|
I have the opportunity to grab, likely very affordably, an 11401 and/or a DSA 602A (the latter coming with a couple of 11A34a and one 11A72 plugs), and I've never - yet - considered getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance. But I'd appreciate a bit of education on if/why I'd need one of those at my bench. Where my main scope is an HP 54522A which may soon be replaced with a TDS754D (which I hope to upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.?
|
Bias to the dsa if you can they tend to me MUCH more reliable then the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz. Usual fault in the dsas is you might need to resolder the scams these have known issues around the power pins. Not a huge job but a huge board and some what tedious.
Just my 2 cents worth.
?
On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: I have the opportunity to grab, likely very affordably, an 11401 and/or a DSA 602A (the latter coming with a couple of 11A34a and one 11A72 plugs), and I've never - yet - considered getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance. But I'd appreciate a bit of education on if/why I'd need one of those at my bench. Where my main scope is an HP 54522A which may soon be replaced with a TDS754D (which I hope to upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.?
|
Eric, Thank you for the input. I'll likely get both and keep one. The 11401 "doesn't start," which in my experience is more good news than not. If I can repair it and?let it go to?help with the investment in?both, that would be a great?path forward.?
They seem to be fairly similar units, but what I'm seeing so far is that the?DSA is the higher tier unit of the two (or maybe just age?).?
I'm still humbly looking for some education?on the merits and maybe downsides of digitizing scopes. I've?just not considered them this far.? Radu.?
Bias to the dsa if you can they tend to me MUCH more reliable then the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz. Usual fault in the dsas is you might need to resolder the scams these have known issues around the power pins. Not a huge job but a huge board and some what tedious.
Just my 2 cents worth.
?
On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: I have the opportunity to grab, likely very affordably, an 11401 and/or a DSA 602A (the latter coming with a couple of 11A34a and one 11A72 plugs), and I've never - yet - considered getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance. But I'd appreciate a bit of education on if/why I'd need one of those at my bench. Where my main scope is an HP 54522A which may soon be replaced with a TDS754D (which I hope to upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.?
|
Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and leaving out the 7104 series)
Analog scope pros:
even frequency response up past the scope's bandwidth limit, (think ripple of a sharp cutoff filter)
relatively inexpensive without too terribly many nasty parts (that can vary!).
available in 7000 series with lotsa plugins.
you see everything that happens.? Analog scopes never blink.
Analog scope cons:
unless you have a storage scope, absolutely miserable to capture single shot and low rep-rate events.
storing data from the scope can be tricky, but possible.
not the latest technology (matters to some)
no color displays I know of.
Digital scope pros:
excellent for low rep-rate single shot events within limits
indefinite storage
easy to get data from
additional waveform metrics and measurements
"latest technology"
can have color displays.
Digital scope cons:
Internal processor makes them complicated
internal processor may be difficult to upgrade, both hardware and software
requires a different set of skills to repair.
data not always available to repair.? Many parts obsolete or may have a limited lifetime.
innards of scope remain a mystery to most (if was even available).
may not be modularized (a la 7000 series), so may be less versatile if that's needed.
How's that?
Harvey
storage scopes have a limited storage time and a limited writing rate.
toggle quoted message
Show quoted text
On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote: Eric,
Thank you for the input. I'll likely get both and keep one. The 11401 "doesn't start," which in my experience is more good news than not. If I can repair it and?let it go to?help with the investment in?both, that would be a great?path forward.
They seem to be fairly similar units, but what I'm seeing so far is that the?DSA is the higher tier unit of the two (or maybe just age?).
I'm still humbly looking for some education?on the merits and maybe downsides of digitizing scopes. I've?just not considered them this far.
Radu.
On Tue, Jun 4, 2024 at 4:45?PM Eric via groups.io <> <ericsp@...> wrote:
Bias to the dsa if you can they tend to me MUCH more reliable then
the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
Usual fault in the dsas is you might need to resolder the scams
these have known issues around the power pins. Not a huge job but
a huge board and some what tedious.
Just my 2 cents worth.
On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via groups.io
<> <vondicher@...> wrote:
I have the opportunity to grab, likely very affordably, an
11401 and/or a DSA 602A (the latter coming with a couple of
11A34a and one 11A72 plugs), and I've never - yet - considered
getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance.
But I'd appreciate a bit of education on if/why I'd need one
of those at my bench. Where my main scope is an HP 54522A
which may soon be replaced with a TDS754D (which I hope to
upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.
|
Harvey and all, I probably did a poor job at explaining what I'm looking for. Which is specifically the differences (pros and cons) between different types of digital scopes - namely between "digitizing" (which I take to be the same as "sampling," but that's not quite accurate?) and the other digital types. So within the overall "digital" category of scopes. Mostly looking for practical impressions, hands-on experience with all these types and how they're different.?
The best I could find is this guideline by Tektronix themselves:?. But still, I'm looking for practical thoughts, coming from actual use in actual?applications.?
