EEVblog #892 - Siglent SSA3021X Spectrum Analyser Teardown

[EEVblog]

A very detailed look inside the new Siglent SSA3021X 3.2GHz Spectrum Analyser.
The entire RF section is broken down and analysed in depth with a block diagram overlay.

[jancumps]

You may also have broken down youtube. There are playback errors.

The error is very representative for a teardown video error thoug.

[Pinkus]

Very nice. Thank you.
May I ask for some high-res photos also from TG and main processor board?
Interesting to see on the upper right sight: an SD card connector and an unpopulated FPC connector with a missing TSSPO chip. My guess: the latter could be for a planned and/or optional (though resistive) touch panel cable with touch screen controller?
Thx

[EEVblog]

May I ask for some high-res photos also from TG and main processor board?

Yes, will upload tomorrow.

[System Error Message]

Would really like to see this in action, do you think you could do a video of it?

edit: nevermind just found it in a comparison video. Its just unboxing and teardown videos without any action have become too common.

[retrolefty]

The teardown was great. Sure seems like a whole lot of SA for the price point. I don't need a SA but I've always dreamed of owning one. 

[Laertes]

I gotta say, the format you chose for this teardown is great! It seems you took a bit of a page from Shahriars/The Signal Paths book there, with the block diagrams and the photos with overlay, each individual block explained in depth etc.
Excellent work

Though I do imagine it's a lot more work than just dicking around with your pointer straight on the actual board...

[tautech]

Would really like to see this in action, do you think you could do a video of it?

edit: nevermind just found it in a comparison video. Its just unboxing and teardown videos without any action have become too common.

Relevant threads:
https://www.eevblog.com/forum/blog/eevblog-891-siglent-ssa3021x-vs-rigol-dsa815-spectrum-analyser/
https://www.eevblog.com/forum/testgear/comparison-rigol-dsa815-tg-with-siglent-ssa3021x-spectrum-analyzer/
https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/
https://www.eevblog.com/forum/testgear/hack-of-sigllent-spectrum-analyzer-ssa3021x/

Manufacturers website:
http://www.siglent.com/ENs/pdxx.aspx?id=1299&T=2&tid=18

[G0HZU]

At 23:32 in the video the function of the first RF switch U1 is to switch in the overload dummy load R1 (via C9) if there is an overload.

i.e. if there is a large overload the analyser can simply divert the RF input to the big 49.9R resistor R1.

The input blocking cap C10 is likely to be a big value possibly as big as 1uF. This can obviously store a lot of energy (for a given charge voltage) compared to a regular RF cap down in the nF range so I would expect to see something to protect the front end from transients from this cap if DC is ever applied/removed at the analyser input. Maybe those clamping diodes help here but it's hard to see how they are configured.

[G0HZU]

The second SOT23-6 RF switch U2 at 24:06 looks like it allows an internal test signal to be switched in to the front end of the analyser. Possibly for self testing/calibration purposes. The opamp IC to the right of it is probably something to do with the RF overload detection. Possibly a crude diode detector/comparator/trip to control that first RF switch U1 that switches in the (overload) dummy load resistor R1.

The input switches U1 and U2 look quite feeble in the SOT23-6 package but they are probably rated to about 1W and probably a bit more before they actually get damaged. So U1 can probably dump something in the ballpark of 1W into R1 if there is a bad overload. But much more than this and something is going to release some magic smoke somewhere...

[altaic]

Dave, I really liked the front-end breakdown and explanation of the block diagram!

As people mentioned in the thread for the previous video, it'd be great to have a fundamentals friday explaining how SAs work and what each stage of the front-end does to the input signal to do the business. Actually, a video series on analog front-ends in general would be awesome-- you've already done one on multimeters; 'scopes and SAs to come?

[AF6LJ]

By the way Dave;
The common way to pick off signals for sampling is to use a directional coupler.
Their PCB implimentation of a directional coupler is tried and true. They look like 10DB couplers. IF I had to put a number on it.
Good job on the teardown.
One of your very best RF teardowns yet...


 
 

[Someone]

Daylight = 500THz

Terahertz

[AF6LJ]

Daylight = 500THz

Terahertz

Yup

[tszaboo]

I really liked the added effort for this RF equipment. It was too often: "Look RF voodoo and strange looking antennas!". OK, not really, but almost. This was very good.

[bitseeker]

Best teardown, Dave. The extra time investment clearly shows and the level of detail is appreciated.

[richnormand]

Really appreciated this tear-down and analysis with the diagrams and the board walkthrough of the various stages.
Cheers and thanks Dave.

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

[tautech]

Really appreciated this tear-down and analysis with the diagrams and the board walkthrough of the various stages.
Cheers and thanks Dave.

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

Dave has a reputation for teardowns so any manufacturer shouldn't be at all surprised that he did.

Don't want a teardown and exposure of your design to the world ..... then don't send it to Dave, simple.

[nctnico]

From what I have seen from the teardown there is nothing Siglent should be ashamed off. However the hardware engineers at Siglent should go after their co-workers in the software department with pitch forks more often to make them do a good job as well 

[richnormand]

From what I have seen from the teardown there is nothing Siglent should be ashamed off.

Fully agree. At this price point this is excellent work.

[EEVblog]

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

I just got an email from Siglent, they loved the teardown.

[bitseeker]

That excellent, Dave. Now, how can we use that knowledge to work for us?

[AF6LJ]

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

I just got an email from Siglent, they loved the teardown.

Good Deal 

[coppice]

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

I just got an email from Siglent, they loved the teardown.

They might have liked it less if you'd done a parallel teardown of the 3.2GHz model, and found the hardware was identical.

[tautech]

PS: considering the comments on the last video comparing the two SP and the fact you did not have it for long I wonder what are the reactions from Siglent on the level of design detail given as well as just opening it?

I just got an email from Siglent, they loved the teardown.

They might have liked it less if you'd done a parallel teardown of the 3.2GHz model, and found the hardware was identical.

We already know it is.