >either, your "later than it is supposed to" represents a comparable
> >failure to engage what brain you've got.
>
> Since the premise is that the laser pulse should start _immediately_
> following the termination of the trigger pulse, there are no numbers
> required since the timing is inherent in the statement.

Don't be stupid. Nothing starts "immediately". there are always
propagation delays around the system, and if you get them wrong the
laser pulse can show up on the screen before the end of the RF pulse
which was supposed to have triggered it - but only if you've got a
looong cable frpm the RF pulse gnerator to the scope

> Since you don't aseem to be able to understand a string of words all
> that well, here's a picture:
>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 -->|<--dT =3D 0
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0____
> TRIG____________| =A0 =A0|_____________________
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 _
> PD___________________| |___________________
>
> As usual, when you're wrong, instead of just admitting it and getting
> on with your life you thrash around and hurl unwarranted invective in
> a vain attempt to muddy the water and move the finger that's pointing
> at you to point at something else. =A0Cheater.

Don't be silly. You've invested a great deal in the idea that
"immediately" means a picosecond precise alignement, when if you took
thirty seconds to think about what you were you'd realise that this is
nonsense.

> >> >This doesn't sound like the sort of question that needs anybody reall=
y
> >> >smart to answer it.
>
> Perhaps not, but since you couldn't answer it it would have to be
> someone smarter than you.

That may be your opinion. As usual, it hasn't got mucy to do with
reality.

> >> >If the OP had given some detail about the laser
> >> >system and the Q-switch, there might be more that could be said by
> >> >someone sufficiently well-informed (though not necessarily all that
> >> >smart).
>
> Yeah, right, blame it on the OP.

Who else?

> >> First, one must learn to understand what he reads.
>
> >Sure. You've obviously failed that first step, since you haven't
> >noticed that there wasn't a lot to understand.
>
> Since you didn't even get what little there was, it seems you've
> hoisted yourself with your own petard in a deliciously ironic way.

Dram on, nitwit.

> Or as Shakespeare had Hamlet say:
>
> "For 'tis the sport to have the enginer / Hoist with his owne
> petar" -- Hamlet III iv.

The real irony is that you won't have noticed that _your_ little hand-
cannon blew up in _your_ face, as Joe Legris has - very kindly - taken
the trouble to point out.

--
Bill Sloman, Nijmegen

```
```On Tue, 26 Oct 2010 06:48:35 -0700 (PDT), "J.A. Legris"
<jalegris@sympatico.ca> wrote:

>On Oct 26, 7:36&#2013266080;am, John Fields <jfie...@austininstruments.com> wrote:
>
>> Since you didn't even get what little there was, it seems you've
>> hoisted yourself with your own petard in a deliciously ironic way.
>>
>> Or as Shakespeare had Hamlet say:
>>
>> "For 'tis the sport to have the enginer / Hoist with his owne
>> petar" -- Hamlet III iv.
>>
>
>There's no greater irony here than the spectacle of you, an insecure
>self-conscious low-brow, desperately trying to acquire an ounce of
>self-respect through repeated unprovoked attacks on Sloman.

---
If you think they're unprovoked, then you're cut from the same cloth
he is and no doubt share the same delusions.
---

>It's not working.

---
Just for grins, let's say I _was_ trying to acquire some self respect
that way.  How would you know it wasn't working?

In fact, if I _didn't_ catch his errors and feed them back to him, I'd
feel remiss and lacking in self-respect.
---

>Maybe you should go back to calling yourself "Professional
>Circuit Designer" or even "El Presidente", but then those didn't work
>either did they?

---
Times change, and I see now that you've been in my shit for a long
while, yes?

Either that or you've been checking my posting history from way back
when.

Why, I wonder?
---

>Quoting Shakespeare is just another bad idea.

---
For you, maybe, but I find his stuff pretty good, and often apt, so I
can't imagine why you'd foist your limitations on me.
---

>You may achieve more success if you simply avoid trusting your
>instincts and, like George Constanza, just do the opposite!

---
Well, if I ever get ready for a canned sit-com life, which is where
you seem to be coming from, you'll be the first one I call for advice
on which character to play.