One particular characteristic of the sampling scopes seems to be their capacity to work with "much higher frequency components" in incoming signals than the other types. I assume that's why they're capable of viewing, for instance, rising edges in the ps. And yet, those two I'm looking at are limited, I think, to 500MHz (11401) and 1GHz (DSA 602A). Nothing to write home about. It doesn't sound like they're capable of seeing much faster signals than your regular DSO.?
I've used a conventional digital scope for years (the HP 54522A I mentioned). I've also used, rather occasionally in the past few years, either my 7104 or my 7704 analog scopes. This is because it allows me to see things I'd not see otherwise. For instance, they're irreplaceable in work such as aligning FM tuners. I also have a TDS 754D, which, if I manage to fix all faults (halfway there), will probably replace the 54522A as my main scope. So at my bench I currently cover the DSO, DPO, and analog types.?
I have the opportunity to get (and play with, so I'd learn how they're different from my other scopes) those two "digitizing" scopes I mentioned. Again, I assume they are the same as what Tek calls "sampling" in the above article, and fundamentally different from the 54522A or the 754D I have at my bench already. Do I need a "sampling" scope?...
Thank you, Radu.?
Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and
leaving out the 7104 series)
Analog scope pros:
even frequency response up past the scope's bandwidth limit, (think
ripple of a sharp cutoff filter)
relatively inexpensive without too terribly many nasty parts (that can
vary!).
available in 7000 series with lotsa plugins.
you see everything that happens.? Analog scopes never blink.
Analog scope cons:
unless you have a storage scope, absolutely miserable to capture single
shot and low rep-rate events.
storing data from the scope can be tricky, but possible.
not the latest technology (matters to some)
no color displays I know of.
Digital scope pros:
excellent for low rep-rate single shot events within limits
indefinite storage
easy to get data from
additional waveform metrics and measurements
"latest technology"
can have color displays.
Digital scope cons:
Internal processor makes them complicated
internal processor may be difficult to upgrade, both hardware and software
requires a different set of skills to repair.
data not always available to repair.? Many parts obsolete or may have a
limited lifetime.
innards of scope remain a mystery to most (if was even available).
may not be modularized (a la 7000 series), so may be less versatile if
that's needed.
How's that?
Harvey
storage scopes have a limited storage time and a limited writing rate.
On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote:
> Eric,
> Thank you for the input. I'll likely get both and keep one. The 11401
> "doesn't start," which in my experience is more good news than not. If
> I can repair it and?let it go to?help with the investment in?both,
> that would be a great?path forward.
>
> They seem to be fairly similar units, but what I'm seeing so far is
> that the?DSA is the higher tier unit of the two (or maybe just age?).
>
> I'm still humbly looking for some education?on the merits and maybe
> downsides of digitizing scopes. I've?just not considered them this far.
> Radu.
>
> On Tue, Jun 4, 2024 at 4:45?PM Eric via <>
> <ericsp=[email protected]> wrote:
>
>? ? ?Bias to the dsa if you can they tend to me MUCH more reliable then
>? ? ?the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
>? ? ?Usual fault in the dsas is you might need to resolder the scams
>? ? ?these have known issues around the power pins. Not a huge job but
>? ? ?a huge board and some what tedious.
>
>
>? ? ?Just my 2 cents worth.
>
>
>? ? ?On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via
>? ? ?<> <vondicher=[email protected]> wrote:
>
>? ? ? ? ?I have the opportunity to grab, likely very affordably, an
>? ? ? ? ?11401 and/or a DSA 602A (the latter coming with a couple of
>? ? ? ? ?11A34a and one 11A72 plugs), and I've never - yet - considered
>? ? ? ? ?getting a digitizing scopes, which I'm not very familiar with.
>
>? ? ? ? ?One feature I am aware of is outstanding risetime performance.
>? ? ? ? ?But I'd appreciate a bit of education on if/why I'd need one
>? ? ? ? ?of those at my bench. Where my main scope is an HP 54522A
>? ? ? ? ?which may soon be replaced with a TDS754D (which I hope to
>? ? ? ? ?upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
>
>? ? ? ? ?Thank you!
>? ? ? ? ?Radu.
>
>
|
Sampling scopes have a high speed front end (the sampler) and a low speed storage component. The display is built up over a large number of samples over time.
This requires a trigger that is stable and is usually derived separately from the signal being measured.
I have a CSA803 with a number of input modules and at this time only use it for the TDR function to measure impedance of circuit boards and cables/adapters where needed.
A regular high speed (500MHz input or higher) digital scope is much more useful for daily operation.
ed
|
That's a good summary. One aspect of DSOs that you didn't mention is aliasing.
DaveD
KC0WJN
==============================
All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994)
==============================
toggle quoted message
Show quoted text
On Jun 4, 2024, at 22:58, Harvey White via groups.io <madyn@...> wrote:
?Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and leaving out the 7104 series)
Analog scope pros:
even frequency response up past the scope's bandwidth limit, (think ripple of a sharp cutoff filter)
relatively inexpensive without too terribly many nasty parts (that can vary!).
available in 7000 series with lotsa plugins.
you see everything that happens. Analog scopes never blink.
Analog scope cons:
unless you have a storage scope, absolutely miserable to capture single shot and low rep-rate events.
storing data from the scope can be tricky, but possible.
not the latest technology (matters to some)
no color displays I know of.
