Floating the 'scope

[Fred Abse]

On Sun, 07 Mar 2010 07:06:08 -0600, phantom wrote:

How many screens will it window?

I'll have to check that on Monday, but I've never needed more.


7A13 will measure a 1mV portion of a 10V signal.

10 volt offset is the max the 7A13 can do.

That's at 1mV per division.
+/-100V at 10mV to 50mV per division
+/-500V at 0.1 to 0.5V per division
+/-500V at 1V to 5V per division.
Displayed voltage multiplied by 10 when x10 probe
sensed.
IOW, the +/- offset voltage can be applied to either input without
attenuation. It's a true slideback measurement using a variable
voltage and built-in DVM.

The TPS2024 can do way more
than that for large signals.

I guess you mean at greater input attenuator settings?

As can the 7A13

Does it have a calibrated comparison voltage? Useful for things like
measuring staircase steps.

The value of the offset is displayed as a 3 digit number on screen. The
deflection factor is also calibrated.

The 7A13 offset is actually a "real" DC voltage, indicated by a "real" DVM.
Also available at a front panel socket for external measurement.

There aren't many instruments whose deflection factor isn't calibrated.
They wouldn't be of much use without.

You only get one differential channel per 7A13. Each isolated channel
on the TPS2024 is a differential input when the ground clip can be
connected anywhere, so there are 4 differential channels.

I've never needed 4 differential channels, but if I did, I'd use two
mainframes and four 7a13s (Yes, I do have four)

When using two mainframes, how do you see all four traces on the same
screen?

You don't. You use two screens.

I've used a 7a13 for vertical deflection on a couple of occasions.

Isn't vertical deflection the usual mode? Maybe you mean that you used a
7A13 for horizontal deflection. Isn't that what you'd have to do for X-Y
mode?

You're right, I meant horizontal (X). I tend to think "X and Y". My mistake.
Peccavi et mea freakin' culpa!

You can
put amplifiers in timebase slots. Full differential X-Y.

Most modern scopes have an X-Y mode; so does the TPS2024. Since all the
channels on the TPS2024 are effectively differential, its X-Y mode is a
differential X-Y mode

I don't think I've ever had a 'scope that wouldn't do X-Y. going back 40 years.
Some had restricted X bandwidth.


--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[whit3rd]

On Mar 6, 3:51 am, John Tserkezis
<j...@techniciansyndrome.org.invalid> wrote:

 Though it still needs to be said, if someone is of the mentality that
they can freely dismantle a piece of equipment that says "do not
dismantle" to intentionally remove a safety mechanism ...

Lotsa luck selling the 'don't tamper' argument on this newsgroup.
Better to point out the option of making a CLEARLY VISIBLE
indication of the floating case, like a hulking isolation transformer
next to the 'scope.

Floating the 'scope is one of the great useful techniques, it
must be implemented somehow on a good test workbench.

 

[default]

On Fri, 5 Mar 2010 19:05:54 -0800 (PST), George Herold
<ggherold@gmail.com> wrote:

Why do they make 'scope inputs ground referenced to the third wire of
the AC plug? Today I smoked the 10 ohm resistor that was separating
The AC ground from the 'ground' of my circuit. I'd forgotten to float
the 'scope and connected -15V to the ground clip of the scope probe.

George H.

Think about it.

The scope has a very high input impedance. With no ground, common
mode unbalanced hash (inductive or electrostatic) will always give one
a wave form - but not necessarily any useful one.

That's one of the reasons you have two channels - one for the signal,
one for the reference - and both shielded from common mode noise, A+B
or dual/add etc.

Learn to use your scope. A B&K scope made for TV servicing might have
a floating ground - but unless your' re servicing TV's and only need a
high frequency of 20 KHZ, you probably don't want some specialized,
idiot proof, scope.

The scope is part of the "circuit under test," your body (room, power
distribution network, etc.) is part of the circuit too. Think about
it and learn to deal with it.