In the meantime, Newman, try to get back on topic and mind your own

---
JF
```
```On Tue, 26 Oct 2010 07:52:16 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

>On Oct 26, 1:36&#2013266080;pm, John Fields <jfie...@austininstruments.com> wrote:
>> On Mon, 25 Oct 2010 16:22:22 -0700 (PDT), Bill Sloman
>>
>> <bill.slo...@ieee.org> wrote:
>> >On Oct 25, 7:23&#2013266080;pm, John Fields <jfie...@austininstruments.com> wrote:
>> >> On Mon, 25 Oct 2010 09:42:54 -0700 (PDT), Bill Sloman
>>
>> >> <bill.slo...@ieee.org> wrote:
>> >> >On Oct 25, 5:36&#2013266080;pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>> >> >> This was posted in sci.physics.research.
>>
>> >> >> On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>>
>> >> >> > Dear Friends
>> >> >> > &#2013266080;I want to do some experiment in pulsed laser. I attached output of a
>> >> >> > laser to one channel of oscilloscope via photodiode to see the shape
>> >> >> > of the pulse. then I attach the &#2013266080;one output of &#2013266080;RF trigger of the
>> >> >> > qswitch to the other channel of the oscilloscope &#2013266080;to see the &#2013266080;square
>> >> >> > shape pulse &#2013266080;of the &#2013266080;Rf trigger till now everything is ok I can see
>> >> >> > both pulses. But I can't interpret the relation between two pulses. To
>> >> >> > my knowledge when we have RF we shouldn't have any laser pulse and
>> >> >> > when the RF vanishes we should have laser pulse . it means &#2013266080; that when
>> >> >> > we compare two pulses &#2013266080;in the oscilloscope as soon as the square shape
>> >> >> > trigger pulse vanishes the laser pulse must &#2013266080;be appear &#2013266080;but it appears
>> >> >> > later in the train of the pulse . what is the problem ?
>> >> >> > Is the measuring equipment is poor or it has theoretical problem.
>> >> >> > Thanks in advance
>>
>> >> >> To start I'm reposting that to
>> >> >> sci . electronics . design
>> >> >> Regards
>> >> >> Ken
>> >> >> PS: One guys there is really smart, I don't know about the rest,
>> >> >> of the others.
>>
>> >> >Presumably the Q-switch is being driven by periodic signal - you get a
>> >> >burst of RF, then no RF, then another burst of RF in a pattern that
>> >> >repeats itself exactly.
>>
>> >> >The claim is that the laser pulse should appear when the RF has been
>> >> >switched off.
>>
>> >> No, the claim is that the laser pulse should appear when the trailing
>> >> edge of the Q-switch trigger happens.
>>
>> >Would you care to specify the repetition rate of the RF pulses? And
>> >the gap between the "disappearance" &#2013266080;of the RF pulse and the
>> >appearance of the laser pulse? The only time I had much to do with an
>> >argon ion laser, the natural period of the laser - set by the cavity
>> >length - was 80MHz, so the pulses would have appeared every 12.5nsec,
>> >but there was a Q-switch which allowed you to pick out single pulses
>> >from time to time. The 12.5 nsec corresponds to the time it takes for
>> >light to travel 12.5 feet, and you can can get that kind of signal
>> >propagation around a lash-up without trying very hard.
>>
>> What does all that crap have to do with anything?
>>
>> The man stated that he could see both the square trigger pulse from
>> the Q-switch and the pulse from the photodiode, but that the pulse
>> from the photodiode was appearing, not at the end of the trigger
>> pulse, as expected, but later on.
>>
>> He then asked if anyone could explain why that was happening.
>>
>> You then posted the following:
>>
>> >> >If the period being displayed on the oscilliscope screen is long
>> >> >enough to include two or more bursts of RF on one channel, the laser
>> >> >pulse being displayed from the other channel will show up between the
>> >> >two bursts of RF - the precise time relationship depends on how the Q-
>> >> >switch works.
>>
>> which indicates that you didn't understand that he had already stated
>> that he could see both pulses and was asking for the reason why they
>> weren't temporally aligned in the way he expected.
>
>reconstructing his observations in terms that suited the dieas that I
>was trying to get across.
>
>> >> He has no trouble seeing both signals, his concern is with the laser
>> >> pulse showing up later than it's supposed to.
>>
>> >Since he hasn't put any numbers on his expectations, he obviously
>> >hasn't started thinking about what is going on. Since you haven't
>> >either, your "later than it is supposed to" represents a comparable
>> >failure to engage what brain you've got.
>>
>> Since the premise is that the laser pulse should start _immediately_
>> following the termination of the trigger pulse, there are no numbers
>> required since the timing is inherent in the statement.
>
>Don't be stupid. Nothing starts "immediately". there are always
>propagation delays around the system, and if you get them wrong the
>laser pulse can show up on the screen before the end of the RF pulse
>which was supposed to have triggered it - but only if you've got a
>looong cable frpm the RF pulse gnerator to the scope
>
>> Since you don't aseem to be able to understand a string of words all
>> that well, here's a picture:
>>
>> &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; -->|<--dT = 0
>> &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080;____
>> TRIG____________| &#2013266080; &#2013266080;|_____________________
>> &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; &#2013266080; _
>> PD___________________| |___________________
>>
>> As usual, when you're wrong, instead of just admitting it and getting
>> on with your life you thrash around and hurl unwarranted invective in
>> a vain attempt to muddy the water and move the finger that's pointing
>> at you to point at something else. &#2013266080;Cheater.
>
>Don't be silly. You've invested a great deal in the idea that
>"immediately" means a picosecond precise alignement, when if you took
>thirty seconds to think about what you were you'd realise that this is
>nonsense.
>
>> >> >This doesn't sound like the sort of question that needs anybody really
>> >> >smart to answer it.
>>
>> Perhaps not, but since you couldn't answer it it would have to be
>> someone smarter than you.
>
>That may be your opinion. As usual, it hasn't got mucy to do with
>reality.
>
>> >> >If the OP had given some detail about the laser
>> >> >system and the Q-switch, there might be more that could be said by
>> >> >someone sufficiently well-informed (though not necessarily all that
>> >> >smart).
>>
>> Yeah, right, blame it on the OP.
>
>Who else?
>
>> >> First, one must learn to understand what he reads.
>>
>> >Sure. You've obviously failed that first step, since you haven't
>> >noticed that there wasn't a lot to understand.
>>
>> Since you didn't even get what little there was, it seems you've
>> hoisted yourself with your own petard in a deliciously ironic way.
>
>Dram on, nitwit.
>
>> Or as Shakespeare had Hamlet say:
>>
>> "For 'tis the sport to have the enginer / Hoist with his owne
>> petar" -- Hamlet III iv.
>
>The real irony is that you won't have noticed that _your_ little hand-
>cannon blew up in _your_ face, as Joe Legris has - very kindly - taken
>the trouble to point out.