Digital scope pros:
excellent for low rep-rate single shot events within limits
indefinite storage
easy to get data from
additional waveform metrics and measurements
"latest technology"
can have color displays.
Digital scope cons:
Internal processor makes them complicated
internal processor may be difficult to upgrade, both hardware and software
requires a different set of skills to repair.
data not always available to repair. Many parts obsolete or may have a limited lifetime.
innards of scope remain a mystery to most (if was even available).
may not be modularized (a la 7000 series), so may be less versatile if that's needed.
How's that?
Harvey
storage scopes have a limited storage time and a limited writing rate.
On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote:
Eric,
Thank you for the input. I'll likely get both and keep one. The 11401 "doesn't start," which in my experience is more good news than not. If I can repair it and let it go to help with the investment in both, that would be a great path forward.
They seem to be fairly similar units, but what I'm seeing so far is that the DSA is the higher tier unit of the two (or maybe just age?).
I'm still humbly looking for some education on the merits and maybe downsides of digitizing scopes. I've just not considered them this far.
Radu.
On Tue, Jun 4, 2024 at 4:45?PM Eric via groups.io <> <ericsp@...> wrote:
Bias to the dsa if you can they tend to me MUCH more reliable then
the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
Usual fault in the dsas is you might need to resolder the scams
these have known issues around the power pins. Not a huge job but
a huge board and some what tedious.
Just my 2 cents worth.
On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via groups.io
<> <vondicher@...> wrote:
I have the opportunity to grab, likely very affordably, an
11401 and/or a DSA 602A (the latter coming with a couple of
11A34a and one 11A72 plugs), and I've never - yet - considered
getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance.
But I'd appreciate a bit of education on if/why I'd need one
of those at my bench. Where my main scope is an HP 54522A
which may soon be replaced with a TDS754D (which I hope to
upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.
|
Two things come to mind. The extremely fast & the extremely slow signals. The time base on the DSA is quicker then then time base on the 7104 so especially for edge work the 7104 gets down to 200ps/div the DSA gets down to 50ps/div so quite a bit more zoom. This is sweeping way faster than the phosphor in a 7104 can react for brightness even with the MCP. Analog seems to top out at 1Ghz I am not aware of anything faster.
We have 110 Ghz of bandwidth in digital. Though that scope is a cool 1.5 Million US.
Zen
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Dave Daniel via groups.io Sent: Wednesday, June 5, 2024 7:59 AM To: [email protected]Subject: Re: [TekScopes2] Digitizing scopes vs. DSOs, DPOs, etc.?... That's a good summary. One aspect of DSOs that you didn't mention is aliasing. DaveD KC0WJN ============================== All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994) ============================== On Jun 4, 2024, at 22:58, Harvey White via groups.io <madyn@...> wrote:
?Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and
leaving out the 7104 series)
Analog scope pros:
even frequency response up past the scope's bandwidth limit, (think
ripple of a sharp cutoff filter)
relatively inexpensive without too terribly many nasty parts (that can vary!).
available in 7000 series with lotsa plugins.
you see everything that happens. Analog scopes never blink.
Analog scope cons:
unless you have a storage scope, absolutely miserable to capture single shot and low rep-rate events.
storing data from the scope can be tricky, but possible.
not the latest technology (matters to some)
no color displays I know of.
Digital scope pros:
excellent for low rep-rate single shot events within limits
indefinite storage
easy to get data from
additional waveform metrics and measurements
"latest technology"
can have color displays.
Digital scope cons:
Internal processor makes them complicated
internal processor may be difficult to upgrade, both hardware and
software
requires a different set of skills to repair.
data not always available to repair. Many parts obsolete or may have a limited lifetime.
innards of scope remain a mystery to most (if was even available).
may not be modularized (a la 7000 series), so may be less versatile if that's needed.
How's that?
Harvey
storage scopes have a limited storage time and a limited writing rate.
On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote:
Eric,
Thank you for the input. I'll likely get both and keep one. The 11401 "doesn't start," which in my experience is more good news than not. If I can repair it and let it go to help with the investment in both, that would be a great path forward.
They seem to be fairly similar units, but what I'm seeing so far is that the DSA is the higher tier unit of the two (or maybe just age?).
I'm still humbly looking for some education on the merits and maybe downsides of digitizing scopes. I've just not considered them this far.
Radu.
On Tue, Jun 4, 2024 at 4:45?PM Eric via groups.io <> <ericsp@...> wrote:
Bias to the dsa if you can they tend to me MUCH more reliable then
the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
Usual fault in the dsas is you might need to resolder the scams
these have known issues around the power pins. Not a huge job but
a huge board and some what tedious.
Just my 2 cents worth.
On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via groups.io
<> <vondicher@...> wrote:
I have the opportunity to grab, likely very affordably, an
11401 and/or a DSA 602A (the latter coming with a couple of
11A34a and one 11A72 plugs), and I've never - yet - considered
getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance.
But I'd appreciate a bit of education on if/why I'd need one
of those at my bench. Where my main scope is an HP 54522A
which may soon be replaced with a TDS754D (which I hope to
upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
Thank you!
