Author Topic: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser  (Read 26232 times)

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Offline rf-loop

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #25 on: June 21, 2016, 07:20:35 am »
Just a remark about the delta markers. When you take a 'difference' in dB's between two values (ie a ratio) the unit disappears. Eg the 'difference' between 23 dBm and 13 dBm is 10 dB. Likewise the difference between -100 dBm/Hz and -120 dBm/Hz is 20 dB.

It seems the Rigol takes the ratio of the powers and then divides by the RBW. For example at 24:23 I read 0 dBm and -67 dBm. the ratio would be -67 dB. Dividing by the RBW results in -87 dB/Hz.

However in my view the only point where this would make sense is when the reference marker is at the peak (as in your case). For any other point except that special case the Siglent way (just dB) is more generic. For example if I would want to compare the noise floor at two points, supposing there is a -10 dB ratio between the two powers, I would rather read -10 dB, than -30 dB/Hz. This latter value would not make any sense to me.

That makes sense. But if you put the marker in noise mode it should know this and give you the correct units of measurement you expect IMO.

Errr....

This is good that there read: IMO.

 :-DD

7 points wink: User need know whhat he is doing. Equipment can not know.

Is it better that you do some day one "teaching hour" Video where you explain Normalization to 1Hz, dBc/Hz and then NOISE dBm/Hz and importantly if you use noise cursors for look noise level dBm normalised to 1Hz noise BW.
It is not at all simple game. If we take (sinusoidal type) peak dBm level what we look with 100Hz RBWa filter. We can normalize it to 1Hz RBWb same kind of signal using same kind of RBW shape factor just using 20dB subtract. (10 *  log (RBWaHz/RBWbHz)
With random noise situation is bit different.
Random wideband noise  have Gaussian distribution, but here with RBW filter noise have Rayleigh distribution.
Also just sidenote: Many times VideoAverage Detector can not measure signal peak level so using example two (noise mode) markers for different kind of signal comparing drops user to trap very easy.

How machine can know what signal is under your marker position. This is what user need know. And USER NEED do Right selections/settings. But this need knowledge.

Proper using SA's for measurements need knowledge about basic fundamentals  -- and also user need know his equipment. Tjis is why old times you buy expensive tool HP give also free teaching and training courses some time times and in lab, only peoples who have get training for equipment have access to use it. Also there was available quite deep explanation about theory of operation.

In other way we need every day wonder what hell results user get and are these results valid or total bullshits what we then discuss about why my equipment display so strange things. But, of course this we need also and this is (mostly) useful for lot of peoples who are curious and always willing to learn more - and this is least one reason why I have been hobbyist with electronics over 50 years and never get enough. 
Out from box and then wondering this and that and oh my god this value or that figure is strange or wrong or is my equipment broken.
We have seen it with all equipments, here and there and everywhere.

For todays SA's this AN-150 is nearly as Mandatory reading. (It also tell how Siglent works in principle)

And very importantly if you are bit new with SA's and/or worked lot of with analog sweeping SA's and full digital IF Sweep/FFT SA is new for user.

Btw: Chapter 5 pages 46 - 54  explain these noise things.




« Last Edit: June 21, 2016, 08:31:41 pm by rf-loop »
If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
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Online coppice

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #26 on: June 21, 2016, 01:52:46 pm »
In China Siglent list 1.5GHz models - SSSA3015X and SSA3015X-TG -  but western sites selling Siglent don't seem to be offering these.
 

Offline SeanB

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #27 on: June 21, 2016, 07:37:27 pm »
I was laughing so much with the "Come on, while I'm still young" with the booting. Had to take a 5 minute break just to get over that..........
 

Offline AF6LJ

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #28 on: June 21, 2016, 08:41:13 pm »
I was laughing so much with the "Come on, while I'm still young" with the booting. Had to take a 5 minute break just to get over that..........
That was funny as hell, made me wonder if that thing had a 80286-16 under the hood
Sue AF6LJ
Test Equipment Addict, And Proud Of It.
 

Offline BobC

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #29 on: June 21, 2016, 10:02:20 pm »
+1 for rf-loop's recommendation for a Fundamentals Friday video on spectrum analysis in general, and reference measurements in particular.

Perhaps 2 videos: First one for the what these measurements are and how to make them (theory + how implemented in test equipment).  Second one for which is needed when and why (application and mis-application).

AN-150 is truly excellent, but may be a bit advanced for some.  Perhaps a primer to get folks ready to plow through AN-150 on their own?
 

Offline ElectricGuy

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #30 on: June 21, 2016, 11:48:17 pm »
+1 for rf-loop's recommendation for a Fundamentals Friday video on spectrum analysis in general, and reference measurements in particular.


+1
Thank you!
Regards
ElectricGuy
 

Offline f4eru

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #31 on: June 22, 2016, 08:36:38 pm »
hmm. 2.1 GHz ? Seriously, Siglent ????
why not 2.5 GHz ? coz, you know, 2.4 is a very very common band, and people actually do want to measure it. Go figure...

Concerning the menu : it is the same because every specan is the same since 15 Years. Or they all copied R&S and Agilent, since 15 Years, if you prefer.
« Last Edit: June 22, 2016, 08:39:32 pm by f4eru »
 

Offline bitseeker

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #32 on: June 23, 2016, 03:02:23 am »
why not 2.5 GHz ? coz, you know, 2.4 is a very very common band, and people actually do want to measure it. Go figure...

Because they want those people to buy the 3.2 GHz model, of course. >:D
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Offline Smokey

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #33 on: June 23, 2016, 05:06:05 am »
All of your reference signals need to be at 1.21GHz
 

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #34 on: June 23, 2016, 05:23:43 am »
All of your reference signals need to be at 1.21GHz

Damn, yes!
 
