Keysight DSOX4024A vs Tektronix MDO4024C

[knights]

Hello EEVBlog,

I'm looking to get an electronics bench set up for my company (we are working on embedded systems design - primarily at the PCB level in a wide-range of application areas). At the moment, we are not doing anything in the high-frequency realm and need the equipment for signal integrity testing of communication protocols (SPI, UART, I2C, USB2.0) as well as verification of power regulation/delivery circuits for solar charging systems.

I reached out to a few distributors/manufacturers (Keysight, Tek, and LeCroy) and will be making a decision on some equipment shortly. I would like to get your thoughts/opinions on the Keysight DSOX4024A vs the Tektronix MDO4024C. I have been quoted the same price for these two scopes including the full application bundles - approx. CAD $6500. Surprising because the Tek scope's MSRP is significantly higher.

The one glaring thing that stands out is that the Tek scope has significantly higher memory (20M vs. 4M for the Keysight scope). How much of an impact will this make, especially with Keysight touting its 'segmented memory' feature? The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/

Are there any glaring deficiencies between these scopes or crucial features that would make you choose one over the other (assuming they are the same price)?

Thanks!

[nctnico]

Did you look at this thread?
https://www.eevblog.com/forum/testgear/is-there-a-good-midrange-($3k-to-$10k)-scope/

[knights]

Did you look at this thread?
https://www.eevblog.com/forum/testgear/is-there-a-good-midrange-($3k-to-$10k)-scope/

I did, indeed! I was hoping for some specific comparisons between these two scopes which wasn't discussed in that thread. Since it is the first purchase for our company, I guess I was looking for some feedback to make me feel reassured.

[nctnico]

Judging from experience from others I wouldn't want the Tektronix MDO3000/MDO4000 series scope. The UI and decoding would be too slow otherwise it the Tektronix definitely has the better specs so in a way both the DSOX4024A and Tektronix MDO4024C wouldn't be the most ideal choice. If I had to choose between the two I'd go for the Keysight DSOX4024A but when looking at the whole spectrum of available scopes I'd buy something completely different.

[knights]

Judging from experience from others I wouldn't want the Tektronix MDO3000/MDO4000 series scope. The UI and decoding would be too slow.

May I ask which scope(s) you use and your experience with them?

[sambran]

Spec wise I think the most obvious difference is that Tek has the SA and Keysight has a much faster sample rate.

Specs aside I think the UI is very important and this is probably a matter of taste (I personally prefer Keysight). I would highly recommend asking your distributor to let you evaluate both so you can see which one you prefer using.

[nctnico]

Judging from experience from others I wouldn't want the Tektronix MDO3000/MDO4000 series scope. The UI and decoding would be too slow.

May I ask which scope(s) you use and your experience with them?

I think I've owned about a dozen DSOs over the past decade or so. Currently I have a GW Instek GDS-2204E (4 channel 200MHz) and an Agilent DSO7104A (4 channel 1GHz).

GDS-2204E:
Pros: long memory (but not in all modes), versatile decoding triggering, long & fast FFT, easy to operate (seperate select button) and some features the DSO7104A doesn't have (like input filtering).
Cons: relatively small screen, does many operations in software so can get slow, FFT on whole memory so no 'gating'

DSO7104A:
Pros: big screen, high bandwidth, fast protocol decoding, digital channels, FFT on displayed data so some form of selecting data to analyse.
Cons: signals are noisy (but recent Keysight scopes are better), short memory, can be hard to operate due to the single select/push button, slow FFT

Even though these scopes are worlds apart they both have their strong points. I use the DSO7104A as my daily scope though but for an upcoming project the GDS2204E will be better suited. I honestly wouldn't know what scope to buy which has the strong points from both combined.

[FrankD]

... The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/


Thanks!

The SA works up to the scopes bandwidth.
You only need to pay extra for the SA if you need it's full bandwidth.( = for MDO3000, )

MDO4000 is extra $$$$
Main product page lists LA and AWG as optional but SA as 'up to 6GHz' on the crappy website.
http://www.tek.com/oscilloscope/mdo4000c-mixed-domain-oscilloscope
(the upgrade tab and configure and quote reveals the additional SA tax.)