Radu.
|
From what I remember, the DSA602 had a large selection of waveform math functions.
Hugh Gilbert
On Wed, Jun 5, 2024 at 9:18?AM Zentronics42 via <Zentronics42= [email protected]> wrote: Two things come to mind. The extremely fast & the extremely slow signals. The time base on the DSA is quicker then then time base on the 7104 so especially for edge work? the 7104 gets down to 200ps/div the DSA gets down to 50ps/div so quite a bit more zoom. This is sweeping way faster than the phosphor in a 7104 can react for brightness even with the MCP. Analog seems to top out at 1Ghz I am not aware of anything faster.
We have 110 Ghz of bandwidth in digital. Though that scope is a cool 1.5 Million US.
Zen
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Dave Daniel via
Sent: Wednesday, June 5, 2024 7:59 AM
To: [email protected]
Subject: Re: [TekScopes2] Digitizing scopes vs. DSOs, DPOs, etc.?...
That's a good summary. One aspect of DSOs that you didn't mention is aliasing.
DaveD
KC0WJN
==============================
All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994) ==============================
> On Jun 4, 2024, at 22:58, Harvey White via <madyn=[email protected]> wrote:
>
> ?Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and
> leaving out the 7104 series)
>
> Analog scope pros:
>
> even frequency response up past the scope's bandwidth limit, (think
> ripple of a sharp cutoff filter)
>
> relatively inexpensive without too terribly many nasty parts (that can vary!).
>
> available in 7000 series with lotsa plugins.
>
> you see everything that happens.? Analog scopes never blink.
>
> Analog scope cons:
>
> unless you have a storage scope, absolutely miserable to capture single shot and low rep-rate events.
>
> storing data from the scope can be tricky, but possible.
>
> not the latest technology (matters to some)
>
> no color displays I know of.
>
> Digital scope pros:
>
> excellent for low rep-rate single shot events within limits
>
> indefinite storage
>
> easy to get data from
>
> additional waveform metrics and measurements
>
> "latest technology"
>
> can have color displays.
>
> Digital scope cons:
>
> Internal processor makes them complicated
>
> internal processor may be difficult to upgrade, both hardware and
> software
>
> requires a different set of skills to repair.
>
> data not always available to repair.? Many parts obsolete or may have a limited lifetime.
>
> innards of scope remain a mystery to most (if was even available).
>
> may not be modularized (a la 7000 series), so may be less versatile if that's needed.
>
> How's that?
>
> Harvey
>
>
> storage scopes have a limited storage time and a limited writing rate.
>
>> On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote:
>> Eric,
>> Thank you for the input. I'll likely get both and keep one. The 11401 "doesn't start," which in my experience is more good news than not. If I can repair it and let it go to help with the investment in both, that would be a great path forward.
>>
>> They seem to be fairly similar units, but what I'm seeing so far is that the DSA is the higher tier unit of the two (or maybe just age?).
>>
>> I'm still humbly looking for some education on the merits and maybe downsides of digitizing scopes. I've just not considered them this far.
>> Radu.
>>
>> On Tue, Jun 4, 2024 at 4:45?PM Eric via <> <ericsp=[email protected]> wrote:
>>
>>? ? Bias to the dsa if you can they tend to me MUCH more reliable then
>>? ? the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
>>? ? Usual fault in the dsas is you might need to resolder the scams
>>? ? these have known issues around the power pins. Not a huge job but
>>? ? a huge board and some what tedious.
>>
>>
>>? ? Just my 2 cents worth.
>>
>>
>>? ? On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via
>>? ? <> <vondicher=[email protected]> wrote:
>>
>>? ? ? ? I have the opportunity to grab, likely very affordably, an
>>? ? ? ? 11401 and/or a DSA 602A (the latter coming with a couple of
>>? ? ? ? 11A34a and one 11A72 plugs), and I've never - yet - considered
>>? ? ? ? getting a digitizing scopes, which I'm not very familiar with.
>>
>>? ? ? ? One feature I am aware of is outstanding risetime performance.
>>? ? ? ? But I'd appreciate a bit of education on if/why I'd need one
>>? ? ? ? of those at my bench. Where my main scope is an HP 54522A
>>? ? ? ? which may soon be replaced with a TDS754D (which I hope to
>>? ? ? ? upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
>>
>>? ? ? ? Thank you!
>>? ? ? ? Radu.
>
>
>
>
>
>
|
Ah, perhaps a bit less help here, but I can make a few comments.
I have a 7S11 and a 7T11 along with a sampling head (S6) and the probe that comes with another sampling head.? This effectively extends the frequency response to about 3 Ghz (I think) or 1 Ghz with the probe.? The idea is that these could be used in a relatively low bandwidth scope to give some higher frequency response.
These effectively work like part of a digital scope.? I don't remember how the 7S11 works, but it stores the built up samples and then reads them out at a much lower rate that the host scope can tolerate.? IIRC, these plugins do poorly on single shot events, so there's a difference.
The sampling heads, like any other such device, are low voltage, 50 ohm and fragile.