---
"Very kindly" because he can't see through your bullshit, feels sorry
for you, and doesn't realize that you're getting your just deserts.

That loon seems to be cut from the same cloth you are, so his opinions
and technical competence are just as suspect as yours are.

BTW, I think I made my point well enough to make it clear that you
didn't understand the OP's post the first time around, so I'll just
leave it at that and leave you free to play your silly little evasive
games.

---
JF
```
```On Oct 26, 5:03=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> On Tue, 26 Oct 2010 06:48:35 -0700 (PDT), "J.A. Legris"
>
> <jaleg...@sympatico.ca> wrote:
> >On Oct 26, 7:36=A0am, John Fields <jfie...@austininstruments.com> wrote:
>
> >> Since you didn't even get what little there was, it seems you've
> >> hoisted yourself with your own petard in a deliciously ironic way.
>
> >> Or as Shakespeare had Hamlet say:
>
> >> "For 'tis the sport to have the enginer / Hoist with his owne
> >> petar" -- Hamlet III iv.
>
> >There's no greater irony here than the spectacle of you, an insecure
> >self-conscious low-brow, desperately trying to acquire an ounce of
> >self-respect through repeated unprovoked attacks on Sloman.
>
> If you think they're unprovoked, then you're cut from the same cloth
> he is and no doubt share the same delusions.
>
> >It's not working.
>
> Just for grins, let's say I _was_ trying to acquire some self respect
> that way. =A0How would you know it wasn't working?
>
> In fact, if I _didn't_ catch his errors and feed them back to him, I'd
> feel remiss and lacking in self-respect.

John Fields does catch my typos and feed them back to me. These are
real - if trivial - errors, which, granting his problems with sentence
comprehension, are  more salient for him than they are to the rest of
us.

Unfortunately, because he can't comprehend complex sentences, he often
thinks I've said something wrong when in fact I haven't and indulges
himself in quixotic campaigns to get me to achknowledge my - non-
existent - error.

