TDS-1002b Any good? Comments?

[Michael A. Terrell]

John Larkin wrote:

On Tue, 06 Mar 2007 05:20:18 GMT, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:

I'm a collector! I never sell!

I don't have many portable scopes, maybe a Kikusui or two. Mostly big
old mainframes... 535's, 545's, 547's, 7000's, a few HP180's, a few
exotics; a zillion plugins, many sampling. I do have an HP185 4 GHz
sampling scope ca 1961, with plugins and manuals; *that* is a chunk of
history, if an ugly one.

John


Have you considered cleaning the dust of a few items to display in
the lobby, to show the changes in electronics since you started your
business?

Hey, my business isn't that old!

I didn't say it was, but You have been in the electronics business
longer than you've had a business and you have seen a lot of changes,
mostly for the better.

Besides, we don't have a lobby, and seldom have visitors except for
the UPS guy and pizza delivery.

They might enjoy the show. It wouldn't hurt to show examples of your
products (or where possible) a photo showing one of your products in use
in the field, alongside one of your used boards that you've picked up on
Ebay.



BTW, I've been sick in bed for most of a week, and had the power
supply in my computer die. It was a week out of warranty, so I figured I
had nothing to lose. I unpluged all the drives, and it came on, so I
shut it down and reconnected the hard drive. It booted so I am back up
and running. I am running without the CDROM/DVD drive to get on line.
Talk about a design that is too close to the edge.


Did you ever resolve that P.S. problem with Alienware? I would tell
them the whole horrid story is going on your website to warn others
about their customer service, and that as a businesss you bought the
computer to use, not to look at.


--
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

 

[John Larkin]

On Wed, 07 Mar 2007 02:45:04 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

John Larkin wrote:

On Tue, 06 Mar 2007 05:20:18 GMT, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:

I'm a collector! I never sell!

I don't have many portable scopes, maybe a Kikusui or two. Mostly big
old mainframes... 535's, 545's, 547's, 7000's, a few HP180's, a few
exotics; a zillion plugins, many sampling. I do have an HP185 4 GHz
sampling scope ca 1961, with plugins and manuals; *that* is a chunk of
history, if an ugly one.

John


Have you considered cleaning the dust of a few items to display in
the lobby, to show the changes in electronics since you started your
business?

Hey, my business isn't that old!


I didn't say it was, but You have been in the electronics business
longer than you've had a business and you have seen a lot of changes,
mostly for the better.


Besides, we don't have a lobby, and seldom have visitors except for
the UPS guy and pizza delivery.


They might enjoy the show. It wouldn't hurt to show examples of your
products (or where possible) a photo showing one of your products in use
in the field, alongside one of your used boards that you've picked up on
Ebay.



BTW, I've been sick in bed for most of a week, and had the power
supply in my computer die. It was a week out of warranty, so I figured I
had nothing to lose. I unpluged all the drives, and it came on, so I
shut it down and reconnected the hard drive. It booted so I am back up
and running. I am running without the CDROM/DVD drive to get on line.
Talk about a design that is too close to the edge.


Did you ever resolve that P.S. problem with Alienware? I would tell
them the whole horrid story is going on your website to warn others
about their customer service, and that as a businesss you bought the
computer to use, not to look at.

The Alienware thing was a bust. It died after three days. They
promised to overnight a new power supply, and it never showed up. I
sent it back. Quality turned out to be poor (connectors mated poorly,
flimsy sheet metal, tangled wiring, scairy liquid cooling, idiotic
support people) so I guess they've been thoroughly Delled by now.

So I bought an HP server: six hot-plug RAID drive bays, redundant
fans, redundant BIOS, redundant hot-plug power supplies (with separate
line cords), all sorts of spiffy stuff. It's not "authorized" to run
XP, so I got it with no OS and we persuaded a $90 OEM copy of XP to
run. It looks good, so we're going to buy 10 more, so all our PCs are
the same and we'll have a spare or two around. We have an HP sales rep
we can call directly, and *her* boss spoke to us, gave us his phone
number, and says he'll make us a good deal on 10.

And *no* Adobe products will be allowed on our new machines. CutePDF
and Foxit are both free, small, and fast. When I open PDFs with Foxit,
people can't believe it.

John

 

[Anthony Fremont]

John Larkin wrote:

And *no* Adobe products will be allowed on our new machines. CutePDF
and Foxit are both free, small, and fast. When I open PDFs with Foxit,
people can't believe it.

I'm glad someone else sees what junk Adopey puts out. I hope you aren't
allowing any Slumantek bloatware either. I just rescued a machine from
systemworks and internet security. Now it runs like I put in two more CPUs
and another gig of RAM.
;-)

 

[Michael A. Terrell]

John Larkin wrote:

On Wed, 07 Mar 2007 02:45:04 GMT, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:

On Tue, 06 Mar 2007 05:20:18 GMT, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

John Larkin wrote:

I'm a collector! I never sell!

I don't have many portable scopes, maybe a Kikusui or two. Mostly big
old mainframes... 535's, 545's, 547's, 7000's, a few HP180's, a few
exotics; a zillion plugins, many sampling. I do have an HP185 4 GHz
sampling scope ca 1961, with plugins and manuals; *that* is a chunk of
history, if an ugly one.

John


Have you considered cleaning the dust of a few items to display in
the lobby, to show the changes in electronics since you started your
business?

Hey, my business isn't that old!


I didn't say it was, but You have been in the electronics business
longer than you've had a business and you have seen a lot of changes,
mostly for the better.


Besides, we don't have a lobby, and seldom have visitors except for
the UPS guy and pizza delivery.


They might enjoy the show. It wouldn't hurt to show examples of your
products (or where possible) a photo showing one of your products in use
in the field, alongside one of your used boards that you've picked up on
Ebay.



