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LeCroy or Tek scope?

P

Paul Burridge

Jan 1, 1970
0
Correct me if I'm wrong, but didn't you just post a couple of months ago
at which point you had never even heard of Anritsu?

That's right. At which point everyone said Anritsu made great spectrum
analysers - or was it network analysers? No matter. So one assumes
they make great scopes as well. :)
 
J

John Larkin

Jan 1, 1970
0
Aged scope user with recent experience of Tec & LeCroy.
I still prefer CRT analog for analog use, digital scopes still are
"challenged" by the need for a/d that has lots of bits and GHz bw , this
is not easy and the result is noise of 1mV or so on a channel with 10V
max signal.
Anyone disagree?


A tek 7000-series scope (especially a 7104) can do magical things. The
7A22 differential input and the 7A13 diff comparator plugins are
fantastic for working with analog stuff in situations where a digital
scope would only show fuzz.

John
 
J

John Fields

Jan 1, 1970
0
That's right. At which point everyone said Anritsu made great spectrum
analysers - or was it network analysers? No matter. So one assumes
they make great scopes as well. :)
 
N

Nico Coesel

Jan 1, 1970
0
Klaus Bahner said:
It's time for a new scope at work. My budget allows for either a Tek
TDS5054B or a LeCroy Waverunner 6050, however I have a hard time to make
the final decision. Both scopes are certainly very good ones and both
seems to be well suited for my purposes according to their similiar
specs. I do "general" design work with quite different objectives (e.g.
uC, analog, mixed-signal stuff) which does not emphasize a single key
feature, which would make a decision easy. I'm looking more for a
"Jack-of-all-Trade type" scope.
I were able to play with both scopes for half an hour, but this didn't
really help me, because naturally in this time frame you can only
scratch the surface of the feature set or the user interface. Does
anyone like to share his/her comments on those scopes - subjective
opinions are welcome.

One of the important things to look for on a scope is peak-detection.
The LeCroy scope (I think 9000 series) thats at my employer's lab
isn't capable of doing peak detection which means it won't capture
glitches at lower sweep rates. This is a severe limitation.
 
P

PaulCsouls

Jan 1, 1970
0
And the HP wasn't as easy to figure out as the LeCroy, either.


God? Good ol' design?


I had a 500 MHz HP I loved. It was a model just before the changed the
name to Agilent. I demoed one of their hybrid scope, logic analyzers
which I liked and was much simpler to use than those HP linux
analyzers. LeCroy I always found counter intuitive. Ya can't go wrong
with a Tek scope though. They always seem to do what they're supposed
to.

Scope are expensive, demo them. Call some salesmen and try some out.
It's fun.

Paul
 
N

Nico Coesel

Jan 1, 1970
0
Klaus Bahner said:
Agreed! The scope I'm going to buy will replace one from HP, which I
really learned to hate during the recent years :-(

Which model? I'm quite satisfied with the Agilent 54622D.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that PaulCsouls
Scope are expensive, demo them. Call some salesmen and try some out.
It's fun.

The Tek rep that came to see me was 6 ft 8 in tall. Luckily, he believed
me when I explained about budget limitations. (;-)
 
P

Paul Burridge

Jan 1, 1970
0
I have my own reasons for disliking LeCroy, so I can't comment on
their scopes. But I have a TDS5052, and everybody here loves it. The
DPO stuff gives it a very nice "analog scope" feel. Their 1 GHz FET
probes are very nice, too; get them if you can.

The next scope I buy I'd like to have a 1Ghz bandwidth. I'm only
interested in analogue stuff. My current scope is a 50Mhz Tek so it's
quite a jump. Is the design and functionality of a 1Ghz model going to
be fundamentally the same or am I in for an unpleasant surprise and
period of readjustment?
 
J

John Larkin

Jan 1, 1970
0
The next scope I buy I'd like to have a 1Ghz bandwidth. I'm only
interested in analogue stuff. My current scope is a 50Mhz Tek so it's
quite a jump. Is the design and functionality of a 1Ghz model going to
be fundamentally the same or am I in for an unpleasant surprise and
period of readjustment?

Old Tek 7104 (or rackmount 7103) scopes are fairly cheap these days on
ebay. They're 1 GHz analog scopes with microchannel plate CRTs, so you
can see a single sweep in room light at 5 ns/cm or so. They are big,
and take all the very cool 7A-series plugins, which are wonderful for
low-level (audio etc) work too. The only annoyance is the automatic
CRT blanking timer that protects the MCP, but you soon learn to whack
that with your thumb without hardly thinking about it.

7904's (500 MHz, conventional CRT) are nice and even cheaper.

They behave just like any other analog scope, except the 1 GHz plugin
(7A29) is single channel and only has 50 ohm inputs.

John
 
T

Tim Shoppa

Jan 1, 1970
0
Paul Burridge said:
Who/what the hell is LeCroy? Never heard of 'em. :-|

I've been using LeCroy stuff in first NIM bins and then CAMAC crates for a
long time. They are a fairly recent (late 80's? early 90's?) entrant into
the DSO field but they are solidly in the high-end there.

Tim.
 
O

Oliver Betz

Jan 1, 1970
0
Klaus Bahner said:
It's time for a new scope at work. My budget allows for either a Tek
TDS5054B or a LeCroy Waverunner 6050, however I have a hard time to make

In a TDS3012B I found several nasty software bugs, some of them still
existing. For example, under certain circumstances a math result (e.g.
multiplication for power measurement) was scaled *2 or /2 - I don't
remember exactly.

Tektronix was not very cooperative, and tried to tell me that some of
my reports were not a bug, but a feature. Well, the 3012B is "low
cost", maybe error reports of a 5054B are handled better.