So do you need these?
Much depends on the frequency (and amplitude) of the signal you're trying to see.? For low enough signal frequencies, a good analog or digital scope will work.
For 7000 series scopes, you can use the 7S11/7T11 (or 7s##) plugins depending on the desired frequency.? Some people dislike the 7S/7T combination, which can be tricky to set up and use.
These came along at a time where the scope frequencies were limited (say, 7904) and the 7104 was either absent or too expensive .
Unless you're working with 1 GHz plus, and some do, you may not need the bandwidth.
I have this, it generally stays on the shelf.? I got this because it was available on pretty much a one time deal.
Harvey
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Show quoted text
On 6/5/2024 6:33 AM, Radu Bogdan Dicher wrote: Harvey and all,
I probably did a poor job at explaining what I'm looking for. Which is specifically the differences (pros and cons) between different types of /digital/ scopes - namely between "digitizing" (which I take to be the same as "sampling," but that's not quite accurate?) and the other digital types. So within the overall "digital" category of scopes. Mostly looking for practical impressions, hands-on experience with all these types and how they're different.
The best I could find is this guideline by Tektronix themselves: . But still, I'm looking for practical thoughts, coming from actual use in actual?applications.
One particular characteristic of the sampling scopes seems to be their capacity to work with "much higher frequency components" in incoming signals than the other types. I assume that's why they're capable of viewing, for instance, rising edges in the ps. And yet, those two I'm looking at are limited, I think, to 500MHz (11401) and 1GHz (DSA 602A). Nothing to write home about. It doesn't sound like they're capable of seeing much faster signals than your regular DSO.
I've used a conventional digital scope for years (the HP 54522A I mentioned). I've also used, rather occasionally in the past few years, either my 7104 or my 7704 analog scopes. This is because it allows me to see things I'd not see otherwise. For instance, they're irreplaceable in work such as aligning FM tuners. I also have a TDS 754D, which, if I manage to fix all faults (halfway there), will probably replace the 54522A as my main scope. So at my bench I currently cover the DSO, DPO, and analog types.
I have the opportunity to get (and play with, so I'd learn how they're different from my other scopes) those two "digitizing" scopes I mentioned. Again, I assume they are the same as what Tek calls "sampling" in the above article, and fundamentally different from the 54522A or the 754D I have at my bench already. Do I need a "sampling" scope?...
Thank you,
Radu.
On Tue, Jun 4, 2024 at 7:58?PM Harvey White via groups.io <> <madyn@...> wrote:
Perhaps I can help a little, comparing, say a 7904 and a TDS540 (and
leaving out the 7104 series)
Analog scope pros:
even frequency response up past the scope's bandwidth limit, (think
ripple of a sharp cutoff filter)
relatively inexpensive without too terribly many nasty parts (that
can
vary!).
available in 7000 series with lotsa plugins.
you see everything that happens.? Analog scopes never blink.
Analog scope cons:
unless you have a storage scope, absolutely miserable to capture
single
shot and low rep-rate events.
storing data from the scope can be tricky, but possible.
not the latest technology (matters to some)
no color displays I know of.
Digital scope pros:
excellent for low rep-rate single shot events within limits
indefinite storage
easy to get data from
additional waveform metrics and measurements
"latest technology"
can have color displays.
Digital scope cons:
Internal processor makes them complicated
internal processor may be difficult to upgrade, both hardware and
software
requires a different set of skills to repair.
data not always available to repair.? Many parts obsolete or may
have a
limited lifetime.
innards of scope remain a mystery to most (if was even available).
may not be modularized (a la 7000 series), so may be less
versatile if
that's needed.
How's that?
Harvey
storage scopes have a limited storage time and a limited writing rate.
On 6/4/2024 9:16 PM, Radu Bogdan Dicher wrote:
> Eric,
> Thank you for the input. I'll likely get both and keep one. The
11401
> "doesn't start," which in my experience is more good news than
not. If
> I can repair it and?let it go to?help with the investment in?both,
> that would be a great?path forward.
>
> They seem to be fairly similar units, but what I'm seeing so far is
> that the?DSA is the higher tier unit of the two (or maybe just
age?).
>
> I'm still humbly looking for some education?on the merits and maybe
> downsides of digitizing scopes. I've?just not considered them
this far.
> Radu.
>
> On Tue, Jun 4, 2024 at 4:45?PM Eric via groups.io
<> <>
> <ericsp@...> wrote:
>
>? ? ?Bias to the dsa if you can they tend to me MUCH more
reliable then
>? ? ?the 11,000 series. The 602 is 1 ghz up to 12 channels of 300mhz.
>? ? ?Usual fault in the dsas is you might need to resolder the scams
>? ? ?these have known issues around the power pins. Not a huge
job but
>? ? ?a huge board and some what tedious.
>
>
>? ? ?Just my 2 cents worth.
>
>
>? ? ?On Tue, Jun 4, 2024, 9:55 AM Radu Bogdan Dicher via
groups.io <>
>? ? ?<> <vondicher@...> wrote:
>
>? ? ? ? ?I have the opportunity to grab, likely very affordably, an
>? ? ? ? ?11401 and/or a DSA 602A (the latter coming with a couple of
>? ? ? ? ?11A34a and one 11A72 plugs), and I've never - yet -
considered
>? ? ? ? ?getting a digitizing scopes, which I'm not very familiar
with.