BTW, I've been sick in bed for most of a week, and had the power
supply in my computer die. It was a week out of warranty, so I figured I
had nothing to lose. I unpluged all the drives, and it came on, so I
shut it down and reconnected the hard drive. It booted so I am back up
and running. I am running without the CDROM/DVD drive to get on line.
Talk about a design that is too close to the edge.


Did you ever resolve that P.S. problem with Alienware? I would tell
them the whole horrid story is going on your website to warn others
about their customer service, and that as a businesss you bought the
computer to use, not to look at.

The Alienware thing was a bust. It died after three days. They
promised to overnight a new power supply, and it never showed up. I
sent it back. Quality turned out to be poor (connectors mated poorly,
flimsy sheet metal, tangled wiring, scairy liquid cooling, idiotic
support people) so I guess they've been thoroughly Delled by now.

So I bought an HP server: six hot-plug RAID drive bays, redundant
fans, redundant BIOS, redundant hot-plug power supplies (with separate
line cords), all sorts of spiffy stuff. It's not "authorized" to run
XP, so I got it with no OS and we persuaded a $90 OEM copy of XP to
run. It looks good, so we're going to buy 10 more, so all our PCs are
the same and we'll have a spare or two around. We have an HP sales rep
we can call directly, and *her* boss spoke to us, gave us his phone
number, and says he'll make us a good deal on 10.

And *no* Adobe products will be allowed on our new machines. CutePDF
and Foxit are both free, small, and fast. When I open PDFs with Foxit,
people can't believe it.

John

Glad to hear that you got it resolved. Identical machines make it
easier to track down those software/ hardware problems, too. Identical
configuration makes it easy to move between work stations, and spares.
The biggest killer I see on business computers is from dust, where they
are under the desk. Every step stirs up loose dust, and the cooling
fans suck it into the case. Some have over 1/4" of dust in the bottom of
the cabinet, and have mild corrosion where the dust and humidity react
with the plating.


--
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]

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

And *no* Adobe products will be allowed on our new machines. CutePDF
and Foxit are both free, small, and fast. When I open PDFs with Foxit,
people can't believe it.

Hmm, gonna try that. My 'boss' and I are still in a contest who can
curse loudest while using Acrobat reader. The winner has not been
decided yet.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

 

The 2K memory is pretty aweful these days, most USB analysers have a
lot more - shop around.
Deep memory is particually important for digital design.

You missed a pretty significant point here. The Intronix unit (
http://www.pctestinstruments.com ) has "real-time sample
compression" (aka transitional sampling) which greatly extends its
useful buffer depth. I've been using mine for about a year now, and am
amazed at what it's been able to pack into that "2k" buffer. Sometimes
it captures literally millions of samples.

I shopped around quite a bit before I chose the Intronix product.
There are several USB analyzers in this price range with more memory,
but all sacrifice something in exchange for it. They either have much
slower sample rates, less sophisticated triggering or a lot fewer
channels. Some of them have pretty pathetic input characteristics as
well. I saw one which claimed to sample at 500MHz, but only had a
50MHz bandwidth??? - pretty useless for modern digital signals. Input
capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! The Intronix unit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

Advanced trigger features are particularly important for digital
analysis were the data stream tends not to be repetitive and can
literally go on forever. In fact, I'd challenge anyone in a "deep
buffer" versus "sophisticated trigger" contest. An appropriate trigger
setup can capture data which no amount of buffer depth could find. For
example, an intermittent problem which takes hours/days to occur. How
much memory would it take to capture the entire period and then search
back through it for the problem? When set properly, sophisticated
trigger features allow an analyzer to monitor signals for days,
allowing it to capture just that eureka moment ;-)

Jim

 

[Anthony Fremont]

jmb101@qwest.net wrote:

The 2K memory is pretty aweful these days, most USB analysers have a
lot more - shop around.
Deep memory is particually important for digital design.

You missed a pretty significant point here. The Intronix unit (
http://www.pctestinstruments.com ) has "real-time sample
compression" (aka transitional sampling) which greatly extends its
useful buffer depth. I've been using mine for about a year now, and am
amazed at what it's been able to pack into that "2k" buffer. Sometimes
it captures literally millions of samples.

Millions?

I shopped around quite a bit before I chose the Intronix product.
There are several USB analyzers in this price range with more memory,
but all sacrifice something in exchange for it. They either have much
slower sample rates, less sophisticated triggering or a lot fewer
channels. Some of them have pretty pathetic input characteristics as
well. I saw one which claimed to sample at 500MHz, but only had a
50MHz bandwidth??? - pretty useless for modern digital signals. Input
capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! The Intronix unit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

I've looked at a bunch of stuff, and I think I'm going to get one of these
fairly soon. One thing I do think they could improve upon IIRC is the speed
over the USB link.

Advanced trigger features are particularly important for digital
analysis were the data stream tends not to be repetitive and can
literally go on forever. In fact, I'd challenge anyone in a "deep
buffer" versus "sophisticated trigger" contest. An appropriate trigger

And yet another reason that I really liked this one.

setup can capture data which no amount of buffer depth could find. For
example, an intermittent problem which takes hours/days to occur. How
much memory would it take to capture the entire period and then search
back through it for the problem? When set properly, sophisticated
trigger features allow an analyzer to monitor signals for days,
allowing it to capture just that eureka moment ;-)

The data analysis/decoding is another big plus for the LogicPort. I could
really make use of that.

I see them on e-bay for $10 off the normal price, but I'm holding out for a
better deal. ;-)

 

[David L. Jones]

On Mar 27, 9:39 pm, jmb...@qwest.net wrote:

The 2K memory is pretty aweful these days, most USB analysers have a
lot more - shop around.
Deep memory is particually important for digital design.

You missed a pretty significant point here. The Intronix unit (http://www.pctestinstruments.com) has "real-time sample
compression" (aka transitional sampling) which greatly extends its
useful buffer depth. I've been using mine for about a year now, and am
amazed at what it's been able to pack into that "2k" buffer. Sometimes
it captures literally millions of samples.