[knights]

... The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/


Thanks!

The SA works up to the scopes bandwidth.
You only need to pay extra for the SA if you need it's full bandwidth.

My understanding is that this is true for the 3000 series scopes, but not for the 4000 series scopes. I was told that enabling the SA option in the MDO4024C is a separate option (the base model will not have it enabled - even to the BW of the scope).

[HighVoltage]

The Keysight 3000X scope will probably do everything as the the 4000X, but the 4000X has a bigger screen.

The Tektronix gets very slow, when you do any math or decoding or FFT.
The Keysight scopes are usually faster.
I am using the 2000X, 3000X, 6000X and 7000B series Keysight scope and I am very happy with them.
These days, I would not even consider any of the newer Tek scopes and every time I am using one, I am disappointed again.
 

[knights]

Spec wise I think the most obvious difference is that Tek has the SA and Keysight has a much faster sample rate.

Yes, but unfortunately you need to pay extra (something like $3000-4000) to have it enabled on the 4000 series scope. I've heard that the SA option on the 3000 series scope is a glorified port that is just switched into the ADC which runs an FFT. My guess is that the 4000 series scope has a much better SA which is why they want you to pay for it.

Specs aside I think the UI is very important and this is probably a matter of taste (I personally prefer Keysight). I would highly recommend asking your distributor to let you evaluate both so you can see which one you prefer using.

I am actually familiar with both Tek and Keysight (technically Agilent, at the time) scopes. I started learning on Tek scopes and am pretty comfortable with them. I thought they were great until I actually used an Agilent scope and noticed how slow the UI is. It's a shame because I like the way things are laid out on Tek scopes, but after noticing how slow they are, I started to enjoy using the Agilent scopes more.

[Neganur]

If memory serves, I think to recall that there was a significant difference in SA performance between the 3k and 4K Tek, with the 4K being the proper one.

EDIT: ah yes, you can't have both SA and time domain at once in the 3k. Only the 4K does that.

https://www.testequity.com/documents/pdf/MDO3000-MDO-DPO4000B-Comparison.pdf

[mk_]

... The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/


Thanks!

The SA works up to the scopes bandwidth.
You only need to pay extra for the SA if you need it's full bandwidth.

No. Search the forum for the script which activates all(!) options on the TEK MDO3xxx.

With all required options enabled price for the MDO3014 is ok, otherwise it is completly overpriced (compared with several LeCroys I use at customers site)

mk_

[knights]

... The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/


Thanks!

The SA works up to the scopes bandwidth.
You only need to pay extra for the SA if you need it's full bandwidth.

No. Search the forum for the script which activates all(!) options on the TEK MDO3xxx.

With all required options enabled price for the MDO3014 is ok, otherwise it is completly overpriced (compared with several LeCroys I use at customers site)

mk_

Does a script exist to enable the SA for the MDO4000 series scopes? That would be truly awesome and make it immediately worthwhile to go with Tek seeing as I am being quoted the same price for both at the moment.

[Wuerstchenhund]

that Tek has the SA

This is not a real SA!

The "SA" part in the Tek MDO is nothing like a real SA, it's pretty much just FFT as on every other scope. All Tek did was adding another high bandwidth input with N connector to their scopes. That 'SA' port goes to the same 8bit acquisition system the conventional analog inputs are connected to, and in 'SA' mode the scope performs 8bit FFT on parts of the sample data (1Mpts on the MDO3k, can't remember how much its on the MDO4k). As a result, the RF performance is abysmal, it's slow (like everything else on these scopes), and, unlike a real SA, because it's just FFT on a an old and slow scope platform (these are essentially just DPO3000/4000 scopes) there are various limitation regarding span and RBW. The only real advantage is that the additional port offers a much higher BW (3GHz/6Ghz, if you pay for it) than the analog BW of the scope, but considering how poor the SA part is I'd say the real-life advantage is negligible.