Those little pigtails from the scope probe with the ground alligator?
aren't for convenience - they reduce noise pickup. Likewise a really
serious switching circuit could require a very short wire to the
ground slip ring at the tip of the scope and circuit under test.

Every circuit is an RF circuit if it has switching transients.
--

 

On Sun, 07 Mar 2010 11:30:16 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 07 Mar 2010 07:06:08 -0600, phantom wrote:

How many screens will it window?

I'll have to check that on Monday, but I've never needed more.


7A13 will measure a 1mV portion of a 10V signal.

10 volt offset is the max the 7A13 can do.

That's at 1mV per division.
+/-100V at 10mV to 50mV per division
+/-500V at 0.1 to 0.5V per division
+/-500V at 1V to 5V per division.
Displayed voltage multiplied by 10 when x10 probe
sensed.
IOW, the +/- offset voltage can be applied to either input without
attenuation. It's a true slideback measurement using a variable
voltage and built-in DVM.

Sufficient offset range achieves the same measurement result.

The TPS2024 can do way more
than that for large signals.

I guess you mean at greater input attenuator settings?

As can the 7A13



Does it have a calibrated comparison voltage? Useful for things like
measuring staircase steps.

The value of the offset is displayed as a 3 digit number on screen. The
deflection factor is also calibrated.

The 7A13 offset is actually a "real" DC voltage, indicated by a "real" DVM.
Also available at a front panel socket for external measurement.

I see no advantage to being able to measure it at a front panel socket
compared to having the scope tell you what the offset voltage is.

There aren't many instruments whose deflection factor isn't calibrated.
They wouldn't be of much use without.

You mentioned "calibrated comparison voltage" and "measuring
staircase steps". The calibrated deflection factor serves the
function just as well.

You only get one differential channel per 7A13. Each isolated channel
on the TPS2024 is a differential input when the ground clip can be
connected anywhere, so there are 4 differential channels.

I've never needed 4 differential channels, but if I did, I'd use two
mainframes and four 7a13s (Yes, I do have four)

When using two mainframes, how do you see all four traces on the same
screen?

You don't. You use two screens.

Hardly the same as having four color traces on one screen, is it?

I've used a 7a13 for vertical deflection on a couple of occasions.

Isn't vertical deflection the usual mode? Maybe you mean that you used a
7A13 for horizontal deflection. Isn't that what you'd have to do for X-Y
mode?

You're right, I meant horizontal (X). I tend to think "X and Y". My mistake.
Peccavi et mea freakin' culpa!


You can
put amplifiers in timebase slots. Full differential X-Y.

Most modern scopes have an X-Y mode; so does the TPS2024. Since all the
channels on the TPS2024 are effectively differential, its X-Y mode is a
differential X-Y mode

I don't think I've ever had a 'scope that wouldn't do X-Y. going back 40 years.
Some had restricted X bandwidth.

Indeed. So since I had already told you that the TPS2024 had 4
effectively differential inputs, why did you mention "You can
put amplifiers in timebase slots. Full differential X-Y." as though
that were an advantage that the 7A13 has that the TPS2024 doesn't?

This whole back and forth seems to consist of you telling me things
that the 7A13 can do that the TPS2024 can't. So for, I see that the
TPS2024 substantially outshines the 7A13. Others can draw their own
conclusions.

 

[John Larkin]

On Sun, 07 Mar 2010 01:38:48 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sat, 06 Mar 2010 18:31:01 -0600, The Phantom wrote:

On Sat, 06 Mar 2010 15:59:17 -0800, Fred Abse
excretatauris@invalid.invalid> wrote:

On Sat, 06 Mar 2010 17:37:01 -0600, The Phantom wrote:

On Sat, 06 Mar 2010 15:25:03 -0800, Fred Abse
excretatauris@invalid.invalid> wrote:

On Sat, 06 Mar 2010 14:26:01 -0600, The Phantom wrote:

On Sat, 06 Mar 2010 07:03:56 -0500, Hammy <spam@spam.com> wrote:

On 6 Mar 2010 03:09:01 -0600, The Phantom <phantom@aol.com> wrote:



Tektronix has probes designed to solve these problems:

http://www2.tek.com/cmswpt/psdetails.lotr?ct=PS&cs=psu&ci=13471&lc=EN

They are specifically intended for floating use with the TPS2000
series scopes, which, as John mentioned, have true isolated inputs.