Oops, I didn't see that it used transitional sampling.
Transitional sampling is good, but it's no substitute for a good deep
memory. Transitional memory is only as good as the number of samples
captured by the highest frequency (most transitional changes) signal
being captured. i.e no point having one channel only changing slowing
if the other one changes fast and uses up all the memory. Of course,
you can also have transitional memory on a per channel basis too, but
then you don't get to see the other channel data that have already had
their memory used up.

I shopped around quite a bit before I chose the Intronix product.
There are several USB analyzers in this price range with more memory,
but all sacrifice something in exchange for it. They either have much
slower sample rates, less sophisticated triggering or a lot fewer
channels. Some of them have pretty pathetic input characteristics as
well. I saw one which claimed to sample at 500MHz, but only had a
50MHz bandwidth??? - pretty useless for modern digital signals. Input
capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! The Intronix unit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

That's what buffer probes are for, you can make your own low
capacitance probes for any logic analyser if you need too.

Advanced trigger features are particularly important for digital
analysis were the data stream tends not to be repetitive and can
literally go on forever. In fact, I'd challenge anyone in a "deep
buffer" versus "sophisticated trigger" contest.

Of course, good trigger features are essential for any logic analyser.
Stuff like serial data decoding and sequencing is invaluable for
instance.

An appropriate trigger
setup can capture data which no amount of buffer depth could find. For
example, an intermittent problem which takes hours/days to occur. How
much memory would it take to capture the entire period and then search
back through it for the problem?

No one uses a logic analyser like that, you *always* use smart
triggering, that's not what big memory is for. Big memory allows you
to capture *detail* at the trigger point and also *detail* much
further back or forward in the signal. Transitional sampling can't do
this.

When set properly, sophisticated
trigger features allow an analyzer to monitor signals for days,
allowing it to capture just that eureka moment ;-)

Yep, that's the idea with *any* logic analyser. Goos logic analysers
need comprehensive trigger features *and* big memory.

Dave.

 

Oops, I didn't see that it used transitional sampling.
Transitional sampling is good, but it's no substitute for a good deep
memory.

Both techniques have pros and cons but without transtitional sampling,
even 1 or 2 megasamples of "good deep memory" gets filled in a hurry.
I have an Agilent 54622D sitting on my bench along side the Intronix
unit. The Agilent unit has 2 meg of memory, but doesn't have
transitional sampling. When I need to do pure logic analysis, I find
myself reaching for the Intronix unit first. Mostly because it has
more channels and more speed (you can never have enough of either).
I've also become partial to PC-based instruments because I can view
the signals on a 21" monitor instead of a tiny 6" screen. It's also
very nice to use a mouse and full sized keyboard for setup. Naming
signals on the Agilent unit is very tedious - one character at a time,
scrolling through the whole alphabet to enter each character. I use
the Agilent only when I need mixed signal analysis (or just a digital
scope).

capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! TheIntronixunit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

That's what buffer probes are for, you can make your own low
capacitance probes for any logic analyser if you need too.

You must be joking. You're going to buy a logic analyzer and then have
to turn around and build/buy an input buffer to get it to work
adequately? Any buffer will add skew and potentially noise or other
signal fidelity issues which can greatly degrade its high-speed
capability. This characteristic is the manufacturer's responsibility.
I wasn't shopping for a kit.

An appropriate trigger
setup can capture data which no amount of buffer depth could find. For
example, an intermittent problem which takes hours/days to occur. How
much memory would it take to capture the entire period and then search
back through it for the problem?

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it. That's the whole point. Many analyzers in
this price range have very limited trigger capability. If you assume
that all are created equal, you will be very disappointed. That "deep
buffer" unit might not look so great when you discover that its
trigger capability is no more sophisticated than an average data
logger (that describes several products on the market).

When set properly, sophisticated
trigger features allow an analyzer to monitor signals for days,
allowing it to capture just that eureka moment ;-)

Yep, that's the idea with *any* logic analyser. Goos logic analysers
need comprehensive trigger features *and* big memory.

No, not *any* logic analyzer, because not all of them have that
capability. As I said before, give me sophisticated triggering, and
I'll take on any buffer depth ;-)

Jim

 

[David L. Jones]

On Mar 28, 7:34 pm, jmb...@qwest.net wrote:

Oops, I didn't see that it used transitional sampling.
Transitional sampling is good, but it's no substitute for a good deep
memory.

Both techniques have pros and cons but without transtitional sampling,
even 1 or 2 megasamples of "good deep memory" gets filled in a hurry.

It can, but you missed my point about the limitations of transitional
sampling, it is no substitute for a large deep memory. The best logic
analyser would have a combination of transitional sampling and a big
memory.

I have an Agilent 54622D sitting on my bench along side the Intronix
unit. The Agilent unit has 2 meg of memory, but doesn't have
transitional sampling. When I need to do pure logic analysis, I find
myself reaching for the Intronix unit first. Mostly because it has
more channels and more speed (you can never have enough of either).
I've also become partial to PC-based instruments because I can view
the signals on a 21" monitor instead of a tiny 6" screen. It's also
very nice to use a mouse and full sized keyboard for setup. Naming
signals on the Agilent unit is very tedious - one character at a time,
scrolling through the whole alphabet to enter each character. I use
the Agilent only when I need mixed signal analysis (or just a digital
scope).

I can hook an external large screen LCD monitor up to my Aligent mixed
signal scope, very nice.
Yes, the single digit name setup is a pain, but for my use the
portability of a standlone logic analyser is usually more important.
Each to there own, but a PC based logic analyser aren't a bad
compromise.

capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! TheIntronixunit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

That's what buffer probes are for, you can make your own low
capacitance probes for any logic analyser if you need too.