As stated in another thread, I have (again, because a colleague I gave it to brought it back) a MDO3054, and we had various MDO4000 models for evaluation and all have been slow and painful to use. Tek has come up with mediocre at best and often just poor DSOs since the days of analog scopes ended, and we now don't even consider them anymore unless one of our labs insists on including them (which is rare, and Tek never gets the business).

I'm not a huge fan of the Keysight DSOX because in my opinion it sacrifices too much for its excessive waveform update rate (which isn't as much as an advantage as Keysight makes you believe), primarily sample memory (4Mpts is a sad joke, and depending on what you do this even half or quarters so you might end up with 1Mpts) and functionality. Plus Keysight really squeezes people with their pricing (the DSOX are very expensive for what they are, even the expensive DSOX6004 is pretty much an entry-level scope platform). However, I'd take a DSOX4k over a Tek MDO any day, no hesitation.

BTW, just a word of warning as to "unlocking" options. That is generally tolerated for private users/consumers/hobbyists, but not when the scope is used in a role to earn money (i.e. a business). I don't know about Tek but Keysight, LeCroy and R&S keep records which scopes have which options enabled, from factory and after sale, and when an instrument comes back for service or calibration they tend to check if there are any illegitimate options enabled. And if they do find some then there are various outcomes, all of which are very unpleasant for the business that got caught using a hacked scope.

[FrankD]

... The built-in spectrum analyzer in the Tek scope is nice, but you have to pay extra for it :/


Thanks!

The SA works up to the scopes bandwidth.
You only need to pay extra for the SA if you need it's full bandwidth.

No. Search the forum for the script which activates all(!) options on the TEK MDO3xxx.

With all required options enabled price for the MDO3014 is ok, otherwise it is completly overpriced (compared with several LeCroys I use at customers site)

mk_

Does a script exist to enable the SA for the MDO4000 series scopes? That would be truly awesome and make it immediately worthwhile to go with Tek seeing as I am being quoted the same price for both at the moment.

Chances are that the key generator method is the same for the 4k model.
The script for the 3k doesn't list specific options for the 4k model .

I could not get the script working at first. (Never used python)
I may be wrong but I run into problems with the script as it needed an older version of python.

A little reverse engineering got it up and running:
I could verify the generated key for the SA option (was include in the deal) and the DVM option was an exact match with the official keys. The hack is reversible just by generating a new key or use the original string.

0x0000000002000000, "AERO", "Aerospace serial bus"
0x0000000004000000, "AUDIO", "Audio serial bus key"
0x0000000008000000, "AUTO", "Automotive serial bus"
0x0000000010000000, "AUTOMAX", "Full Automotive serial bus"
0x0000000020000000, "COMP", "Computer serial bus"
0x0000000040000000, "EMBD", "Embedded serial bus"
0x0000000080000000, "ENET", "Ethernet serial bus"
0x0000000100000000, "FLEX", "FlexRay serial bus"
0x0000000200000000, "USB", "USB serial bus"
0x0000004000000000, "LMT", "Limit/Mask test"
0x0000008000000000, "PWR", "Power analysis"

0x0000080000000000, "TRIG", "RF triggering"
0x0000040000000000, "VID", "HD and Custom Video"

0x0000800000000000, "CAL", "Calibration bit for manufacturing test"
0x0002000000000000, "BETA", "Beta release"
0x0004000000000000, "DEMO", "Internal demo unit"
0x0008000000000000, "DDU", "Distribution Demo Unit"

0x0000000000000001, "70MHz", "70MHz bandwidth"
0x0000000000000002, "100MHz", "100MHz bandwidth"
0x0000000000000004, "200MHz bandwidth", "200MHz"
0x0000000000000008, "300MHz", "300MHz bandwidth"
0x0000000000000010, "350MHz", "350MHz bandwidth"
0x0000000000000020, "500MHz", "500MHz bandwidth"
0x0000000000000040, "1GHz", "1GHz bandwidth"
0x0000000000000080, "2GHz", "2GHz bandwidth"