Or, you can use these probes with an ordinary scope:

http://www2.tek.com/cmswpt/psdetails.lotr?ct=PS&cs=psu&ci=13415&lc=EN

Those are nice expensive but nice.

You should use an isolation transformer on any line powered device
your testing. You can usually find a 500VA one for under 100 bucks. I
got a TEMA 500VA one for 45 bucks from Newark. Well worth the money.

Its not really a good idea to float your scope.

A problem arises when you need to make measurements with a 2 or 4
channel scope at locations in the circuit which don't have a common
reference.

For example, suppose you need to look at the gate-source voltages of
the two top MOSFETs in an H-bridge configuration. Isolating the
equipment doesn't allow you to connect the ground clips of the two
scope probes to different points in the circuit that have a
substantial voltage difference.

You need to use floating differential probes, or a scope with true
isolated inputs.

7904, two 7A13s, job done.

TPS2024. No plugins. 4 channels. Job done, and battery operation for
ultimate portability.

No comparator / voltage slideback function.

That's what the vertical offset knob is for.

How many screens will it window?

7A13 will measure a 1mV portion of a 10V signal.


Does it have a calibrated comparison voltage? Useful for things like
measuring staircase steps.


You only get one differential channel per 7A13. Each isolated channel on
the TPS2024 is a differential input when the ground clip can be connected
anywhere, so there are 4 differential channels.

I've never needed 4 differential channels, but if I did, I'd use two
mainframes and four 7a13s (Yes, I do have four)

I've used a 7a13 for vertical deflection on a couple of occasions. You can
put amplifiers in timebase slots. Full differential X-Y.

A 7A13 is wonderful in lots of apps, but it won't do differential
input and offset at the same time.

If I have, say, a power amp with +-200 volt rails, and I want to
measure the waveform across a small-value resistor flailing around
with the output voltage, the TPS is perfect. And the traces are in
color!


John

 

[Fred Abse]

On Sun, 07 Mar 2010 19:27:01 -0600, phantom wrote:

This whole back and forth seems to consist of you telling me things that
the 7A13 can do that the TPS2024 can't. So for, I see that the TPS2024
substantially outshines the 7A13. Others can draw their own conclusions.

Just one point, then, The 7A13 will measure a 1mV portion of a 10V signal.
That's nearly four times the 8 bits resolution, which I believe the
TPS2024 has.


--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[Fred Abse]

On Sun, 07 Mar 2010 17:44:14 -0800, John Larkin wrote:

7A13 is wonderful in lots of apps, but it won't do differential input
and offset at the same time.

Two 7A13s, mainframe set to add, channel 1 Vc to -ve, channel 2 Vc to +ve.

Never done it, but I'll try when I get a chance. CMRR won't be as good,
admittedly.

If I have, say, a power amp with +-200 volt rails, and I want to measure
the waveform across a small-value resistor flailing around with the
output voltage, the TPS is perfect. And the traces are in color!

Never could get along with digital 'scopes. Only use one when I want to
save or print a trace.

I find different-colored traces confusing. I see colors as numbers. Can
you color the traces in number order - R, Or, Y, G, etc? That might work
for me.

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[John Larkin]

On Mon, 08 Mar 2010 01:44:35 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 07 Mar 2010 17:44:14 -0800, John Larkin wrote:

7A13 is wonderful in lots of apps, but it won't do differential input
and offset at the same time.

Two 7A13s, mainframe set to add, channel 1 Vc to -ve, channel 2 Vc to +ve.