You must be joking. You're going to buy a logic analyzer and then have
to turn around and build/buy an input buffer to get it to work
adequately? Any buffer will add skew and potentially noise or other
signal fidelity issues which can greatly degrade its high-speed
capability. This characteristic is the manufacturer's responsibility.
I wasn't shopping for a kit.

Skew is not an issue if all the signals are buffered equally including
the clocks. Most good logic analysers come with external buffered
probes, otherwise you are going to have some mighty short test
leads ...

An appropriate trigger
setup can capture data which no amount of buffer depth could find. For
example, an intermittent problem which takes hours/days to occur. How
much memory would it take to capture the entire period and then search
back through it for the problem?

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it.

All logic analysers have at least the basics, word pattern matching
and don't care states across all channels for instance. Good enough
for most general use.

That's the whole point. Many analyzers in
this price range have very limited trigger capability. If you assume
that all are created equal, you will be very disappointed. That "deep
buffer" unit might not look so great when you discover that its
trigger capability is no more sophisticated than an average data
logger (that describes several products on the market).

Depends entirely on your requirements. I personally find that for my
use the deep memory and basic triggering is more important than
transitional sampling, e.g. to see detail separated by large idol
periods. No amount of fancy triggering and transitional sampling will
let you do that. A tranistional sampling analyser with a small memory
would be useless for many of my recent applications.

When set properly, sophisticated
trigger features allow an analyzer to monitor signals for days,
allowing it to capture just that eureka moment ;-)

Yep, that's the idea with *any* logic analyser. Goos logic analysers
need comprehensive trigger features *and* big memory.

No, not *any* logic analyzer, because not all of them have that
capability. As I said before, give me sophisticated triggering, and
I'll take on any buffer depth ;-)

Once again, depends on the application. But transitional sampling is
*no substitue* for deep memory, it has a few important limitations
which you failed to comment on.

Dave.

 

[David L. Jones]

On Mar 29, 11:45 am, "David L. Jones" <altz...@gmail.com> wrote:

On Mar 28, 7:34 pm, jmb...@qwest.net wrote:

Oops, I didn't see that it used transitional sampling.
Transitional sampling is good, but it's no substitute for a good deep
memory.

Both techniques have pros and cons but without transtitional sampling,
even 1 or 2 megasamples of "good deep memory" gets filled in a hurry.

It can, but you missed my point about the limitations of transitional
sampling, it is no substitute for a large deep memory. The best logic
analyser would have a combination of transitional sampling and a big
memory.

I have an Agilent 54622D sitting on my bench along side the Intronix
unit. The Agilent unit has 2 meg of memory, but doesn't have
transitional sampling. When I need to do pure logic analysis, I find
myself reaching for the Intronix unit first. Mostly because it has
more channels and more speed (you can never have enough of either).
I've also become partial to PC-based instruments because I can view
the signals on a 21" monitor instead of a tiny 6" screen. It's also
very nice to use a mouse and full sized keyboard for setup. Naming
signals on the Agilent unit is very tedious - one character at a time,
scrolling through the whole alphabet to enter each character. I use
the Agilent only when I need mixed signal analysis (or just a digital
scope).

I can hook an external large screen LCD monitor up to my Aligent mixed
signal scope, very nice.
Yes, the single digit name setup is a pain, but for my use the
portability of a standlone logic analyser is usually more important.
Each to there own, but a PC based logic analyser aren't a bad
compromise.

capacitance is another area to watch out for. Some inexpensive
analyzers are in the 10-15pF range. That will cause significant
loading on digital signals. The analyzer unfortunately becomes part of
the circuit! TheIntronixunit's inputs are 5pF which is the lowest
I've seen short of Agilent/Tek.

That's what buffer probes are for, you can make your own low
capacitance probes for any logic analyser if you need too.

You must be joking. You're going to buy a logic analyzer and then have
to turn around and build/buy an input buffer to get it to work
adequately? Any buffer will add skew and potentially noise or other
signal fidelity issues which can greatly degrade its high-speed
capability. This characteristic is the manufacturer's responsibility.
I wasn't shopping for a kit.

Skew is not an issue if all the signals are buffered equally including
the clocks. Most good logic analysers come with external buffered
probes, otherwise you are going to have some mighty short test
leads ...

Just realised that isn't an issue with the Intronix unit due to it's
small size, just move the whole unit close to your circuit.

BTW, I was saying you'd only make your own probes if you really needed
too. Usually you buy them of course.

Dave.

 

It can, but you missed my point about the limitations of transitional
sampling, it is no substitute for a large deep memory.

I never said it was a 100% substitute. I said that it extends the
capability significantly. I also said that given the choice of deeper
memory or more sophisticated trigger features I would (and in fact
did) choose the trigger features. The Intronix unit had the best of
any I could find, along with transitional sampling and other nice
features.

The best logic
analyser would have a combination of transitional sampling and a big
memory.

And it would also have a rich set of trigger features. But you will
not find that "ultimate" logic analyzer in the sub $1000 range. In
that price range you will have to compromise. I thought that was what
this discussion was about - picking the right mix of features within a
given budget. If you have an unlimited budget, then this whole thread
is meaningless to you.

I can hook an external large screen LCD monitor up to my Aligent mixed
signal scope, very nice.

The $5000 Agilent 54622D won't do that.

Yes, the single digit name setup is a pain, but for my use the
portability of a standlone logic analyser is usually more important.
Each to there own, but a PC based logic analyser aren't a bad
compromise.

A stand alone unit is much less portable than a typical PC-based unit
(the 3 ounce Intronix analyzer for example). When I'm doing digital
work - which is almost always, I of course have a PC nearby. What else
would I be using to develop the software/logic I'm debugging? Moving a
PC-based analyzer from PC to PC seems to me like much less work than
lugging around a 20 pound "portable" stand alone unit. It also fits
nicely in my laptop bag for field work.