>
>? ? ? ? ?One feature I am aware of is outstanding risetime
performance.
>? ? ? ? ?But I'd appreciate a bit of education on if/why I'd need one
>? ? ? ? ?of those at my bench. Where my main scope is an HP 54522A
>? ? ? ? ?which may soon be replaced with a TDS754D (which I hope to
>? ? ? ? ?upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
>
>? ? ? ? ?Thank you!
>? ? ? ? ?Radu.
>
>
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On Tue, Jun 4, 2024 at 06:55 AM, Radu Bogdan Dicher wrote:
DSA 602A
At over 80 pounds... I can't pick the thing up, to move it. 11401 is about half the weight, at about 40 pounds.
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On Wed, Jun 5, 2024 at 04:39 AM, Ed (scskits) wrote:
The display is built up over a large number of samples over time.
That's commonly called (at least common to me)... equivalent time sampling. Both DSO, and DSO, can do that... but DSO is not the same thing as DSO. One is a digital sampling oscilloscope, and the other is a digital storage oscilloscope. To my mind, the most important difference, between the two, resides in the 'front end' In a digital storage oscilloscope, the 'switch' is behind the front end. In a digital sampling oscilloscope the 'switch' proceeds the front end... if that makes sense. The idea is that in a digital sampling oscilloscope, the 'signal' to be characterized, will not be 'processed' by the front end, before it is sampled. That's a great advantage for trying to characterize high frequency components of a signal that would be diminished by the front end of a regular digital storage oscilloscope. The disadvantage of the digital storage oscilloscope is the switch (or the sampling diodes) don't have the same dynamic range as the front end of a digital storage oscilloscope. And the switch can't be protected. (That would alter the signal being characterized.) We are looking at a few volts or less. Judging from the number of input switches, and sampling heads, that have been launched into outer space, and appear on Ebay, at huge prices... that limitation isn't well understood, or respected. Costly and expensive... universities, and the usual military industrial researchers, got them because they needed them, and we got them years later, not because we need them... but, because we can. For example... fast pulse radar needs well characterized pulses.. and the analog scopes, or digital storage oscilloscopes (such as they were at the time) couldn't do that. Digital sampling oscilloscope was expensive... but, it could do that. Not sure how many guys are doing that in the home basement, these days... but the older digital sampling oscilloscopes are good for holding the basement floor down... if you need that.
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Reading with great deal of interest all the great input!
Roy - thank you for pointing out to me the weight aspect, which is extremely important. I didn't know what sort of behemoth the 602A is...
Radu.?
On Wed, Jun 5, 2024 at 04:39 AM, Ed (scskits) wrote:
The display is built up over a large number of samples over time.
That's commonly called (at least common to me)... equivalent time sampling.
Both DSO, and DSO, can do that... but DSO is not the same thing as DSO.
One is a digital sampling oscilloscope, and the other is a digital storage oscilloscope.
To my mind, the most important difference, between the two, resides in the 'front end'
In a digital storage oscilloscope, the 'switch' is behind the front end.
In a digital sampling oscilloscope the 'switch' proceeds the front end... if that makes sense.
The idea is that in a digital sampling oscilloscope, the 'signal' to be characterized, will not be 'processed' by the front end, before it is sampled.
That's a great advantage for trying to characterize high frequency components of a signal that would be diminished by the front end of a regular digital storage oscilloscope.
The disadvantage of the digital storage oscilloscope is the switch (or the sampling diodes) don't have the same dynamic range as the front end of a digital storage oscilloscope. And the switch can't be protected. (That would alter the signal being characterized.)
We are looking at a few volts or less.
Judging from the number of input switches, and sampling heads, that have been launched into outer space, and appear on Ebay, at huge prices... that limitation isn't well understood, or respected.
Costly and expensive... universities, and the usual military industrial researchers, got them because they needed them, and we got them years later, not because we need them... but, because we can.
For example... fast pulse radar needs well characterized pulses.. and the analog scopes, or digital storage oscilloscopes (such as they were at the time) couldn't do that. Digital sampling oscilloscope was expensive... but, it could do that.
Not sure how many guys are doing that in the home basement, these days... but the older digital sampling oscilloscopes are good for holding the basement floor down... if you need that.
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On Wed, Jun 5, 2024 at 04:39 AM, Ed (scskits) wrote:
The display is built up over a large number of samples over time.
That's commonly called (at least common to me)... equivalent time sampling.
Both DSO, and DSO, can do that... but DSO is not the same thing as DSO.
One is a digital sampling oscilloscope, and the other is a digital storage oscilloscope.
To my mind, the most important difference, between the two, resides in the 'front end'
In a digital storage oscilloscope, the 'switch' is behind the front end.
In a digital sampling oscilloscope the 'switch' proceeds the front end... if that makes sense.
The idea is that in a digital sampling oscilloscope, the 'signal' to be characterized, will not be 'processed' by the front end, before it is sampled.