0x0000000000000200, "BW0T1", "Upgrade bandwidth from 70MHz to 100MHz"
0x0000000000000400, "Upgrade bandwidth from 70MHz to 200MHz", "BW0T2"
0x0000000000000800, "BW1T2", "Upgrade bandwidth from 100MHz to 200MHz"
0x0000000000001000, "BW1T3", "Upgrade bandwidth from 100MHz to 300MHz"
0x0000000000002000, "BW1T3", "Upgrade bandwidth from 100MHz to 350MHz"
0x0000000000004000, "BW1T5", "Upgrade bandwidth from 100MHz to 500MHz"
0x0000000000008000, "BW2T3", "Upgrade bandwidth from 200MHz to 350MHz"
0x0000000000010000, "BW2T5", "Upgrade bandwidth from 200MHz to 500MHz"
0x0000000000020000, "BW3T5", "Upgrade bandwidth from 300MHz to 500MHz"
0x0000000000040000, "BW3T5", "Upgrade bandwidth from 350MHz to 500MHz"
0x0000000000080000, "BW1T10", "Upgrade bandwidth from 100MHz to 1GHz"
0x0000000000100000, "BW2T10", "Upgrade bandwidth from 200MHz to 1GHz"
0x0000000000200000, "BW3T10", "Upgrade bandwidth from 350MHz to 1GHz"
0x0000000000400000, "BW5T10", "Upgrade bandwidth from 500MHz to 1GHz"

0x0000000400000000, "DVM", "Digital Voltmeter"
0x0000000800000000, "AFG", "Arbitrary Function Generator"
0x0000001000000000, "MSO", "Mixed Signal Oscilloscope"
0x0000002000000000, "SA", "Spectrum analyzer maximum input frequency"
0x0000000000000100, "SEC", "Security lockout"

The hex option string can be calculated by combining the options above
-----------------------------------------------------------------------

0x0000000400010000 = U500Mhz + DVM -> 'kkkkk-eeeee-yyyyy-ggggg-eeeee-n'

0x0000000000000020 = 500MHz
0x0000000400000000 DVM
0x0000000800000000 AFG

0x0000000C00000020 500 + DVM +AFG -> 'kkkkk-eeeee-yyyyy-ggggg-eeeee-n'

Run module gen.py in Python. Run following code as command line

tek.key.encode("MDO3xxx", "serialno", 0x000000DFFE000020) outputs key.
= All options excluded SA

[FrankD]

that Tek has the SA

This is not a real SA!

The "SA" part in the Tek MDO is nothing like a real SA, it's pretty much just FFT as on every other scope. All Tek did was adding another high bandwidth input with N connector to their scopes. That 'SA' port goes to the same 8bit acquisition system the conventional analog inputs are connected to, and in 'SA' mode the scope performs 8bit FFT on parts of the sample data (1Mpts on the MDO3k, can't remember how much its on the MDO4k). As a result, the RF performance is abysmal, it's slow (like everything else on these scopes), and, unlike a real SA, because it's just FFT on a an old and slow scope platform (these are essentially just DPO3000/4000 scopes) there are various limitation regarding span and RBW. The only real advantage is that the additional port offers a much higher BW (3GHz/6Ghz, if you pay for it) than the analog BW of the scope, but considering how poor the SA part is I'd say the real-life advantage is negligible.

As stated in another thread, I have (again, because a colleague I gave it to brought it back) a MDO3054, and we had various MDO4000 models for evaluation and all have been slow and painful to use. Tek has come up with mediocre at best and often just poor DSOs since the days of analog scopes ended, and we now don't even consider them anymore unless one of our labs insists on including them (which is rare, and Tek never gets the business).