Skew is not an issue if all the signals are buffered equally including
the clocks.

If only that were possible. Anything you can use to buffer a signal
has delay. Delay between multiple buffer channels will not be equal.
With a lot of effort you can make them very close to equal, but again
why bother? Just choose a properly designed analyzer to begin with,
and it's no issue.

By the way, you keep mentioning an off-the-shelf "buffer probe" which
you would buy rather than having to build one. Could you give me the
model / brand? I'd like to have a look at that.

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it.

All logic analysers have at least the basics, word pattern matching
and don't care states across all channels for instance. Good enough
for most general use.

"the basics" /= "smart triggering"

If you believe that basic word pattern recognition constitutes
sophisticated triggering, then I understand why you rely so much on
deep memory. I will agree that deeper memory is sometimes a reasonable
substitute for deeper thought.

Depends entirely on your requirements. I personally find that for my
use the deep memory and basic triggering is more important than
transitional sampling, e.g. to see detail separated by large idol
periods. No amount of fancy triggering and transitional sampling will
let you do that. A tranistional sampling analyser with a small memory
would be useless for many of my recent applications.

You have described the ideal scenario for transitional sampling.
Specifically, "detail separated by idol periods". That situation gives
the greatest compression possible. Have you ever actually seen
transitional sampling in use? It sounds like you haven't. Take a look
at the Intronix website (under screenshots / sample compression). They
have an example showing about 10 megasamples of data captured in the
"2k" buffer. As a more extreme example, I have personally sampled
several seconds worth of serial traffic separated by idol time, all in
a single acquisition with 5ns resolution. That's hundereds of millions
of samples. Will it always do that? No of course not. Can your deep
memory Agilent unit do that? Not a chance unless it has transitional
sampling.

Jim

 

[David L. Jones]

On Mar 29, 3:27 pm, jmb...@qwest.net wrote:

It can, but you missed my point about the limitations of transitional
sampling, it is no substitute for a large deep memory.

I never said it was a 100% substitute. I said that it extends the
capability significantly. I also said that given the choice of deeper
memory or more sophisticated trigger features I would (and in fact
did) choose the trigger features. The Intronix unit had the best of
any I could find, along with transitional sampling and other nice
features.

Sure, it's all a matter of what features set you need for what price.
I'm not bagging the Intronix unit, it looks like quite a capable unit.

I can hook an external large screen LCD monitor up to my Aligent mixed
signal scope, very nice.

The $5000 Agilent 54622D won't do that.

The 54620 series has been replaced by the newer 6000 series, at a
similar price level. I have one of each. I thought the 54600 series
was excellent, but the 6000 is so much better. I still use both
though.
They could use some more advanced trigger features on the logic
analyser thoush, but considering it's just got a logic analyser tacked
on, it's very useful.

Yes, the single digit name setup is a pain, but for my use the
portability of a standlone logic analyser is usually more important.
Each to there own, but a PC based logic analyser aren't a bad
compromise.

A stand alone unit is much less portable than a typical PC-based unit
(the 3 ounce Intronix analyzer for example). When I'm doing digital
work - which is almost always, I of course have a PC nearby. What else
would I be using to develop the software/logic I'm debugging? Moving a
PC-based analyzer from PC to PC seems to me like much less work than
lugging around a 20 pound "portable" stand alone unit. It also fits
nicely in my laptop bag for field work.

Once again, horses for courses, depends on what you are working on.
For me, I don't particually like PC based instruments, I can't always
bring things to the bench near a PC. I also don't trust the PC to stay
up for a week if I'm waiting for an elusive trigger signal.

Skew is not an issue if all the signals are buffered equally including
the clocks.

If only that were possible. Anything you can use to buffer a signal
has delay. Delay between multiple buffer channels will not be equal.
With a lot of effort you can make them very close to equal, but again
why bother? Just choose a properly designed analyzer to begin with,
and it's no issue.

Of course, I'm just pointing out that that it *is* possible to make
your own probes if you need super-duper low capacitance or whatever
for a specific application. Just like it's not uncommon to roll your
own scope probes, but digital ones are not as easy of course.

By the way, you keep mentioning an off-the-shelf "buffer probe" which
you would buy rather than having to build one. Could you give me the
model / brand? I'd like to have a look at that.

There really are no "generic" ones, either the manufacturer offers a
range of suitable probes or they don't offer them. The Agilent 54600
and 6000 series MSO's come with very nice buffered probes.

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it.

All logic analysers have at least the basics, word pattern matching
and don't care states across all channels for instance. Good enough
for most general use.

"the basics" /= "smart triggering"

I did not mean imply it was.

If you believe that basic word pattern recognition constitutes
sophisticated triggering, then I understand why you rely so much on
deep memory.

I don't think that, I was just pointing out that all logic analyser
come with basic triggering and often that is suitable for most
purposes for most people. If you need more complex triggering then you
need it, simple as that.

Depends entirely on your requirements. I personally find that for my
use the deep memory and basic triggering is more important than
transitional sampling, e.g. to see detail separated by large idol
periods. No amount of fancy triggering and transitional sampling will
let you do that. A tranistional sampling analyser with a small memory
would be useless for many of my recent applications.

You have described the ideal scenario for transitional sampling.
Specifically, "detail separated by idol periods". That situation gives
the greatest compression possible.

I know that is the ideal scenario for transitional sampling, but in
the case of the Intronix unit we are talking about it only has 2K
points of memory. My needs often call for capturing say thousands of
cycles, waiting a period, capturing a few more thousand, and repeat XX
times. In this case the 2K points of memory on the Intronix unit would
make make it useless for this task. That does not mean it's bad unit,
it's just unsuited to some tasks I do. For some tasks I just have to
drag out the $XX,XXX logic analyser, but it seems the more you pay the
harder they are to drive!

Have you ever actually seen
transitional sampling in use? It sounds like you haven't.