That's a great advantage for trying to characterize high frequency components of a signal that would be diminished by the front end of a regular digital storage oscilloscope.
The disadvantage of the digital storage oscilloscope is the switch (or the sampling diodes) don't have the same dynamic range as the front end of a digital storage oscilloscope. And the switch can't be protected. (That would alter the signal being characterized.)
We are looking at a few volts or less.
Judging from the number of input switches, and sampling heads, that have been launched into outer space, and appear on Ebay, at huge prices... that limitation isn't well understood, or respected.
Costly and expensive... universities, and the usual military industrial researchers, got them because they needed them, and we got them years later, not because we need them... but, because we can.
For example... fast pulse radar needs well characterized pulses.. and the analog scopes, or digital storage oscilloscopes (such as they were at the time) couldn't do that. Digital sampling oscilloscope was expensive... but, it could do that.
Not sure how many guys are doing that in the home basement, these days... but the older digital sampling oscilloscopes are good for holding the basement floor down... if you need that.
That is a useful summary of terminology and concepts. They continue to be misunderstood/misapplied, all too often.
To illustrate some of the points with concrete examples of an analogue sampling scopes, neither digital nor storage.
A well-known example is the Tek 1502 TDR (not 1502A nor 1502B nor 1503, which are completely different). The "starry" twinkling display is beautiful and hypnotic; I've completely failed to capture it on video.
A lesser-known example is a strange and wonderful beast, but definitely not a general purpose scope. I have a 1970 Philips PM3400 scope. That has a 200ps risetime (->1.7GHz), yet the transistors in the signal path are common-or-garden BC107/BC177 with an fT of 200MHz. (There are a couple of 2GHz transistors, in the trigger circuit) Obviously there are no ADCs, let alone digital circuits and microprocessors! As for price: ?25, at a radio rally :)
The inputs are sampled with diodes, maximum input +-1.6V. Since the input signal is ignored except at the sampling instant, there is no recovery time when the front end is overloaded. That means is it possible to observe the last 0.01% of the risetime, even with a 3V step and a 1mV/div vertical sensitivity. That's "tricky" to do with conventional scopes.
I ought to write it up sometime, somewhere.
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Dave:
Yes, I totally forgot about the aliasing.
I remember many college grads over the years using a digital scope for the first time and looking at a waveform at the wrong sample rate.
ed
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On Wed, Jun 5, 2024 at 09:00 PM, Roy Thistle wrote:
Both DSO, and DSO, can do that... but DSO is not the same thing as DSO.
One is a digital sampling oscilloscope, and the other is a digital storage oscilloscope.
To my mind, the most important difference, between the two, resides in the 'front end'
In a digital storage oscilloscope, the 'switch' is behind the front end.
In a digital sampling oscilloscope the 'switch' proceeds the front end... if that makes sense.
The idea is that in a digital sampling oscilloscope, the 'signal' to be characterized, will not be 'processed' by the front end, before it is sampled.
I think "Digital Sampling Oscilloscope" is a misnomer or at least a pleonasm: *All* digital oscilloscopes do their thing by sampling, most doing some analog processing before digitizing. There is no such thing as a "Digital Non-sampling Oscilloscope". Traditional analog oscilloscopes don't use sampling. All digital 'scopes work by taking samples of the input signal and storing the result after processing. Traditionally, there are two main ways of doing that: - "Real Time Sampling" (RTS): Samples of the input signal are taken in quick succession, quick enough to allow putting them in sequence, doing some processing, then storing and displaying them. The sampling speed must be at least around 5 samples per period of the highest frequency component in the signal to allow storing and displaying a representative picture of a single event/waveform. With continuous waveforms, this process just repeats. - "Equivalent Time Sampling" (ETS): Samples are taken at a rate much below the input frequency over many periods of the input signal, at a different (phase) point each period. After a number of periods, enough samples have been taken to allow reconstructing the input signal, because each data point is stored in amplitude *and* (slightly) different time each period, relative to some (any) reference point. Since many periods are needed to assemble the stored waveform, single/shot storage is not possible; storing continuous waveforms is what ETS does. The frequency ratio between sampling rate, input signal frequency and display frequency may cause aliasing, result in artefacts. Aliasing used to be a problem with early digital 'scopes.? RTS used to be the only acquisition method for digital storage oscilloscopes (DSO's). ETS was developed and added later. All analog sampling 'scopes work in an ETS-like mode: Amplitude samples are taken and stored (in an analog way), together with time information. Acquisition of the samples may be done randomly in time and is used on purpose in some cases. Aliasing is a phenomenon in analog sampling 'scopes, like in early/simple digital 'scopes. Hybrids were developed over time, allowing digital sampling in an analog 'scope, mostly ETS only. The Tek 7854 is an example allowing both, albeit with a very slow sampling rate (ISTR 70 kHz), the Tek 2252 portable used digital storage (ETS) of the analog input signal to print - and only print - a waveform on paper. The Tek 468 portable, although being a 100 MHz analog 'scope, provided a storage mechanism at (ISTR) 20 MHz, severely limiting usable bandwidth in storage mode. All analog sampling 'scopes (AFAIK), took their samples by sampling the input signal directly, even Tek's 7S14 (5S14). By circumventing analog amplification and attenuation of the input signal before sampling, large BW was realized. I can't remember reading in this thread that a significant advantage of this arrangement is the possibility of a better representation of the input signal in the output, even for input signals that could be handled by purely analog circuits. Tek's 7S14 is an example. Raymond
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On Tue, Jun 4, 2024 at 6:55?AM Radu Bogdan Dicher via groups.io <vondicher@...> wrote:
I have the opportunity to grab, likely very affordably, an 11401 and/or a DSA 602A (the latter coming with a couple of 11A34a and one 11A72 plugs), and I've never - yet - considered getting a digitizing scopes, which I'm not very familiar with.