That's like using two probes in A-B mode. The equivalentcommon-mode
rrange is small, because the internal amps saturate at the equivalent
of a couple of screens worth of offset. The TPS can show tou a 10
millivolt signal riding on the AC line, with 200 MHz bandwidth.

The 7A13 is great for huge amounts of zooming, like looking at pulse
tops or recovery to zero. It recovers from massive overloads
instantly, which most scopes don't do very well.

Never done it, but I'll try when I get a chance. CMRR won't be as good,
admittedly.


If I have, say, a power amp with +-200 volt rails, and I want to measure
the waveform across a small-value resistor flailing around with the
output voltage, the TPS is perfect. And the traces are in color!

Never could get along with digital 'scopes. Only use one when I want to
save or print a trace.

I find different-colored traces confusing. I see colors as numbers. Can
you color the traces in number order - R, Or, Y, G, etc? That might work
for me.

Nowadays I find all-green scopes confusing. And I know that the purple
probe is the purple trace. Nice.

John

 

[John Larkin]

On Mon, 8 Mar 2010 07:53:52 -0800 (PST), George Herold
<ggherold@gmail.com> wrote:

On Mar 8, 4:44 am, Fred Abse <excretatau...@invalid.invalid> wrote:
On Sun, 07 Mar 2010 17:44:14 -0800, John Larkin wrote:
 7A13 is wonderful in lots of apps, but it won't do differential input
and offset at the same time.

Two 7A13s, mainframe set to add, channel 1 Vc to -ve, channel 2 Vc to +ve.

Never done it, but I'll try when I get a chance. CMRR won't be as good,
admittedly.



If I have, say, a power amp with +-200 volt rails, and I want to measure
the waveform across a small-value resistor flailing around with the
output voltage, the TPS is perfect. And the traces are in color!

Never could get along with digital 'scopes. Only use one when I want to
save or print a trace.

I find different-colored traces confusing. I see colors as numbers. Can
you color the traces in number order - R, Or, Y, G, etc? That might work
for me.

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)

Digital scopes use to have terrible user interfaces. But they are so
much better now. The colored knobs are associated with the trace
color. It's so easy to know which knob to grab... try it you may
like it.

George H.

Yeah, some of the early digital scopes, especially the HPs, were
nightmares to drive. It turns out that the classic arrangement of
knobs is best, so most digital scopes now resemble old analog scopes.

John

 

[George Herold]

On Mar 7, 1:08 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

George Herold wrote:

On Mar 6, 5:04 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
The Phantom wrote:

As I asked John, why would anyone go to the trouble to get inside a piece of
equipment to disconnect the safety ground, when they can just use a ground
buster at the wall socket?

  Most idiots just cut the ground pin off the power cord.

--
Greed is the root of all eBay.

Yup, I'm just like most idiots!  (But I put green tape on both ends of
the cord.)  The ground buster was before the universal AC input.

   Good for you.  That would get you fired any place I've ever worked.
If you needed isolation, you plugged whatever you were working on into
an isolation transformer.  If OSHA found a cord like that, the company
would be fined and it could run into thousands of dollars.

--
Greed is the root of all eBay.- Hide quoted text -

- Show quoted text -

Thanks Michael, The isolation transformer is on order.

George H.

 

[Michael A. Terrell]

George Herold wrote:

Michael A. Terrell wrote:

Good for you. That would get you fired any place I've ever worked.
If you needed isolation, you plugged whatever you were working on into
an isolation transformer. If OSHA found a cord like that, the company
would be fined and it could run into thousands of dollars.

Thanks Michael, The isolation transformer is on order.

Good deal! Just don't get careless when using it.


--
Greed is the root of all eBay.

 

[George Herold]

On Mar 8, 4:44 am, Fred Abse <excretatau...@invalid.invalid> wrote:

On Sun, 07 Mar 2010 17:44:14 -0800, John Larkin wrote:
 7A13 is wonderful in lots of apps, but it won't do differential input
and offset at the same time.