I've done more than that, I've designed one, thanks.

Take a look
at the Intronix website (under screenshots / sample compression). They
have an example showing about 10 megasamples of data captured in the
"2k" buffer. As a more extreme example, I have personally sampled
several seconds worth of serial traffic separated by idol time, all in
a single acquisition with 5ns resolution. That's hundereds of millions
of samples. Will it always do that? No of course not. Can your deep
memory Agilent unit do that? Not a chance unless it has transitional
sampling.

Can the Intronix unit capture more than 2K transitions? No.
Horses for courses.

Deep memory is good.
Transitional sampling is good.
Complex triggering is good.

Dave.

 

By the way, you keep mentioning an off-the-shelf "buffer probe" which
you would buy rather than having to build one. Could you give me the
model / brand? I'd like to have a look at that.

There really are no "generic" ones, either the manufacturer offers a
range of suitable probes or they don't offer them. The Agilent 54600
and 6000 series MSO's come with very nice buffered probes.

Oh so now you've changed your mind. Previously I pointed out that many
of the PC-based units had excessively high input capacitance. You
mentioned twice that a "buffer probe" would solve that problem, and
that rather than build one "Usually you buy them of course". Now
you're saying that only the manufacturer can supply them. None of the
PC-based manufacturers actually do offer them - so you are on your
own. I'll restate my original point: Be sure to take a close look at
input capacitance when choosing a PC-based logic analyzer. Some of
them are excessively high, and this will cause you grief.

By the way, the probes which come with the Agilent 54600 and 6000
series *do not* contain any buffers. They are completely passive, with
no acitive circuitry at all in the probe itself. I would have expected
an expert like yourself to know that.

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it.

All logic analysers have at least the basics, word pattern matching
and don't care states across all channels for instance. Good enough
for most general use.

I don't think that, I was just pointing out that all logic analyser
come with basic triggering and often that is suitable for most
purposes for most people. If you need more complex triggering then you
need it, simple as that.

Previously you said that "No one uses a logic analyser like that, you
*always* use smart triggering". Now you're saying that you use basic
(non smart?) triggering for most purposes. You sure change your mind a
lot. I wouldn't expect that from an expert.

Have you ever actually seen
transitional sampling in use? It sounds like you haven't.

I've done more than that, I've designed one, thanks.

Please tell us more. With your vast knowledge I',m sure you've
designed a great analyzer. How much does it cost? Where can we buy
it?

Can the Intronix unit capture more than 2K transitions? No.
Horses for courses.

Never claimed it could. Most of the analyzers I've used over the past
25 years had 2k of memory or less, and none before the Intronix unit
had transitional sampling. Yet, these analzyers have always enabled me
to debug my designs. And by the way, I'm not the only one. Every
digital design before 1993 was debugged with analyzers having 2k or
less. That includes the original IBM PC/AT, the Cray I super computer,
every piece of hardware put into space, and every product with an
embedded processor. So be careful when you throw around words like
"useless". You make yourself look dim.

Deep memory is good.
Transitional sampling is good.
Complex triggering is good.

Yes, all of those things are good, but you won't find them all in a
sub $1000 PC-based logic analyzer. Spending $XX,XXX on a logic
analyzer (and then bragging about it) is not the right solution for
everyone.

Jim

 

[David L. Jones]

On Mar 30, 6:07 am, goo...@pctestinstruments.com wrote:

By the way, you keep mentioning an off-the-shelf "buffer probe" which
you would buy rather than having to build one. Could you give me the
model / brand? I'd like to have a look at that.

There really are no "generic" ones, either the manufacturer offers a
range of suitable probes or they don't offer them. The Agilent 54600
and 6000 series MSO's come with very nice buffered probes.

Oh so now you've changed your mind. Previously I pointed out that many
of the PC-based units had excessively high input capacitance. You
mentioned twice that a "buffer probe" would solve that problem, and
that rather than build one "Usually you buy them of course". Now
you're saying that only the manufacturer can supply them. None of the
PC-based manufacturers actually do offer them - so you are on your
own.

If none of the PC based scope manufacturers offer them then you
obviously don't have a choice. In which case be careful in what you
buy up front or be prepared to make your own probes if needed.

I'll restate my original point:
Be sure to take a close look at
input capacitance when choosing a PC-based logic analyzer. Some of
them are excessively high, and this will cause you grief.

I am not doubting your original post, yes it is an important point.

By the way, the probes which come with the Agilent 54600 and 6000
series *do not* contain any buffers. They are completely passive, with
no acitive circuitry at all in the probe itself. I would have expected
an expert like yourself to know that.

I could have sworn I opened the 54600 series probe box once and it had
some active circuitry, but that was long time ago, so ok, my mistake,
sorry. I may have been confused with another LA, I've used a lot of
them.

No one uses a logic analyser like that, you *always* use smart
triggering,

*Not* if you don't have it.

All logic analysers have at least the basics, word pattern matching
and don't care states across all channels for instance. Good enough
for most general use.

I don't think that, I was just pointing out that all logic analyser
come with basic triggering and often that is suitable for most
purposes for most people. If you need more complex triggering then you
need it, simple as that.

Previously you said that "No one uses a logic analyser like that, you
*always* use smart triggering". Now you're saying that you use basic
(non smart?) triggering for most purposes. You sure change your mind a
lot. I wouldn't expect that from an expert.

You have misinterpreted what I said again.
What was I was referring to was your inference that I simply hit the
trigger button and was relying on the deep buffer of the scope, but of
course no one uses a logic analyser like that (that I know of), they
always use some form of minimal triggering to find the event they want
and then get any required pre and post data.
Sorry, the word "smart" probably wasn't too appropriate there, I
should have said "standard" or something that would not confuse you.

Have you ever actually seen
transitional sampling in use? It sounds like you haven't.

I've done more than that, I've designed one, thanks.