Quite how these demeneted campaigns feed his self-respect is left as
an exercise for the reader. I've got very little idea of how his mind

> >Maybe you should go back to calling yourself "Professional
> >Circuit Designer" or even "El Presidente", but then those didn't work
> >either did they?
>
> Times change, and I see now that you've been in my shit for a long
> while, yes?
>
> Either that or you've been checking my posting history from way back
> when.
>
> Why, I wonder?

> >Quoting Shakespeare is just another bad idea.
>
> For you, maybe, but I find his stuff pretty good, and often apt, so I
> can't imagine why you'd foist your limitations on me.
>
> >You may achieve more success if you simply avoid trusting your
> >instincts and, like George Constanza, just do the opposite!
>
> Well, if I ever get ready for a canned sit-com life, which is where
> you seem to be coming from, you'll be the first one I call for advice
> on which character to play.
>
> In the meantime, Newman, try to get back on topic and mind your own

Charming as ever.

--
Bill Sloman, Nijmegen

```
```On Oct 26, 5:19=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> On Tue, 26 Oct 2010 07:52:16 -0700 (PDT), Bill Sloman
>
> <bill.slo...@ieee.org> wrote:
> >On Oct 26, 1:36=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> >> On Mon, 25 Oct 2010 16:22:22 -0700 (PDT), Bill Sloman
>
> >> <bill.slo...@ieee.org> wrote:
> >> >On Oct 25, 7:23=A0pm, John Fields <jfie...@austininstruments.com> wro=
te:
> >> >> On Mon, 25 Oct 2010 09:42:54 -0700 (PDT), Bill Sloman
>
> >> >> <bill.slo...@ieee.org> wrote:
> >> >> >On Oct 25, 5:36=A0pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrot=
e:
> >> >> >> This was posted in sci.physics.research.
>
> >> >> >> On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>
> >> >> >> > Dear Friends
> >> >> >> > =A0I want to do some experiment in pulsed laser. I attached ou=
tput of a
> >> >> >> > laser to one channel of oscilloscope via photodiode to see the=
shape
> >> >> >> > of the pulse. then I attach the =A0one output of =A0RF trigger=
of the
> >> >> >> > qswitch to the other channel of the oscilloscope =A0to see the=
=A0square
> >> >> >> > shape pulse =A0of the =A0Rf trigger till now everything is ok =
I can see
> >> >> >> > both pulses. But I can't interpret the relation between two pu=
lses. To
> >> >> >> > my knowledge when we have RF we shouldn't have any laser pulse=
and
> >> >> >> > when the RF vanishes we should have laser pulse . it means =A0=
that when
> >> >> >> > we compare two pulses =A0in the oscilloscope as soon as the sq=
uare shape
> >> >> >> > trigger pulse vanishes the laser pulse must =A0be appear =A0bu=
t it appears
> >> >> >> > later in the train of the pulse . what is the problem ?
> >> >> >> > Is the measuring equipment is poor or it has theoretical probl=
em.
> >> >> >> > Thanks in advance
>
> >> >> >> To start I'm reposting that to
> >> >> >> sci . electronics . design
> >> >> >> Regards
> >> >> >> Ken
> >> >> >> PS: One guys there is really smart, I don't know about the rest,
> >> >> >> of the others.
>
> >> >> >Presumably the Q-switch is being driven by periodic signal - you g=
et a
> >> >> >burst of RF, then no RF, then another burst of RF in a pattern tha=
t
> >> >> >repeats itself exactly.
>
> >> >> >The claim is that the laser pulse should appear when the RF has be=
en
> >> >> >switched off.
>
> >> >> No, the claim is that the laser pulse should appear when the traili=
ng
> >> >> edge of the Q-switch trigger happens.
>
> >> >Would you care to specify the repetition rate of the RF pulses? And
> >> >the gap between the "disappearance" =A0of the RF pulse and the
> >> >appearance of the laser pulse? The only time I had much to do with an
> >> >argon ion laser, the natural period of the laser - set by the cavity
> >> >length - was 80MHz, so the pulses would have appeared every 12.5nsec,
> >> >but there was a Q-switch which allowed you to pick out single pulses
> >> >from time to time. The 12.5 nsec corresponds to the time it takes for
> >> >light to travel 12.5 feet, and you can can get that kind of signal
> >> >propagation around a lash-up without trying very hard.
>
> >> What does all that crap have to do with anything?
>
> >> The man stated that he could see both the square trigger pulse from
> >> the Q-switch and the pulse from the photodiode, but that the pulse
> >> from the photodiode was appearing, not at the end of the trigger
