TSP #75 - Tektronix TSG4106A RF Signal / Vector Generator Review, Teardown & Experiments

In this episode Shahriar presents a detailed review of the new Tektronix TSG4106A RF Signal / Vector Generator. The key features are:
True DC to 2 GHz, 4 GHz or 6 GHz to support both analog and vector/digital signal generation.
Typical ≤±0.30 dB amplitude accuracy (0 dBm CW signal at 22 ºC) from 10 MHz to 6 GHz.
I/Q modulation inputs (400 MHz RF bandwidth).
ASK, FSK, MSK, PSK, QAM, VSB, and custom I/Q.
A complete teardown of the unit is presented along with an explanation of various functions, components and sub-systems. The basic unit performance is verified using a Keysight EXA Signal Analyzer. The TSG4106A is then used to along with an Analog Devices I/Q de-modulator whose output is examined for performance verification.
The Signal Path Blog
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[@wadehsu2347]

The reason for those closely spaced crystals is to use them as a filter. The PLL only work in integer-N mode to eliminate phase noise introduced by the fractional-n modulated divider. In order to keep the clock divider small to achieve a large loop bandwidth thus reduce close-in phase noise some of the tuning resolution in the PLL synthesizer is sacrificed. This is compensated by the DDS generated variable references clock that ultimately feed the PLL. However, the DDS output directly is not a good enough clock source due to jitter and spurs. So the crystal are configured as VCXO and lock to the output frequency of the DDS to be used as a high-Q filter. This way you get a very clean and low spur reference frequency that has a tuning resolution of 2^48. The different frequency of the crystal is due to the tuning range of the VCXO which is typically

[@Thesignalpath]

Excellent!

[@Pieh0]

Damnit KZbin, process the 1080p stuff first, 360p is potato land

[@Moonblade042194]

+Pieh0 POOOOTATOOOEEE

[@jasonmichaeljones]

thanks for the video as always.. I was really hoping for a peek into that RF section at the end.. you freaking tease! :)

[@wadehsu2347]

The reason you see the SRS OCXO in there is because SRS actually design and manufacture the RF part of this generator. Even the main board has SRS p/n on it. Tektronix took that RF front end and put their own user interface on it and sell it for trice the price. Admittedly, the tektronix's UI is much better then the SRS one. The SMA connector on the RF can is most likely to drive a doubler that is an option on the SRS SG380 series signal generator. If you look up the version of this instrument from SRS, the spec is essentially the same with exactly the same SSB phase noise characteristics and they even have an option to add a Rb atomic standard into the generator to give you even better frequency stability.

[@friedmule5403]

4:05 They cost about $4,000 - $11,000 used in 2021, else a fantastic interesting unit and great review as always! :-)

[@AdvayMengle]

He's talking about jusrt the oscillator part being a few hundred dollars :P

[@friedmule5403]

@@AdvayMengle I have no doubt that he is telling the truth and is getting the things to the prize he says, I do also think he has to be amazingly talented in finding these offers. I have been lucky to ave a few hundred, but not several thousands like he is normally able to! :-)

[@qasimvirk4643]

iss cheez k nahin tha pata thankx yaar aap kii video daikhi tu pata chl gya tha

[@voltlog]

As usual a very nice in depth review! Thank you!

[@Tom-dn5de]

@ The Signal Path Thank you so much! It’s a great video again, I have a question that is not relative to this video. I am reading the Specifications and Performance Verification of TSG4106A, I understand most of the parts but “Output level accuracy (IQ modulation relative to CW)” part (on page 21). Even I have tried to read some papers relative to IQ modulation but I still can not get it. If you get a chance, could you please explain it to me? download.tek.com/manual/TSG4100A-Series-RF-Signal-Generator-Specifications-Performance-Verification-Technical-Reference.pdf

[@mikeselectricstuff]

Noticed SRS on the main PCB - have Tek badged the whole design from them?

[@MrCapacitator]

+mikeselectricstuff Looks like it, I think I can just make out SRS on some of the other boards too and interestingly they also have the date Jan 2013 on them, so looks like at least some of the hardware has been ready for 3 years.