Please tell us more. With your vast knowledge I',m sure you've
designed a great analyzer. How much does it cost? Where can we buy
it?

It was a follow up design to my 40MHz 32 channel PC based logic
analyser published in Electronics Australia in Oct/Nov 96, but it
never made it to publication, sorry to disappoint you.

Can the Intronix unit capture more than 2K transitions? No.
Horses for courses.

Never claimed it could. Most of the analyzers I've used over the past
25 years had 2k of memory or less, and none before the Intronix unit
had transitional sampling. Yet, these analzyers have always enabled me
to debug my designs.

Well that's just fantastic for you, and that's all I need *most* of
the time too. But recently (and at other times) such a logic logic
analyser would be essentially useful for me.

And by the way, I'm not the only one. Every
digital design before 1993 was debugged with analyzers having 2k or
less. That includes the original IBM PC/AT, the Cray I super computer,
every piece of hardware put into space, and every product with an
embedded processor. So be careful when you throw around words like
"useless". You make yourself look dim.

What is your problem Jim?, I was just pointing out that I've had to
use (many times) a logic analyser much more powerful and with much
more sample memory than the 2K (transitions or otherwise), it does
happen you know, that's why they make bigger and better logic
analysers.
If a logic analyser does not let me see what I want to see because
it's got a small memory, then it's essentially "useless" for my task
at that time. But if that's all you got, then, well, you make do with
it some how.

Deep memory is good.
Transitional sampling is good.
Complex triggering is good.

Yes, all of those things are good, but you won't find them all in a
sub $1000 PC-based logic analyzer.

I never said you could.

Spending $XX,XXX on a logic
analyzer (and then bragging about it) is not the right solution for
everyone.

I never said it was! and I was not bragging, just pointing out that
I've had to resort to such high end logic analysers on quite a few
occasions.

Chill out a bit, I'm not out to get you, or to bag the Intronix unit,
really.

Dave.

 

[David L. Jones]

On Mar 30, 6:07 am, goo...@pctestinstruments.com wrote:

Ah, judging by your newly displayed email address you either work for
Intronix or you *are* Intronix, in which case that explains why you
have such a bee in your bonnet! ;-)

Dave.

 

Ah, judging by your newly displayed email address you either work for
Intronix or you *are* Intronix, in which case that explains why you
have such a bee in your bonnet! ;-)

Well, your close. I'm not Intronix, and I don't work for anyone. I'm
retired. You may have already guessed this by the fact that I was
using logic analyzers 25 years ago.

With regards to my connection to Intronix, I started out as just an
enthusiastic customer/user of the their product. I became friendly
with, and have had many conversations with the designer of the
product. For a short while we even had an arangement where I was
<gasp> paid to do some of their tech-support (before they hired
someone to do it full time). That's one reason I'm so intimently
familiar with the product. And yes, I do still have certain privelages
with the company - including email.

I came across this thread while looking for feedback on the Tektronix
TDS1002B. I'm a bit of a test-equipment junky, and I saw a TDS1002B
for sale cheap. I was considering buying it, though obviously won't
after reading what users have said about them here.

When I saw a blow-hard self-appointed expert like yourself condemn a
product which you hadn't even tried, one which I happen to know very
well and am very impressed with, I couldn't resist taking you on. In
the brief period that I did tech support for Intronix I talked to many
happy users of their product. I was amazed at just how loyal people
are to it. Some large companies have actually purchased dozens of
them. There is something about the product which people seem to fall
in love with. It's friendly to use and all of that, but I think the
real reason might just be that for once, a PC-based test instrument
meets its specs, and actually does what it says it will. My
observation in the past has been that many don't.

Please tell us more. With your vast knowledge I',m sure you've
designed a great analyzer. How much does it cost? Where can we buy
it?

It was a follow up design to my 40MHz 32 channel PC based logic
analyser published in Electronics Australia in Oct/Nov 96, but it
never made it to publication, sorry to disappoint you.

So now you know where I'm coming from, but you've also revealed your
motivation. In a word, it's jealousy. You *almost* did something
meaningful 10 years ago, but you didn't have the where-with-all to put
anything into production so you put it into the public domain instead.
Now you resent anyone who has had commercial success in that market. I
could tell from your comments that you just couldn't stand the thought
of another soul buying that product. Darn the people at Intronix
anyhow for following through on their efforts, and for being
successful!

Don't feel bad though. I don't have the where-with-all to put anything
into that market either. But I don't resent those who have.

So you can let the bee out of *your* bonnet now ;-}

Jim

 

[David L. Jones]

On Mar 30, 12:24 pm, goo...@pctestinstruments.com wrote:

Ah, judging by your newly displayed email address you either work for
Intronix or you *are* Intronix, in which case that explains why you
have such a bee in your bonnet! ;-)

Well, your close. I'm not Intronix, and I don't work for anyone. I'm
retired. You may have already guessed this by the fact that I was
using logic analyzers 25 years ago.

Nope, didn't guess, sorry. I used my first logic analyser 20+ years
ago now, and I am nowhere near retirement age, probably got another 30
years to go in fact.

With regards to my connection to Intronix, I started out as just an
enthusiastic customer/user of the their product. I became friendly
with, and have had many conversations with the designer of the
product. For a short while we even had an arangement where I was
gasp> paid to do some of their tech-support (before they hired
someone to do it full time). That's one reason I'm so intimently
familiar with the product. And yes, I do still have certain privelages
with the company - including email.

Ok, cool.

When I saw a blow-hard self-appointed expert like yourself condemn a
product which you hadn't even tried, one which I happen to know very
well and am very impressed with, I couldn't resist taking you on.

And you kept up all the chest-beating after I admitted I hadn't
noticed the Intronix unit used transitional sampling, which of course
puts it into an entirely better and more useful category, and I said
as much. And I have said at least a few times that I am not bagging
the Intronix unit.