> >> pulse, as expected, but later on.
>
> >> He then asked if anyone could explain why that was happening.
>
> >> You then posted the following:
>
> >> >> >If the period being displayed on the oscilliscope screen is long
> >> >> >enough to include two or more bursts of RF on one channel, the las=
er
> >> >> >pulse being displayed from the other channel will show up between =
the
> >> >> >two bursts of RF - the precise time relationship depends on how th=
e Q-
> >> >> >switch works.
>
> >> which indicates that you didn't understand that he had already stated
> >> that he could see both pulses and was asking for the reason why they
> >> weren't temporally aligned in the way he expected.
>
> >reconstructing his observations in terms that suited the ideas that I
> >was trying to get across.
>
> >> >> He has no trouble seeing both signals, his concern is with the lase=
r
> >> >> pulse showing up later than it's supposed to.
>
> >> >Since he hasn't put any numbers on his expectations, he obviously
> >> >hasn't started thinking about what is going on. Since you haven't
> >> >either, your "later than it is supposed to" represents a comparable
> >> >failure to engage what brain you've got.
>
> >> Since the premise is that the laser pulse should start _immediately_
> >> following the termination of the trigger pulse, there are no numbers
> >> required since the timing is inherent in the statement.
>
> >Don't be stupid. Nothing starts "immediately". there are always
> >propagation delays around the system, and if you get them wrong the
> >laser pulse can show up on the screen before the end of the RF pulse
> >which was supposed to have triggered it - but only if you've got a
> >looong cable frpm the RF pulse gnerator to the scope
>
> >> Since you don't aseem to be able to understand a string of words all
> >> that well, here's a picture:
>
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 -->|<--dT =3D 0
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0____
> >> TRIG____________| =A0 =A0|_____________________
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 _
> >> PD___________________| |___________________
>
> >> As usual, when you're wrong, instead of just admitting it and getting
> >> on with your life you thrash around and hurl unwarranted invective in
> >> a vain attempt to muddy the water and move the finger that's pointing
> >> at you to point at something else. =A0Cheater.
>
> >Don't be silly. You've invested a great deal in the idea that
> >"immediately" means a picosecond precise alignement, when if you took
> >thirty seconds to think about what you were you'd realise that this is
> >nonsense.
>
> >> >> >This doesn't sound like the sort of question that needs anybody re=
ally
> >> >> >smart to answer it.
>
> >> Perhaps not, but since you couldn't answer it it would have to be
> >> someone smarter than you.
>
> >That may be your opinion. As usual, it hasn't got mucy to do with
> >reality.
>
> >> >> >If the OP had given some detail about the laser
> >> >> >system and the Q-switch, there might be more that could be said by
> >> >> >someone sufficiently well-informed (though not necessarily all tha=
t
> >> >> >smart).
>
> >> Yeah, right, blame it on the OP.
>
> >Who else?
>
> >> >> First, one must learn to understand what he reads.
>
> >> >Sure. You've obviously failed that first step, since you haven't
> >> >noticed that there wasn't a lot to understand.
>
> >> Since you didn't even get what little there was, it seems you've
> >> hoisted yourself with your own petard in a deliciously ironic way.
>
> >Dream on, nitwit.
>
> >> Or as Shakespeare had Hamlet say:
>
> >> "For 'tis the sport to have the enginer / Hoist with his owne
> >> petar" -- Hamlet III iv.
>
> >The real irony is that you won't have noticed that _your_ little hand-
> >cannon blew up in _your_ face, as Joe Legris has - very kindly - taken
> >the trouble to point out.
>
> ---
> "Very kindly" because he can't see through your bullshit, feels sorry
> for you, and doesn't realize that you're getting your just deserts.

You may like to see it that way. It's not a point of view that anybody
else is likely to share.

> That loon seems to be cut from the same cloth you are, so his opinions
> and technical competence are just as suspect as yours are.

When measured against John Field's infallible expertise. Which mostly
seems to concern the care an feeding of the 555, which most people
stopped using around 1980.