[@megabytephreak]

+MrCapacitator The back panel layout looks identical to the SRS SG390 series, which also includes a 6 GHz model.

[@MrCapacitator]

+megabytephreak Yep certainly appears to be a badge engineered SG390 with just a different front panel

[@AdvayMengle]

@@MrCapacitator So what does one get buying this for 20k, vs the 6GHz SG390 for 10k?

[@dubzthegiant7562]

Very thorough review and interesting review. I've always wondered how long it takes for you to do the review of these products, including research of parts (if required, wouldn't surprise me if you've memorized many part numbers and specs), the review itself, and post prod stuff?

[@PlasmaHH]

Have you ever considered investing in a second camera so you can do a cropped overlay of one instrument over another view?

[@garybevis8691]

Great video as always, I am surprised at Tek, for $14,000 when you dial up 16.0dB @ 6.000000000GHz you should get 16.0dB! Wow, according to the comments this is a rebranded Stanford Research SG390, Tek has really changed, sad. When they used other teams stuff, like Sony Tektronix, they would put it on the label. Maybe Stanford Research doesn't want the association.

[@alextrofimov7947]

Seems like a good idea to have a fan deep inside the unit. The noise may be significantly less.

[@user-vl2pk5go2w]

Hello,What software are you using on your laptop?About the 27th minute of the video.

[@michaelhawthorne8696]

That's a nice review/tear down . I would like to say I followed along but was lost relatively early. QAM's, no idea what they are. I dealt with QPSK modulators in the 80's at GEC UK. How many years did you stay in university to gain this knowledge? I wish I went to Uni after completing my City and Guilds... Damn it I even got the best results for the course in that subject (Electronics) Some call this "summa cum laude" although that might be stretching a point...lol Going to GEC from college may have been a bad idea.....

[@Thesignalpath]

+Michael Hawthorne Learning is never-ending. I'll try to do some tutorials on QAM.

[@michaelhawthorne8696]

+The Signal Path Blog Great, Thanks.... Looking forward to that.

[@AureliusR]

+Michael Hawthorne Google Quadrature Amplitude Modulation. It's not as hard as it looks. Very ingenious way to cram more data into a particular bandwidth, at the cost of more precise equipment. Even just looking at the image that shows up when you google it will probably give you an "aha" moment, as it did for me a while ago: www.google.ca/search?hl=en&q=Quadrature+amplitude+modulation&btnG=Google+Search&meta=&aq=f&oq=&pws=0&gws_rd=ssl

[@AureliusR]

+Michael Hawthorne To sum it up in one sentence from Wikipedia, which explains why QAM is so amazing: "Arbitrarily high spectral efficiencies can be achieved with QAM by setting a suitable constellation size, limited only by the noise level and linearity of the communications channel."

[@gacherumburu9958]

👍👍

[@rickjljr11]

Why would they use the stiff flanges and closely spaced screws instead of an EMI gasket? The gasket seems much cheaper.

[@KirkOfBellevue]

yes i like this video. finger points to unused mfd button, put multi tone here hint hint.

[@ThoughtMachine1]

SC10 is $350 retail from Stanford Research, fyi.

[@kristhetrader5029]

Mate, great review as always... USB is a piece of crap and I'm VERY glad they have not included USB, instead the same way we do with our equipment, including ethernet is the way to go, more industrial and much more reliable/scalable. Keep them up!!!!

[@Thesignalpath]

+Kris TheTrader Thanks! I find USB to be very useful because it is easy to plug into every PC and laptop. For example, none of my laptops have an Ethernet port on them, but USB is everywhere. I am not suggesting they should have omitted Ethernet, I wish they had included both.

[@shana_dmr]

+Kris TheTrader And pain in the private parts to use when you just want to connect your single device to a single computer that already has Ethernet port used to connect to LAN (as virtually any desktop PC in any company).

[@shana_dmr]

+Kris TheTrader And pain in the private parts to use when you just want to connect your single device to a single computer that already has Ethernet port used to connect to LAN (as virtually any desktop PC in any company).