I'm not a huge fan of the Keysight DSOX because in my opinion it sacrifices too much for its excessive waveform update rate (which isn't as much as an advantage as Keysight makes you believe), primarily sample memory (4Mpts is a sad joke, and depending on what you do this even half or quarters so you might end up with 1Mpts) and functionality. Plus Keysight really squeezes people with their pricing (the DSOX are very expensive for what they are, even the expensive DSOX6004 is pretty much an entry-level scope platform). However, I'd take a DSOX4k over a Tek MDO any day, no hesitation.

BTW, just a word of warning as to "unlocking" options. That is generally tolerated for private users/consumers/hobbyists, but not when the scope is used in a role to earn money (i.e. a business). I don't know about Tek but Keysight, LeCroy and R&S keep records which scopes have which options enabled, from factory and after sale, and when an instrument comes back for service or calibration they tend to check if there are any illegitimate options enabled. And if they do find some then there are various outcomes, all of which are very unpleasant for the business that got caught using a hacked scope.

This might be true for the 3k which is not multi domain( It is a very basic SA but it is far superior to it's fft math)
The 4k is able to display four channels plus the signal from the SA input simultaneously so it must have dedicated hardware for the sa channel.

For business use a hacked scope is a no go.  For some extended evaluation it could be handy though to try out an upgrade option before buying.

[knights]

That 'SA' port goes to the same 8bit acquisition system the conventional analog inputs are connected to, and in 'SA' mode the scope performs 8bit FFT on parts of the sample data (1Mpts on the MDO3k, can't remember how much its on the MDO4k). As a result, the RF performance is abysmal, it's slow (like everything else on these scopes), and, unlike a real SA, because it's just FFT on a an old and slow scope platform (these are essentially just DPO3000/4000 scopes) there are various limitation regarding span and RBW.

Is this true for both the 3000 and 4000 series scopes? My understanding was that the 4000 series scope's SA has much better performance. I guess having time-correlated frequency signals on one display is a nifty feature for sure - but if what you're saying is true, it seems that just buying a stand-alone SA would offer much better performance for the price you would pay.

I'm not a huge fan of the Keysight DSOX because in my opinion it sacrifices too much for its excessive waveform update rate (which isn't as much as an advantage as Keysight makes you believe), primarily sample memory (4Mpts is a sad joke, and depending on what you do this even half or quarters so you might end up with 1Mpts) and functionality. Plus Keysight really squeezes people with their pricing (the DSOX are very expensive for what they are, even the expensive DSOX6004 is pretty much an entry-level scope platform). However, I'd take a DSOX4k over a Tek MDO any day, no hesitation.

I tried contacting LeCroy's distributors (if I recall, you are a strong advocate of their scopes!) but was very disappointed with their response time. It took them 3 weeks just to respond to my initial quote request, and then during the demo, the representative did not even know how to operate the scope! I had to help with the setup and configuration and it was my first time using it! I was not reassured with the service or support we would get after making a purchase, and their scopes were quoted at a much higher price. The Wavesurfer 3000 was approximately $5500 CAD (without any protocol decoding bundles).

Which scopes would you recommend I consider in the future (and are they in a similar price range - CAD $6000 - to what I'm being offered currently)?

BTW, just a word of warning as to "unlocking" options. That is generally tolerated for private users/consumers/hobbyists, but not when the scope is used in a role to earn money (i.e. a business). I don't know about Tek but Keysight, LeCroy and R&S keep records which scopes have which options enabled, from factory and after sale, and when an instrument comes back for service or calibration they tend to check if there are any illegitimate options enabled. And if they do find some then there are various outcomes, all of which are very unpleasant for the business that got caught using a hacked scope.

Thanks for mentioning this. I definitely do not want to run into any legal issues as this scope is being used for official business purposes!

[tautech]

I tried contacting LeCroy's distributors (if I recall, you are a strong advocate of their scopes!) but was very disappointed with their response time. It took them 3 weeks just to respond to my initial quote request, and then during the demo, the representative did not even know how to operate the scope! I had to help with the setup and configuration and it was my first time using it! I was not reassured with the service or support we would get after making a purchase, and their scopes were quoted at a much higher price. The Wavesurfer 3000 was approximately $5500 CAD (without any protocol decoding bundles).