Two 7A13s, mainframe set to add, channel 1 Vc to -ve, channel 2 Vc to +ve..

Never done it, but I'll try when I get a chance. CMRR won't be as good,
admittedly.



If I have, say, a power amp with +-200 volt rails, and I want to measure
the waveform across a small-value resistor flailing around with the
output voltage, the TPS is perfect. And the traces are in color!

Never could get along with digital 'scopes. Only use one when I want to
save or print a trace.

I find different-colored traces confusing. I see colors as numbers. Can
you color the traces in number order - R, Or, Y, G, etc? That might work
for me.

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)

Digital scopes use to have terrible user interfaces. But they are so
much better now. The colored knobs are associated with the trace
color. It's so easy to know which knob to grab... try it you may
like it.

George H.

 

[Fred Abse]

On Mon, 08 Mar 2010 07:53:52 -0800, George Herold wrote:

Digital scopes use to have terrible user interfaces. But they are so much
better now. The colored knobs are associated with the trace color. It's
so easy to know which knob to grab... try it you may like it.

If I can find one with better than 500Mhz effective bandwidth, 12 bit or
better resolution and no Windows interface, I'll probably buy one.

Had a rep a while ago trying to sell me one of Tek's offerings. Switched
it on, up came "My Oscilloscope" or some other Windows "My Little Pony"
crap. Switched it off and sent him packing.

They'll be painting them pink, next

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[Fred Abse]

On Mon, 08 Mar 2010 08:29:57 -0800, John Larkin wrote:

That's like using two probes in A-B mode. The equivalentcommon-mode rrange
is small, because the internal amps saturate at the equivalent of a couple
of screens worth of offset.

Pretty much what I said.

The TPS can show tou a 10 millivolt signal
riding on the AC line, with 200 MHz bandwidth.

With only 8 bit resolution?

The 7A13 is great for huge amounts of zooming, like looking at pulse tops
or recovery to zero. It recovers from massive overloads instantly, which
most scopes don't do very well.

Which is precisely what I need.

Nowadays I find all-green scopes confusing. And I know that the purple
probe is the purple trace. Nice.

Purple isn't a color that shows up well to me. Those "actinic blue"
fast phosphors that Tek used to offer as an option were absolute torture.
Instant blinding headache.

That should be trace #7, anyway ;=)

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[John Larkin]

On Mon, 08 Mar 2010 08:57:53 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Mon, 08 Mar 2010 07:53:52 -0800, George Herold wrote:

Digital scopes use to have terrible user interfaces. But they are so much
better now. The colored knobs are associated with the trace color. It's
so easy to know which knob to grab... try it you may like it.

If I can find one with better than 500Mhz effective bandwidth, 12 bit or
better resolution and no Windows interface, I'll probably buy one.

Had a rep a while ago trying to sell me one of Tek's offerings. Switched
it on, up came "My Oscilloscope" or some other Windows "My Little Pony"
crap. Switched it off and sent him packing.

They'll be painting them pink, next

Never buy any instrument that has Windows inside!

The only analog scope I still use is our 7104, 1 GHz microchannel
thing. Equivalent digital scopes are way too expensive.

The 11801-series of samplers go to 40 GHz and are cheap nowadays.

John

 

[John Larkin]

On Mon, 08 Mar 2010 08:57:54 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Mon, 08 Mar 2010 08:29:57 -0800, John Larkin wrote:

That's like using two probes in A-B mode. The equivalentcommon-mode rrange
is small, because the internal amps saturate at the equivalent of a couple
of screens worth of offset.

Pretty much what I said.


The TPS can show tou a 10 millivolt signal
riding on the AC line, with 200 MHz bandwidth.

With only 8 bit resolution?

8 bits is pretty good at 10 mV/div riding on 120 RMS. Kick in signal
averaging and you can resolve microvolts.

Signal averaging is magic. Hey, this is 2010!