In the brief period that I did tech support for Intronix I talked to many
happy users of their product. I was amazed at just how loyal people
are to it. Some large companies have actually purchased dozens of
them. There is something about the product which people seem to fall
in love with. It's friendly to use and all of that, but I think the
real reason might just be that for once, a PC-based test instrument
meets its specs, and actually does what it says it will. My
observation in the past has been that many don't.

Very true, many don't.

Please tell us more. With your vast knowledge I',m sure you've
designed a great analyzer. How much does it cost? Where can we buy
it?

It was a follow up design to my 40MHz 32 channel PC based logic
analyser published in Electronics Australia in Oct/Nov 96, but it
never made it to publication, sorry to disappoint you.

So now you know where I'm coming from, but you've also revealed your
motivation. In a word, it's jealousy.

Nope, you couldn't be further from the truth.

You *almost* did something
meaningful 10 years ago, but you didn't have the where-with-all to put
anything into production so you put it into the public domain instead.

Nope, you couldn't be further from the truth again.
I never had any ideas of turning it into a commercial product, it did
it just for fun like I did with all my published projects (almost a
dozen of them), it's one of my hobbies.

Now you resent anyone who has had commercial success in that market. I
could tell from your comments that you just couldn't stand the thought
of another soul buying that product. Darn the people at Intronix
anyhow for following through on their efforts, and for being
successful!

Utter mis-interpreted rubbish again.
I based my original post on the (incorrect) point that it only had 2K
(of non-transitional) memory. Since then I have not bagged the
Intronix one bit.

Don't feel bad though. I don't have the where-with-all to put anything
into that market either. But I don't resent those who have.

So you can let the bee out of *your* bonnet now ;-}

Give up trying to read people, you aren't very good at it :->

Dave.

 

[sean4u]

They have some new scopes that do 1GS/s that are replacing the 8xx scopes.
Still _only_ 25K points though.http://www.instek.com/GDS-2000.htm

Hello all. I own a GDS-2000 series scope from Goodwill / Instek. A

GDS-2062. I did a straightforward features/price ratio, and ordered it
immediately. It's well built, feels solid to use. Looks nice. They
haven't finished it yet. You can collect 25K points (total, 25k * 1
channel or 12.5k * 2 channels), but only zoom in (0, 1 or 2 levels, as
far as I can see) on the centre of the sample window - no panning. The
extra detail at either end isn't available. After I calibrate the
scope (well, go through the prescribed motions) the two channels
report 10% different values for the same testpoint (both probes
attached to the same testpoint, at the same time). It locks up from
time to time, requiring switch off - switch on. Switch on takes a
while - I think it's loading the FPGA inside. Sometimes you get a BSOD
that says something reassuring about the FPGA, but it still needs the
power switch to get it to start again. There are little niggly
problems all around with it. I think it has all the hardware it needs
to be a good scope, it just seems like they haven't finished writing
its firmware. I've just given up on a project that should have been
straightforward if the scope worked, but it doesn't. If you can afford
one of these, you should find 8 friends who want one too, and then you
should go and buy one Agilent, and pass it around between you. A
firmware upgrade was mentioned by one of their staff, in the only
reply I got to numerous emails and messages using their web-based
contact forms. If they produce one, I may switch the thing on again.
If they don't, I'm going to give the scope to my 16-month-old
daughter. She'll really, really like it.

Make your own minds up, maybe I'm a bit over emotional about my
purchase.
Regards
Sean

 

[Anthony Fremont]

sean4u wrote:

They have some new scopes that do 1GS/s that are replacing the 8xx
scopes. Still _only_ 25K points
though.http://www.instek.com/GDS-2000.htm

Hello all. I own a GDS-2000 series scope from Goodwill / Instek. A
GDS-2062. I did a straightforward features/price ratio, and ordered it
immediately. It's well built, feels solid to use. Looks nice. They
haven't finished it yet. You can collect 25K points (total, 25k * 1
channel or 12.5k * 2 channels), but only zoom in (0, 1 or 2 levels, as
far as I can see) on the centre of the sample window - no panning. The
extra detail at either end isn't available. After I calibrate the
scope (well, go through the prescribed motions) the two channels
report 10% different values for the same testpoint (both probes
attached to the same testpoint, at the same time). It locks up from
time to time, requiring switch off - switch on. Switch on takes a
while - I think it's loading the FPGA inside. Sometimes you get a BSOD
that says something reassuring about the FPGA, but it still needs the
power switch to get it to start again. There are little niggly
problems all around with it. I think it has all the hardware it needs
to be a good scope, it just seems like they haven't finished writing
its firmware. I've just given up on a project that should have been
straightforward if the scope worked, but it doesn't. If you can afford
one of these, you should find 8 friends who want one too, and then you
should go and buy one Agilent, and pass it around between you. A
firmware upgrade was mentioned by one of their staff, in the only
reply I got to numerous emails and messages using their web-based
contact forms. If they produce one, I may switch the thing on again.
If they don't, I'm going to give the scope to my 16-month-old
daughter. She'll really, really like it.

Make your own minds up, maybe I'm a bit over emotional about my
purchase.

Wow, that really sux and I'm sorry to hear that. :-( That's almost the
exact opposite of my experience with the Rigol I bought. The firmware has
been very stable and seems pretty much finished. I do see a fair amount of
drift the first few minutes while it's warming up, but if you turn the
auto-cal button off and on to force an instant auto-cal, the baseline
centers right back up. Accuracy seems fairly decent and I seem to be able
to view all the data in the capture buffer. It crashed a couple of times
when I was hot swapping a memory stick, but after doing one reload of the
factory settings it hasn't flinched since. I corresponded with the tech
support people in China over a couple of things (pc software key and memory
stick crash) and they were very responsive. And yeah, my two year old
really wants one for herself too. ;-) MOUNTAIN!!! PICTURE!!!!