That's truly abysmal. How does a reseller like that even get to represent any test equipment brand. 

In your case it might be wise to asses the support and response of any of your local dealers and then focus on what they've got to offer.
Then there's the recent PSU problems with Keysight's that you need to consider and be sure to obtain an extended warranty as they can apparently fail just outside normal warranty.

Yep, it's a minefield out there. 

[knights]

I tried contacting LeCroy's distributors (if I recall, you are a strong advocate of their scopes!) but was very disappointed with their response time. It took them 3 weeks just to respond to my initial quote request, and then during the demo, the representative did not even know how to operate the scope! I had to help with the setup and configuration and it was my first time using it! I was not reassured with the service or support we would get after making a purchase, and their scopes were quoted at a much higher price. The Wavesurfer 3000 was approximately $5500 CAD (without any protocol decoding bundles).

That's truly abysmal. How does a reseller like that even get to represent any test equipment brand. 

The representative explained that they were not familiar with the lower models of their scopes as they are used to selling all of their fancy 60 GHz + equipment. I suppose that's understandable, but it definitely does not inspire confidence during the first meeting with a prospective client!

In your case it might be wise to asses the support and response of any of your local dealers and then focus on what they've got to offer.
Then there's the recent PSU problems with Keysight's that you need to consider and be sure to obtain an extended warranty as they can apparently fail just outside normal warranty.

Yep, it's a minefield out there. 

Oh wow, I haven't even heard of this issue. Do you have any links/sources for this? This is the equipment list I'll likely be settling on, by the way:

Keysight DSOX4024A Oscilloscope (with DSOXAPPBNDL included)
Keithley 2231-30-3 DC Power Supply
Keysight 34461A 6.5 Digit DMM
Tektronix AFG1022 Function Generator

I hope I won't run into any issues!

[tautech]

First one must say that forum member Daniel from Keysight beavered behind the scenes to appease their customer however it should have never come to that should the local dealer have been more supportive of their customer.

It was with a 2kA model and if you have a hunt within the forum you can find the 13 page thread.
It got a bit heated as these thing do so the OP finished by offering his thanks to Daniel in this thread:
https://www.eevblog.com/forum/testgear/thank-you-daniel-my-faith-in-agilent-keysight-has-been-restored-)/

[TheSteve]

I'm not aware of any power supply issue with the Keysight scopes. There were some 2000s and 3000s that suffered from corrupted flash images though. The latest firmware version has changes to help with the problem according to Daniel(from Keysight).

knights - that is a great collection of gear that should serve the company well, also Keysight has great warranty support in Canada on the off chance you ever need to use it.

[Wuerstchenhund]

Is this true for both the 3000 and 4000 series scopes? My understanding was that the 4000 series scope's SA has much better performance.

The MDO4k is slightly better but it's still not a "real" SA but merely an extra high BW input that feeds into the scope's normal 8bit acquisition system for FFT (with the SA option enabled you lose the 4ch 5GSa/s mode, i.e. it's still 5GSa/s in 1 and 2ch mode but only 2.5GSa/s in 4ch mode as the rest goes to the SA). It's still 8bit resolution, and a (for an SA) pretty poor timebase stability.

I guess having time-correlated frequency signals on one display is a nifty feature for sure - but if what you're saying is true, it seems that just buying a stand-alone SA would offer much better performance for the price you would pay.

Don't forget that you can get TD on some standalone SA's as well, which in split mode would give you a time-correlated image of the waveform and the spectrum.

I tried contacting LeCroy's distributors (if I recall, you are a strong advocate of their scopes!) but was very disappointed with their response time. It took them 3 weeks just to respond to my initial quote request, and then during the demo, the representative did not even know how to operate the scope! I had to help with the setup and configuration and it was my first time using it! I was not reassured with the service or support we would get after making a purchase, and their scopes were quoted at a much higher price. The Wavesurfer 3000 was approximately $5500 CAD (without any protocol decoding bundles).