I guess that's the problem of most "modern" stuff where "innovation"
is more important than reliability.

Oliver
 
J

Jim Yanik

Jan 1, 1970
0
I had a 500 MHz HP I loved. It was a model just before the changed the
name to Agilent. I demoed one of their hybrid scope, logic analyzers
which I liked and was much simpler to use than those HP linux
analyzers. LeCroy I always found counter intuitive. Ya can't go wrong
with a Tek scope though. They always seem to do what they're supposed
to.

Scope are expensive, demo them. Call some salesmen and try some out.
It's fun.

Paul

When buying a TEK scope,be sure to check out the Long Term Product Support
for that model;last I recall,it was 6 yrs after being dropped from current
production.(which happens very frequently as TEK brings out new models,even
if an "A" version replaces that model.)
But the LTPS periods have been shortening,and may now be even less than 6
yrs.

Once the LTPS period expires,you'll get NO support from TEK except for
calibration,and they don't (or did not) include full schematics in their
"service" manuals.The TDS scopes are intended for module exchange repair
only,and once LTPS expires,that goes away.
Then you're on your own for repairs.
 
J

Jim Yanik

Jan 1, 1970
0
Old Tek 7104 (or rackmount 7103) scopes are fairly cheap these days on
ebay. They're 1 GHz analog scopes with microchannel plate CRTs, so you
can see a single sweep in room light at 5 ns/cm or so. They are big,
and take all the very cool 7A-series plugins, which are wonderful for
low-level (audio etc) work too. The only annoyance is the automatic
CRT blanking timer that protects the MCP, but you soon learn to whack
that with your thumb without hardly thinking about it.

7904's (500 MHz, conventional CRT) are nice and even cheaper.

They behave just like any other analog scope, except the 1 GHz plugin
(7A29) is single channel and only has 50 ohm inputs.

John

The 7904A BW will usually extend out to almost 1 Ghz. with a 7A29 PI.(It's
basically a 7104 without the MCP CRT.)
On any 1Ghz scope,you will need more expensive probes,and connections to
circuits becomes more complicated,if you want to retain the BW and not have
ringing.TEK has a lot of good stuff for this in their scope accessories
pages.
 
J

Jim Yanik

Jan 1, 1970
0
In a TDS3012B I found several nasty software bugs, some of them still
existing. For example, under certain circumstances a math result (e.g.
multiplication for power measurement) was scaled *2 or /2 - I don't
remember exactly.

Tektronix was not very cooperative, and tried to tell me that some of
my reports were not a bug, but a feature. Well, the 3012B is "low
cost", maybe error reports of a 5054B are handled better.

I guess that's the problem of most "modern" stuff where "innovation"
is more important than reliability.

Oliver

TEK service "support" is no longer what it used to be.
They laid off(Rif'd) most of the service support staff several years ago;
"there's no money in it" in their opinion.
 
C

CBarn24050

Jan 1, 1970
0
It's sign of the times and will only get worse. The problem is the boards are
made by machine and tested by computer. Once a product run is over the boards
are no longer repairable so once stocks run out, thats it.
 
G

Guy Macon

Jan 1, 1970
0
CBarn24050 said:
It's sign of the times and will only get worse. The problem is the
boards are made by machine and tested by computer. Once a product
run is over the boards are no longer repairable so once stocks run
out, thats it.

In the long run, it's often cheaper to buy three of something than
to buy one and then, several years later, try to get it fixed.

The problem with doing that is that it assumes that the product
will meet future needs. Computers are an obvious case; by the
time the old one breaks down it's time to upgrade anyway. Scopes
are just the opposite; you will still be measuring waveforms many
years from now.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Guy Macon <[email protected]?.guymacon.com>
In the long run, it's often cheaper to buy three of something than to
buy one and then, several years later, try to get it fixed.

I used to tell people that about vinyl disc records, but hardly anyone
listened, even though you can't 'fix' a damaged vinyl disc.
 
P

Paul Burridge

Jan 1, 1970
0
The 7904A BW will usually extend out to almost 1 Ghz. with a 7A29 PI.(It's
basically a 7104 without the MCP CRT.)
On any 1Ghz scope,you will need more expensive probes,and connections to
circuits becomes more complicated,if you want to retain the BW and not have
ringing.

What causes the false appearance of ringing on a scope trace? Is it
just simply the ground loop created by the earth wire or something
more?
 
B

BFoelsch

Jan 1, 1970
0
Good scopes don't ring, but probes are an art form unto themselves. A good
probe with a long ground wire will ring, a cheap probe will ring even when
grounded directly at the tip.

Once you can view above about 50MHz bandwidth, ANY length of ground (earth)
lead will ring on suitably fast edges. Using an adapter that couples the
ground directly to the tip is the only way to have a chance of seeing what
the circuit is really doing. If you have a poorly designed probe, even that
won't help!

The other big "gotcha" is the probe input impedance. Just for giggles,
calculate the impedance of a 15 pF probe at 100 MHz.

I've been researching and measuring the performance of "commodity" scope
probes with curious results. Some are poor, some aren't bad at all, but I
have yet to find one that truly compares to the Tek probes. Some of the PMK
probes are electrically very good, but the mechanics, features and
construction are awful.

Anybody have a "favorite" brand of passive probe they can suggest?
 
M

maxfoo

Jan 1, 1970
0
Anybody have a "favorite" brand of passive probe they can suggest?

Make your own.

I use a sma-sma dc-block and a ~0.085 semi-rigid coax with an sma connector on
one end. The other end's ground shield is stripped back an 1/8 inch exposing the
center conductor. This is a "RF Sniffer". DC block I use is good up to 18ghz.







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