> BTW, I think I made my point well enough to make it clear that you
> didn't understand the OP's post the first time around, so I'll just
> leave it at that and leave you free to play your silly little evasive
> games.

Which is to say that John Fields hasn't yet come to terms with the
fact that he can't reliably parse complex sentences.

--
Bill Sloman, Nijmegen

```
```"J.A. Legris" wrote:
>
> There's no greater irony here than the spectacle of you, an insecure
> self-conscious low-brow, desperately trying to acquire an ounce of
> self-respect through repeated unprovoked attacks on Sloman.

Here is an example of Sloman's unprovoked attacks.  To an obviously
forged message, no less:

------------------

Subject:
Re: Any Smart DumbAss in here knows How to Increase the
Capacitance of Electrolyte Capacitor?
Date:
Sun, 9 Mar 2008 04:42:53 -0700 (PDT)
From:
bill.sloman@ieee.org
Organization:
Newsgroups:
sci.electronics.components, sci.electronics.design,
sci.electronics.repair
References:
1

On Mar 9, 10:47 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> Hello folks,
>
> I am getting cheap these days, I am trying to cut corner by tripling the
> capacitance in the capacitor, is this possible?  I have heard that it's
> possible.  Some people have done it successfully.  I am just wondering if
> any of you smart dumbass can help.

If you weren't quite the ill-informed idiot that you are, you'd know
that the dielectric in an electrolytic capacitor is formed by the
electrolytic oxidation of the surface of the aluminium foil the forms
the plates of the capacitor.

If you reverse bias the capacitor you can reverse this process, making
the dielectric thinner ( and more likely to break down). Sadly, the
reverse process is unlikely to thin the oxide layer to exactly the
same extent at every point, so you run the risk of lowering the
breakdown voltage faster than you increase the capacitance.

As cheap goes, this about a poor and investment of your time as you
could make - short of slandering me in this user group which however
does seem to give you some kind of demented satisfaction - but do try
it. You won't enjoy the process at all, but does that worry me?

--
Bill Sloman, Nijmegen

------------------

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.
```
```On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote:
> On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>
>
>
> > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>
> > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>
> > > > This was posted in sci.physics.research.
>
> > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>
> > > > > Dear Friends
> > > > >  I want to do some experiment in pulsed laser. I attached output of a
> > > > > laser to one channel of oscilloscope via photodiode to see the shape
> > > > > of the pulse. then I attach the  one output of  RF trigger of the
> > > > > qswitch to the other channel of the oscilloscope  to see the  square
> > > > > shape pulse  of the  Rf trigger till now everything is ok I can see
> > > > > both pulses. But I can't interpret the relation between two pulses. To
> > > > > my knowledge when we have RF we shouldn't have any laser pulse and
> > > > > when the RF vanishes we should have laser pulse . it means   that when
> > > > > we compare two pulses  in the oscilloscope as soon as the square shape
> > > > > trigger pulse vanishes the laser pulse must  be appear  but it appears
> > > > > later in the train of the pulse . what is the problem ?
> > > > > Is the measuring equipment is poor or it has theoretical problem.
> > > > > Thanks in advance
>
> > > > To start I'm reposting that to
> > > > sci . electronics . design
> > > > Regards
> > > > Ken
> > > > PS: One guys there is really smart, I don't know about the rest,
> > > > of the others.
>
> > > Presumably the Q-switch is being driven by periodic signal - you get a
> > > burst of RF, then no RF, then another burst of RF in a pattern that
> > > repeats itself exactly.
>
> > > The claim is that the laser pulse should appear when the RF has been
> > > switched off.
>
> > > If the period being displayed on the oscilliscope screen is long
> > > enough to include two or more bursts of RF on one channel, the laser
> > > pulse being displayed from the other channel will show up between the
> > > two bursts of RF - the precise time relationship depends on how the Q-
> > > switch works.
>
> > > This doesn't sound like the sort of question that needs anybody really
> > > smart to answer it. If the OP had given some detail about the laser
> > > system and the Q-switch, there might be more that could be said by
> > > someone sufficiently well-informed (though not necessarily all that
> > > smart).
> > > Bill Sloman, Nijmegen
>
> > I single handidly invented the optical world! (had some help though).
> > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km,
> > watch the return on the scope, reckon dispersion, that's how the
> > pulse base spread a bit, and from that 'ballpark' a max fequency,
> > for that particular fibre media.
> > Next thing we had to do was join and tap the fibre, cost was no
> > object, except my pay.
> > Obviously, I'm a bit rusty, so I posted this for those who might
> > understand what the fella (OP from spr) is driving at.
>
> Bully for you. Why did we need to know that?