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Offline DL5TOR

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #35 on: June 23, 2016, 02:08:30 pm »
All of your reference signals need to be at 1.21GHz

Damn, yes!

But then please with 121 dBm (do the Math  :-BROKE )
 

Offline altaic

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #36 on: June 23, 2016, 07:05:00 pm »
All of your reference signals need to be at 1.21GHz

Damn, yes!

Correctly pronounced "one point twenty-one jigahertz!"

Also, you should make a version of O0 with white hair for the Doc.
« Last Edit: June 23, 2016, 07:14:17 pm by altaic »
 

Offline bitseeker

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #37 on: June 23, 2016, 07:43:08 pm »
Also, you should make a version of O0 with white hair for the Doc.

+1 ^-^
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Offline Brumby

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #38 on: June 24, 2016, 12:07:33 am »
All of your reference signals need to be at 1.21GHz

Damn, yes!

But then please with 121 dBm (do the Math  :-BROKE )

I did wonder about the power level.  Thank you for that detail.   ;)
 

Offline Smokey

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #39 on: June 24, 2016, 12:42:21 am »
All of your reference signals need to be at 1.21GHz

Damn, yes!

But then please with 121 dBm (do the Math  :-BROKE )

88dBm!!!!!!  You'll see some serious shit!
 

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #40 on: June 24, 2016, 02:10:33 am »
88dBm!!!!!!  You'll see some serious shit!

Some serious shit is about to happen!
« Last Edit: June 24, 2016, 02:17:11 am by EEVblog »
 
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Offline Smokey

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #41 on: June 24, 2016, 04:41:55 am »
Actually we must be in the future... because it appears Siglent made a piece of gear that isn't total crap. 
 

Offline bitseeker

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #42 on: June 24, 2016, 05:40:31 am »
Wow, you just about got to 88!
I TEA.
 

Offline kalleboo

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #43 on: June 24, 2016, 10:07:21 am »
Some serious shit is about to happen!
Well you *did* go back in time 16 years!
 

Offline IshtarTor

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #44 on: June 25, 2016, 06:30:00 am »
If you insist on buying new but the way I see it the choice usually is between used A-brand (with warranty) or new B-brand if you are on a budget. And then the story is completely different. If I take my Advantest SA as an example (again): the Rigol and Siglent are in the same price range of what I paid for my Advantest SA including a 1 year warranty.

Used spectrum analyser in Australia cost a fortune. Shipping is a killer as you almost always have to import them.
Interestingly, Tektornix and R&S have interesting entry level analyzers.

http://www.testequity.com/products/5286/
http://www.testequity.com/products/5286/

Still twice as expensive as the chinese brands, but the Tek has a 6GHz BW.
Actually we must be in the future... because it appears Siglent made a piece of gear that isn't total crap.
Their sig gen is not bad at all. And the chinese brands fill a price market that simply didn't exist before. Spectrum analyzers were simply a dream for many very small companies and individuals.
« Last Edit: June 25, 2016, 06:34:40 am by IshtarTor »
 

Offline MasterTech

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #45 on: June 25, 2016, 11:07:07 am »
If you insist on buying new but the way I see it the choice usually is between used A-brand (with warranty) or new B-brand if you are on a budget. And then the story is completely different. If I take my Advantest SA as an example (again): the Rigol and Siglent are in the same price range of what I paid for my Advantest SA including a 1 year warranty.

Does your Advantest have TG? If so please post the response of it, I hope its not as 'good' as the R3361A:

http://www.fatpigdog.com/Advantest_R3361A/R3361A.htm
« Last Edit: June 25, 2016, 11:10:39 am by MasterTech »
 

Offline rf-loop

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #46 on: June 25, 2016, 11:22:48 am »
If you insist on buying new but the way I see it the choice usually is between used A-brand (with warranty) or new B-brand if you are on a budget. And then the story is completely different. If I take my Advantest SA as an example (again): the Rigol and Siglent are in the same price range of what I paid for my Advantest SA including a 1 year warranty.

Does your Advantest have TG? If so please post the response of it, I hope its not as 'good' as the R3361A:

http://www.fatpigdog.com/Advantest_R3361A/R3361A.htm

Do it have function: "Normalize" ?
If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
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Offline smarteebit

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #47 on: July 02, 2016, 07:20:23 am »
88dBm!!!!!!  You'll see some serious shit!

Some serious shit is about to happen!


??? Cannot understand it. Is it an intrinsic spur? Or there is some story in it?
 

Offline tautech

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #48 on: July 02, 2016, 08:02:16 am »
88dBm!!!!!!  You'll see some serious shit!

Some serious shit is about to happen!


??? Cannot understand it. Is it an intrinsic spur? Or there is some story in it?
Yes and yes.

For very detailed technical explanation go to your local video store and hire/by "Back to the Future" movie.
Study in great detail for mentions of GHz.  ;)
Avid Rabid Hobbyist
 

Offline rf-loop

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Re: EEVblog #891 - Siglent SSA3021X vs Rigol DSA815 Spectrum Analyser
« Reply #49 on: July 02, 2016, 08:20:18 am »
88dBm!!!!!!  You'll see some serious shit!

Some serious shit is about to happen!



??? Cannot understand it. Is it an intrinsic spur? Or there is some story in it?

88 dBm power is over 630kW
 :-DD

But also if you see DL5TOR comment:
Quote
But then please with 121 dBm (do the Math  :-BROKE )

« Last Edit: July 02, 2016, 10:05:20 am by rf-loop »
If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
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