John

 

[Fred Abse]

On Mon, 08 Mar 2010 10:23:55 -0800, John Larkin wrote:

On Mon, 08 Mar 2010 08:57:53 -0800, Fred Abse
excretatauris@invalid.invalid> wrote:

On Mon, 08 Mar 2010 07:53:52 -0800, George Herold wrote:

Digital scopes use to have terrible user interfaces. But they are so
much better now. The colored knobs are associated with the trace
color. It's so easy to know which knob to grab... try it you may like
it.

If I can find one with better than 500Mhz effective bandwidth, 12 bit or
better resolution and no Windows interface, I'll probably buy one.

Had a rep a while ago trying to sell me one of Tek's offerings. Switched
it on, up came "My Oscilloscope" or some other Windows "My Little Pony"
crap. Switched it off and sent him packing.

They'll be painting them pink, next

Never buy any instrument that has Windows inside!

I never intend to. Hell, I won't buy a PC that has Windows inside !

The only analog scope I still use is our 7104, 1 GHz microchannel thing.
Equivalent digital scopes are way too expensive.

Got one of those, too.

The 11801-series of samplers go to 40 GHz and are cheap nowadays.

I've been thinking about one of those.

John
--

"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[Fred Abse]

On Mon, 08 Mar 2010 10:26:35 -0800, John Larkin wrote:

On Mon, 08 Mar 2010 08:57:54 -0800, Fred Abse
excretatauris@invalid.invalid> wrote:

On Mon, 08 Mar 2010 08:29:57 -0800, John Larkin wrote:

That's like using two probes in A-B mode. The equivalentcommon-mode
rrange is small, because the internal amps saturate at the equivalent
of a couple of screens worth of offset.

Pretty much what I said.


The TPS can show tou a 10 millivolt signal riding on the AC line, with
200 MHz bandwidth.

With only 8 bit resolution?

8 bits is pretty good at 10 mV/div riding on 120 RMS. Kick in signal
averaging and you can resolve microvolts.

Signal averaging is magic. Hey, this is 2010!

I'd still be happier with 12 bits, but then I just don't like digital. I
always feel like I wanna see between the samples ;-)


--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)

 

[George Herold]

On Mar 8, 11:46 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

George Herold wrote:

Michael A. Terrell wrote:

   Good for you.  That would get you fired any place I've ever worked.
If you needed isolation, you plugged whatever you were working on into
an isolation transformer.  If OSHA found a cord like that, the company
would be fined and it could run into thousands of dollars.

Thanks Michael,  The isolation transformer is on order.

   Good deal!  Just don't get careless when using it.

--
Greed is the root of all eBay.

Yeah well Phil A. hasn't answered, but it seems that even with the
scope plugged into an isolation transformer, you can still get
'whacked' if you attach the probe 'ground' to the wrong spot.

George H.

 

[George Herold]

On Mar 8, 11:57 am, Fred Abse <excretatau...@invalid.invalid> wrote:

On Mon, 08 Mar 2010 07:53:52 -0800, George Herold wrote:
Digital scopes use to have terrible user interfaces.  But they are so much
better now.  The colored knobs are associated with the trace color.   It's
so easy to know which knob to grab... try it you may like it.

If I can find one with better than 500Mhz effective bandwidth, 12 bit or
better resolution and no Windows interface, I'll probably buy one.

Had a rep a while ago trying to sell me one of Tek's offerings. Switched
it on, up came "My Oscilloscope" or some other Windows "My Little Pony"
crap. Switched it off and sent him packing.

They'll be painting them pink, next

--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
                                             (Stephen Leacock)

Yeah there is the windows thing. I don't know what you can do about
that. If you are not looking at transient behavior (one shot sort of
stuff.) then the signal averaging on the digital scope is a real
bonus. I used an HP infinium scope at the FEL in Vanderbilt. I think
it did 500MHz, but when you turned it on up popped the windows icon...
ugh, you had to wait while the operating system booted.