Sorry I missed your post Mr. Sloman, like most, we read the
interesting
peoples posts 1st and eventually get around to you.
To your question, as I explained, I (we) did that sort of thing around
1980, measuring how square waves got rounded etc, but I didn't
quite understand the 'jargon' of the OP.
Do you understand it now again?
Ken

```
```On Oct 27, 5:38=A0am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
> On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>
>
>
> > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>
> > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>
> > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>
> > > > > This was posted in sci.physics.research.
>
> > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>
> > > > > > Dear Friends
> > > > > > =A0I want to do some experiment in pulsed laser. I attached out=
put of a
> > > > > > laser to one channel of oscilloscope via photodiode to see the =
shape
> > > > > > of the pulse. then I attach the =A0one output of =A0RF trigger =
of the
> > > > > > qswitch to the other channel of the oscilloscope =A0to see the =
=A0square
> > > > > > shape pulse =A0of the =A0Rf trigger till now everything is ok I=
can see
> > > > > > both pulses. But I can't interpret the relation between two pul=
ses. To
> > > > > > my knowledge when we have RF we shouldn't have any laser pulse =
and
> > > > > > when the RF vanishes we should have laser pulse . it means =A0 =
that when
> > > > > > we compare two pulses =A0in the oscilloscope as soon as the squ=
are shape
> > > > > > trigger pulse vanishes the laser pulse must =A0be appear =A0but=
it appears
> > > > > > later in the train of the pulse . what is the problem ?
> > > > > > Is the measuring equipment is poor or it has theoretical proble=
m.
> > > > > > Thanks in advance
>
> > > > > To start I'm reposting that to
> > > > > sci . electronics . design
> > > > > Regards
> > > > > Ken
> > > > > PS: One guys there is really smart, I don't know about the rest,
> > > > > of the others.
>
> > > > Presumably the Q-switch is being driven by periodic signal - you ge=
t a
> > > > burst of RF, then no RF, then another burst of RF in a pattern that
> > > > repeats itself exactly.
>
> > > > The claim is that the laser pulse should appear when the RF has bee=
n
> > > > switched off.
>
> > > > If the period being displayed on the oscilliscope screen is long
> > > > enough to include two or more bursts of RF on one channel, the lase=
r
> > > > pulse being displayed from the other channel will show up between t=
he
> > > > two bursts of RF - the precise time relationship depends on how the=
Q-
> > > > switch works.
>
> > > > This doesn't sound like the sort of question that needs anybody rea=
lly
> > > > smart to answer it. If the OP had given some detail about the laser
> > > > system and the Q-switch, there might be more that could be said by
> > > > someone sufficiently well-informed (though not necessarily all that
> > > > smart).
> > > > Bill Sloman, Nijmegen
>
> > > I single handidly invented the optical world! (had some help though).
> > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km,
> > > watch the return on the scope, reckon dispersion, that's how the
> > > pulse base spread a bit, and from that 'ballpark' a max fequency,
> > > for that particular fibre media.
> > > Next thing we had to do was join and tap the fibre, cost was no
> > > object, except my pay.
> > > Obviously, I'm a bit rusty, so I posted this for those who might
> > > understand what the fella (OP from spr) is driving at.
>
> > Bully for you. Why did we need to know that?
>
> Sorry I missed your post Mr. Sloman, like most, we read the
> interesting peoples posts 1st and eventually get around to you.

Dr.Sloman.

> To your question, as I explained, I (we) did that sort of thing around
> 1980, measuring how square waves got rounded etc, but I didn't
> quite understand the 'jargon' of the OP.
> Do you understand it now again?

I didn't see the OP's post as jargon. He obviously hadn't reflected on
the significance of what he was seeing - otherwise he would have told
us the time delay between the end of the RF pulse to the Q-switch and
the appearance of the laser pulse - but his description of what was
going on was explicit enough, if not particulalry detailed.

If you have had the experience with optical signals that you claim,
you should be able to find out the propagation delay (from photo-
cathode to anode) of a fast linear-focussed photomultiplier tube,
which might well be relevant to the OP's query.