One feature I am aware of is outstanding risetime performance. But I'd appreciate a bit of education on if/why I'd need one of those at my bench. Where my main scope is an HP 54522A which may soon be replaced with a TDS754D (which I hope to upgrade to 784D), a 7104 analog, a 7704A, 453A, etc.
These scopes are all wildly different in construction. The 11401 is a 500MHz equivalent time sampling 10bit scope with a (nowadays..) very slow sample rate of 20Msps that bothers a lot of people but is still useful. As a member of the 11k series I think it is a worthwhile scope to keep on hand if you have other 11k plugins but not worth going out of your way to get one especially on its own. The 10 bit ADC makes it a nice complement to a DSA and you can share some plugins. The DSA is an entirely separate beast, it has a 2 Gsps samplerate and is therefore a realtime 1ghz scope. The DSA could be used similarly to your TDS754/784, 54522A, and vice versa. Many hobby and a non-trivial number of professions could easily get around with a DSA even in this year as a primary scope if you have the room for one. Since you have two nice digital scopes already, you are not adding much to your capabilities with the 11k or DSA but they are a delight to use and they can both do some interesting tricks like 12 channels or differential channels. Thank you!
Radu.
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On 5/6/24 20:33, Radu Bogdan Dicher wrote: Harvey and all,
I probably did a poor job at explaining what I'm looking for. Which is specifically the differences (pros and cons) between different types of /digital/ scopes - namely between "digitizing" (which I take to be the same as "sampling," but that's not quite accurate?) and the other digital types. So within the overall "digital" category of scopes. Mostly looking for practical impressions, hands-on experience with all these types and how they're different. ... The best DSOs are the ones that run their maximum sampling rate at all sweep speeds. Eg, 1Gs/s when sweeping at 1sec/dev. The screen pixels are the result of high speed multiply/accumulate or box car averaging at high speeds on custom ASICs. That way, there's no chance of aliasing effects below half the sampling frequency. The cheapy DSOs use FPGAs that are no where fast enough, and so reduce their sampling rate at the lower sweep speeds.
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On Thu, Jun 6, 2024 at 02:09 PM, Raymond Domp Frank wrote:
I think "Digital Sampling Oscilloscope" is a misnomer or at least a pleonasm.
IMO, it's the acronymization, which produces an acronym ambiguity... which isn't sufficiently disambiguated by the context... at least by some. For example: Digital Storage Oscilloscope Digital Sampling Oscilloscope Digitizing Storage Oscilloscope DSO may be ambiguous; but, 'Digital Storage Oscilloscope" and "Digital Sampling Oscilloscope" ... within the context of the enormous bucks they cost (especially in the last century) would be well understood by the engineers responsible for acquiring them... unless they wanted another job. Thus while one can say.... generally... a Digital Sampling Oscilloscope uses... especially today... digital memory storage... to store the sampled signal...and so is a kind of "Digital Storage Oscilloscope" ...the term "Digital Sampling Oscilloscope" is useful for drawing a distinction between the two.
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On Wed, Jun 5, 2024 at 03:33 AM, Radu Bogdan Dicher wrote:
1GHz (DSA 602A). Nothing to write home about. It doesn't sound like they're capable of seeing much faster signals than your regular DSO
Tektronix 11800 or CSA800... for examples... use 'sampling heads' like the the 7S11 sampling plugin (with an S-X sampling head), for 7000 series frames.? Those are what I would call 'sampling oscilloscopes' even though they might be mostly analog, or mostly digital... they use a sampling head, to 'sample' the signal to be analyzed (observed) 602A isn't that... unless there is a plugin for it that has a sampling head slot (for a sampling head plugin)... or there is a plugin amp for it that uses a 'sampling head' internally. (before the attenuator in the signal path.) 602A frame came? with 11A72 dual channel amp, which are just amplifiers, with some 'special digital sauce, to tell if one has been a bad boy using them, or to tell the mainframe 'brain' what to do.)? The 'sampling' happens in the frame, behind the 11A72? BNC ports, attenuators, amplifiers, and delay lines... on and in... the 11A72. It's same similar for 11401. So ya... "Nothing to write home about..." in light of modern wide band, high sample rate, even Chinese, oscilloscopes. Besides people asking way too much for them... the beauty of a 602A... in particular is the thing comes with a free hernia. (Trust me.)
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