Yeah, that's bad. But I have a certain dislike for distributors anyways (I hate them as they rarely provide any benefit for their piece of the cake, and I get better offers from the manufacturers directly) so that's not completely surprising. My experience with the Canadian market is limited, but I'd always recommend to go through the manufacturer, which should either deal with you directly or kick one of its distributors into action. Also, don't confuse the laziness of some of the leeches (distributors) with what you can expect as product support which comes from the manufacturer, which pretty much all big brands (except Tek) deliver to a very high standard. LeCroy is no exception and in fact offers some of the longest support periods in the industry. Plus they provide software maintenance much longer than anyone else, including Keysight.

In terms of scope, the WS3000 sounds like a fitting candidate. The 200Mhz 4ch version should be around $3800 (that's USD). In practice you also shouldn't really have to pay extra for the decode options. Like other big brands, LeCroy regularly offers ex-demo scopes (which tend to come with all options) with discounts of up to 45%.

Which scopes would you recommend I consider in the future (and are they in a similar price range - CAD $6000 - to what I'm being offered currently)?

CAD6k is roughly US$4500. That should buy you a 200Mhz 4ch WS3024 and still leaves you with some money to spend on other things (i.e. active probe). With some luck that might even buy you a 500MHz 4ch ex-demo WS3054.

One last bit of advice: don't decide on a scope on what you read here or what the spec sheet say. Get loaners of all scopes that you consider in your lab and give them a spin around the block (even the Tek MDO4k, who knows, maybe you're one of the three people in the world who like them  ), and then decide which one to buy.  Never spend what by any standard is a significant amount of money on test gear without having a test drive. After all, at the end of the day *you* and your colleagues have to feel comfortable with the scope and its capabilities.

[Wuerstchenhund]

that Tek has the SA

This is not a real SA!

The "SA" part in the Tek MDO is nothing like a real SA, it's pretty much just FFT as on every other scope. All Tek did was adding another high bandwidth input with N connector to their scopes. That 'SA' port goes to the same 8bit acquisition system the conventional analog inputs are connected to, and in 'SA' mode the scope performs 8bit FFT on parts of the sample data (1Mpts on the MDO3k, can't remember how much its on the MDO4k). As a result, the RF performance is abysmal, it's slow (like everything else on these scopes), and, unlike a real SA, because it's just FFT on a an old and slow scope platform (these are essentially just DPO3000/4000 scopes) there are various limitation regarding span and RBW. The only real advantage is that the additional port offers a much higher BW (3GHz/6Ghz, if you pay for it) than the analog BW of the scope, but considering how poor the SA part is I'd say the real-life advantage is negligible.

This might be true for the 3k which is not multi domain( It is a very basic SA but it is far superior to it's fft math)

It *is* the same as it's FFT math. I know because I have a MDO3K here. The only difference is FFT math only uses the analog channels and is therefore limited to the analog scope BW. That's it. There's nothing that's "far superior" in the SA part, only in your mind.

The 4k is able to display four channels plus the signal from the SA input simultaneously so it must have dedicated hardware for the sa channel.

No, it doesn't. It's the same scam principle as on the MDO3k. The reason the MDO4k can run scope and SA simultaneously is because it has more spare capacity in it's acquisition system (4x 5GSa/s on the MDO4k vs 4x 2.5GSa/s on the MDO3kA <1GHz). The MDO4k can run all four channels at 5GSa/s (one ADC per channel) unless the SA option has been enabled after which the sample rate drops to 2.5GSa/s in 4ch mode (2 ADCs for scope, 2 ADCs for SA).

BTW: fixed your full quote

[Wuerstchenhund]

This is the equipment list I'll likely be settling on, by the way:

[...]
Tektronix AFG1022 Function Generator

There's a chance to save quite a bit of money by buying the original instead of the rebadge

http://www.owon.com.hk/products_info.asp?ProID=177#sthash.P9MhxxHH.dpbs