--
Bill Sloman, Nijmegen

```
```On Wed, 27 Oct 2010 02:34:32 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

>On Oct 27, 5:38&#2013266080;am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>> On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>>
>>
>>
>> > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>>
>> > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote:
>>
>> > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
>>
>> > > > > This was posted in sci.physics.research.
>>
>> > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote:
>>
>> > > > > > Dear Friends
>> > > > > > &#2013266080;I want to do some experiment in pulsed laser. I attached output of a
>> > > > > > laser to one channel of oscilloscope via photodiode to see the shape
>> > > > > > of the pulse. then I attach the &#2013266080;one output of &#2013266080;RF trigger of the
>> > > > > > qswitch to the other channel of the oscilloscope &#2013266080;to see the &#2013266080;square
>> > > > > > shape pulse &#2013266080;of the &#2013266080;Rf trigger till now everything is ok I can see
>> > > > > > both pulses. But I can't interpret the relation between two pulses. To
>> > > > > > my knowledge when we have RF we shouldn't have any laser pulse and
>> > > > > > when the RF vanishes we should have laser pulse . it means &#2013266080; that when
>> > > > > > we compare two pulses &#2013266080;in the oscilloscope as soon as the square shape
>> > > > > > trigger pulse vanishes the laser pulse must &#2013266080;be appear &#2013266080;but it appears
>> > > > > > later in the train of the pulse . what is the problem ?
>> > > > > > Is the measuring equipment is poor or it has theoretical problem.
>> > > > > > Thanks in advance
>>
>> > > > > To start I'm reposting that to
>> > > > > sci . electronics . design
>> > > > > Regards
>> > > > > Ken
>> > > > > PS: One guys there is really smart, I don't know about the rest,
>> > > > > of the others.
>>
>> > > > Presumably the Q-switch is being driven by periodic signal - you get a
>> > > > burst of RF, then no RF, then another burst of RF in a pattern that
>> > > > repeats itself exactly.
>>
>> > > > The claim is that the laser pulse should appear when the RF has been
>> > > > switched off.
>>
>> > > > If the period being displayed on the oscilliscope screen is long
>> > > > enough to include two or more bursts of RF on one channel, the laser
>> > > > pulse being displayed from the other channel will show up between the
>> > > > two bursts of RF - the precise time relationship depends on how the Q-
>> > > > switch works.
>>
>> > > > This doesn't sound like the sort of question that needs anybody really
>> > > > smart to answer it. If the OP had given some detail about the laser
>> > > > system and the Q-switch, there might be more that could be said by
>> > > > someone sufficiently well-informed (though not necessarily all that
>> > > > smart).
>> > > > Bill Sloman, Nijmegen
>>
>> > > I single handidly invented the optical world! (had some help though).
>> > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km,
>> > > watch the return on the scope, reckon dispersion, that's how the
>> > > pulse base spread a bit, and from that 'ballpark' a max fequency,
>> > > for that particular fibre media.
>> > > Next thing we had to do was join and tap the fibre, cost was no
>> > > object, except my pay.
>> > > Obviously, I'm a bit rusty, so I posted this for those who might
>> > > understand what the fella (OP from spr) is driving at.
>>
>> > Bully for you. Why did we need to know that?
>>
>> Sorry I missed your post Mr. Sloman, like most, we read the
>> interesting peoples posts 1st and eventually get around to you.
>
>Dr.Sloman.

---
Actually, comparing you to Dr. Hobbs leads to the inescapable
conclusion that 'Mr.' suits you better.
---

>> To your question, as I explained, I (we) did that sort of thing around
>> 1980, measuring how square waves got rounded etc, but I didn't
>> quite understand the 'jargon' of the OP.
>> Do you understand it now again?
>
>I didn't see the OP's post as jargon.

---
Neither did Ken. Did you miss the single quotes around jargon?
---

>the significance of what he was seeing - otherwise he would have told
>us the time delay between the end of the RF pulse to the Q-switch and
>the appearance of the laser pulse - but his description of what was
>going on was explicit enough, if not particulalry detailed.

---
Back-pedaling, huh?
---

>If you have had the experience with optical signals that you claim,
>you should be able to find out the propagation delay (from photo-
>cathode to anode) of a fast linear-focussed photomultiplier tube,
>which might well be relevant to the OP's query.

---
Blah, blah, blah...

---
JF
```