Oscilloscope info

[[email protected]]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

thank you
CMOS

 

[Michael A. Terrell]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

thank you
CMOS

Not enough information. What do you want to do with a scope?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Rene Tschaggelar]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

The standalone one will work for 10-15 years,
while the PC based one won't be connectable
anymore in another 10 years.

Rene

 

[Luhan]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

If you really use your scope on a daily basis, a stand alone unit is
much more convenient. It is also the single most useful device for all
design work.

I like my Tektronix TDS 2002, although I have seen some other units
advertized with similar functionality for half the price. Since this
is a once-per-twenty-years purchase, I deciced to go with the known
quantity.

Luhan Monat (luhanxmonat-at-yahoo^dot^com)
http://members.cox.net/berniekm/
"Reality: what a concept!"

 

[Nico Coesel]

The standalone one will work for 10-15 years,
while the PC based one won't be connectable
anymore in another 10 years.

Unless you buy an ethernet based one (don't know if they exist).
Ethernet is very standard and backwards compatible.

 

[Phil Allison]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

** This will get you started.

http://www.dse.com.au/cgi-bin/dse.storefront/44549923019ad2082740c0a87f9c06b8/Product/View/Q1803

Nice and cheap and you get a 10:1 probe chucked in.

If it is not good enough - you had better say why.



........... Phil

 

[Rene Tschaggelar]

Unless you buy an ethernet based one (don't know if they exist).
Ethernet is very standard and backwards compatible.

Ok, the Ethernet connection is to survive.
But the operation would now be with a browser.
They are rather quick in development. So
I'm not too sure whether a browser in 10
years can still talk to the scope.

TCP/IP & UDP ? You wouldn't want that.

Rene

 

[Nico Coesel]

Ok, the Ethernet connection is to survive.
But the operation would now be with a browser.
They are rather quick in development. So
I'm not too sure whether a browser in 10
years can still talk to the scope.

A browser based oscilloscope is going to be a bit slow. A dedicated
application will work though. There is enough software around which is
at least 10 to 20 years old and still works with modern OS versions.

 

[Rich Webb]

If you really use your scope on a daily basis, a stand alone unit is
much more convenient. It is also the single most useful device for all
design work.

I like my Tektronix TDS 2002, although I have seen some other units
advertized with similar functionality for half the price. Since this
is a once-per-twenty-years purchase, I deciced to go with the known
quantity.

I agree with Luhan that the small Teks are great "personal" o'scopes.
Mine is from the prior generation (a TDS 220) that gets pretty regular
use.

 

[Don Lancaster]

hi,
im planning to buy an Oscilloscope for my personel work.
im wondering whether to buy a PC based one or stand akone unit.
any advice on this pls..

thank you
CMOS

As long as the words "HP" or "Agilent" do not appear ANYWHERE on the
oscilloscope, you should be just fine.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[John Larkin]

On Sun, 30 Apr 2006 12:22:15 -0700, Jim Thompson
[snip]

At that point in time Motorola's LM324's had the worst cross-over
distortion, bar none.

...Jim Thompson

Aren't they all the same transistor-level circuit? 324's are class B,
an npn darlington and a pnp following the comp node, *three* junction
drops of crossover. Class B-, at best, class F if I was handing out
grades.

A 324 won't amplify a 60 hz sine wave without visible distortion.

And
don't even *think* about railing one section,

That also depended on brand. Some knew how to do the mirror bias to
prevent crosstalk.

Not National. If one section rails, you get huge (as in volts-level)
spikes out the other three.

Not *any* input... just a *certain* input ;-)

The classic National datasheet has a footnote in 1/2-point type that
hints that weird things happen if any input is pulled below ground.
Something like -0.3 hoses charge all over the chip. Is it only on
certain inputs? This sure burned me a couple of times.

LM339 does the charge-spray thing too. I wonder if anyone has actually
used this "feature" to advantage.

John

 

[Jim Thompson]

Not National. If one section rails, you get huge (as in volts-level)
spikes out the other three.



The classic National datasheet has a footnote in 1/2-point type that
hints that weird things happen if any input is pulled below ground.
Something like -0.3 hoses charge all over the chip. Is it only on
certain inputs? This sure burned me a couple of times.

LM339 does the charge-spray thing too. I wonder if anyone has actually
used this "feature" to advantage.

John

No "spray charge" to it. Depending on input, at about a Vbe below
ground the mirror load on the lateral PNP diff pair saturates. The
positive input, when taken that low, causes the output direction to
reverse.

There is no current limit, so caution with low-Z input sources.

There was a time when I considered the LM324 and the LM339 to be
"God's gift"... used them everywhere. I still like the LM339 if you
don't need high speed.

...Jim Thompson

 

[John Larkin]

No "spray charge" to it. Depending on input, at about a Vbe below
ground the mirror load on the lateral PNP diff pair saturates. The
positive input, when taken that low, causes the output direction to
reverse.

And at higher currents, it will reverse yet again.

But it can trash the other three amps, too!

John

 

[Paul Hovnanian P.E.]

Not enough information. What do you want to do with a scope?

I've got a Tektronics 545 that makes a great space heater. ;-)

 

[Fred Bartoli]

On Sun, 30 Apr 2006 12:22:15 -0700, Jim Thompson
[snip]

At that point in time Motorola's LM324's had the worst cross-over
distortion, bar none.

...Jim Thompson


Aren't they all the same transistor-level circuit? 324's are class B,
an npn darlington and a pnp following the comp node, *three* junction
drops of crossover. Class B-, at best, class F if I was handing out
grades.

A 324 won't amplify a 60 hz sine wave without visible distortion.

And
don't even *think* about railing one section,

That also depended on brand. Some knew how to do the mirror bias to
prevent crosstalk.

Not National. If one section rails, you get huge (as in volts-level)
spikes out the other three.

Not *any* input... just a *certain* input ;-)

The classic National datasheet has a footnote in 1/2-point type that
hints that weird things happen if any input is pulled below ground.
Something like -0.3 hoses charge all over the chip. Is it only on
certain inputs? This sure burned me a couple of times.

LM339 does the charge-spray thing too. I wonder if anyone has actually
used this "feature" to advantage.

Yes to press where it hurts
Once "someone" designed a cpu board without bothering about BUS matching.
Later he told me he didn't _believe_ those stories about TLines.
The net result was an intermittent "software bug" in the CPU UART.
A bit of investigation showed that the UART XTAL oscillator sometime stopped
and slowly resumed a few ms later.
More investigation showed that the databus surrounded the XTAL connections,
and that the oscillator stopped when a high 1 bit count byte was read from
the farmost RAM on the bus. Of course that ram was quite fast and quite far.
Brilliantly "fixed" by the moron by pluging schottky clamps on the most
conveinient place (on a daugther board, right in the middle of the BUS)
where some diodes totalized about 100nH serial parasitics. Then run $50K
worth daughter board with the success you imagine.
Unfortunately the brilliant guy was the irremovable head of the engineering
and design department and lot was to his image.
So I did press as hard as I could... and left.

 

[DJ Delorie]

I've got a Tektronics 545 that makes a great space heater. ;-)

I have a 561A that just takes up space. I replaced it with a 32Ms/s
pc-based parallel port scope.

 

[Michael A. Terrell]

I've got a Tektronics 545 that makes a great space heater. ;-)

No, that's what my old Polarad spectrum analyzer is for, and the fan
noise is to keep you from falling asleep. ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Nico Coesel]

No, that's what my old Polarad spectrum analyzer is for, and the fan
noise is to keep you from falling asleep. ;-)

Duh, my wife could dry her hair with the airflow coming from my
DAS9200 logic analyzer In the winter I install more boards for
better heating. Its 1900VA power supply doesn't care.

 

[Paul Hovnanian P.E.]

No, that's what my old Polarad spectrum analyzer is for, and the fan
noise is to keep you from falling asleep. ;-)

I don't know about that. After a few hours of that dull roaring noise, I
start to think I hear voices embedded in it. Something telling me about
'a hockey mask and an axe', or something like that.

 

[joseph2k]

Why? Their more recent mixed signal oscilloscopes seem fine to me.

Hmmm. Yeah that is about right, they seem have a 1 to 4 year period about
every 20 years when they make decent scopes. They are about due. Too bad
support will go poof altogether too soon.