Siglent SSG5060X-V 9kHz - 6GHz RF Vector Signal Generator Review, Teardown & Exp

[Hugoneus]

You can watch the video here: [56 Minutes]
youtu.be/k_Zpr_CbSRc

In this episode Shahriar presents a detailed review of the Siglent SSG5000X Series RF Vector Signal Generator.

https://www.siglenteu.com/rf-generato...

The SSG5000X series of signal generators can generate analog and vector signals, and have a frequency range of 9 kHz to 4 GHz/6 GHz. They feature good performance in phase noise, spectral purity, bandwidth, EVM, output power. The internal IQ modulation generator and waveform playback function make it easy to create even the most complex signal types. The review is organized at follows:

00:00 - Introductions
00:49 - Instrument front and rear panel features
04:03 - Detailed teardown, analysis and instrument architecture
17:53 - Brief instrument GUI overview
19:32 - Synthesizer phase noise measurements and analysis
22:51 - External power sensor support, power leveling and flatness compensation
30:43 - Pulse generation capabilities and external amplifier characterization
37:54 - Multi-tone generation, limitations and performance
43:47 - Internal ARB, I/Q generation, RF EVM performance and remote GUI access
50:45 - Differential I/Q baseband output performance and configuration
51:50 - External I/Q input support and performance
53:29 - Additional features overview, AWGN, I/Q control, etc.
55:05 - Concluding remarks

www.TheSignalPath.com
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[KE5FX]

The $64,000 question: does it support continuous I/Q streaming from a host PC via USB or Ethernet, with an API or at least a fully-documented protocol?

If not, that'd be a real shame.  It looks like a nice box, but the effort they put into all that fancy firmware is more or less wasted from my perspective.  Just give me a Windows/Linux application with wideband (USB 3 or better) streaming.

This is something the Signal Hound guys got 100% right with the VSG60A.  Their app supports basic modulation and arbitrary-waveform pattern construction... but it also acts like a two-channel 40 MS/s sound card at baseband, which is what's actually needed around here.

[Qw3rtzuiop]

The $64,000 question: does it support continuous I/Q streaming from a host PC via USB or Ethernet, with an API or at least a fully-documented protocol?

I dont think so. Its not mentioned anywhere. Just playback of files that are already transferred to the instrument
Unfortunately live iq streaming to a generator isnt that popular at all. Even the competing entry level VSG Rohde & Schwarz SMCV100B just allows file streaming from a connected hdd.

[KE5FX]

I could live with streaming from an external hard disk, if I had to.  Not ideal.  Hopefully there's a way to convince it to use a shared hard disk of some sort.

What I liked about the Siglent over the VSG60A is that the rest of the hardware looks more like a traditional signal generator.  Case in point would be the output attenuators and (evidently) superior isolation.  For weak-signal work, my VSG60A ends up looking like this:



 

I'm not complaining, because its bang:buck ratio is crazy high.  The SSG5060 looks like a solid full-featured alternative, but only if it can actually do what the VSG60A does.

[tautech]

How large would your IQ file be ?
SSG5000X has 4GB of internal storage and with a webserver to control it with presumably all the features the unit has much will be possible.
Datasheet
https://siglentna.com/wp-content/uploads/dlm_uploads/2020/05/SSG5000X_Datasheet_DS0805X_EN01B.pdf

Haven't yet found anything about streaming in the manual:
https://siglentna.com/wp-content/uploads/dlm_uploads/2021/02/SSG5000X_UserManual_Um0805x_E01B-.pdf

[KE5FX]

How large would your IQ file be ?
SSG5000X has 4GB of internal storage and with a webserver to control it with presumably all the features the unit has much will be possible.
Datasheet
https://siglentna.com/wp-content/uploads/dlm_uploads/2020/05/SSG5000X_Datasheet_DS0805X_EN01B.pdf

Haven't yet found anything about streaming in the manual:
https://siglentna.com/wp-content/uploads/dlm_uploads/2021/02/SSG5000X_UserManual_Um0805x_E01B-.pdf

The baseband rate wasn't very high in the project where I used the VSG60A, typically 3.84 MS/s, but the test recordings were sometimes a few hours in duration.  4 GB would handle most of my requirements, although there were lots of different recordings that needed to be accessed easily, some exceeding 5 GB, that would been a hassle to copy over to the generator each time they were needed. 

There was also a need to alter the center frequency and amplitude during playback, which was easy enough to satisfy with a small custom application for the VSG60A.  In principle that could have been done by sending the appropriate SCPI commands to the SSG5060, as long as it's smart enough to maintain phase continuity, but there were one or two situations where I needed to control the level and/or center frequency of individual bursts.  It would be tricky to accomplish that without streaming.

Another obscure requirement from that project was the need to maintain the best possible phase stability at the nanosecond-per-hour level.  Even though the VSG60A was kept powered up 24/7, the act of sending the baseband data to it was enough to cause some thermal drift due to increased power consumption on the part of the USB chip, the baseband modulator, or a combination of both.  It was helpful to be able to transmit zero-amplitude buffers continuously whenever an actual file wasn't being played back, in order to keep the hardware path active.  That might or might not be an issue with a standalone VSG, but the point is that it was easy to work around since the outgoing data was always under my control.

These issues aren't going to be showstoppers for most people, but that project really taught me what to look for when evaluating an I/Q signal generator.  The ability to stream data from a simple console app on the PC allowed the VSG60A to meet some specialized requirements that the manufacturer couldn't have been expected to cater to.

[Hugoneus]

Thanks for the interesting comments.

To the best of my knowledge, most synthesizers do not maintain phase continuity when the center frequency is changed; maybe at very small offsets some can.

I'll test for this for future reviews too.

[tautech]

How large would your IQ file be ?
SSG5000X has 4GB of internal storage and with a webserver to control it with presumably all the features the unit has much will be possible.
Datasheet
https://siglentna.com/wp-content/uploads/dlm_uploads/2020/05/SSG5000X_Datasheet_DS0805X_EN01B.pdf

Haven't yet found anything about streaming in the manual:
https://siglentna.com/wp-content/uploads/dlm_uploads/2021/02/SSG5000X_UserManual_Um0805x_E01B-.pdf

The baseband rate wasn't very high in the project where I used the VSG60A, typically 3.84 MS/s, but the test recordings were sometimes a few hours in duration.  4 GB would handle most of my requirements, although there were lots of different recordings that needed to be accessed easily, some exceeding 5 GB, that would been a hassle to copy over to the generator each time they were needed. 

There was also a need to alter the center frequency and amplitude during playback, which was easy enough to satisfy with a small custom application for the VSG60A.  In principle that could have been done by sending the appropriate SCPI commands to the SSG5060, as long as it's smart enough to maintain phase continuity, but there were one or two situations where I needed to control the level and/or center frequency of individual bursts.  It would be tricky to accomplish that without streaming.

Another obscure requirement from that project was the need to maintain the best possible phase stability at the nanosecond-per-hour level.  Even though the VSG60A was kept powered up 24/7, the act of sending the baseband data to it was enough to cause some thermal drift due to increased power consumption on the part of the USB chip, the baseband modulator, or a combination of both.  It was helpful to be able to transmit zero-amplitude buffers continuously whenever an actual file wasn't being played back, in order to keep the hardware path active.  That might or might not be an issue with a standalone VSG, but the point is that it was easy to work around since the outgoing data was always under my control.

These issues aren't going to be showstoppers for most people, but that project really taught me what to look for when evaluating an I/Q signal generator.  The ability to stream data from a simple console app on the PC allowed the VSG60A to meet some specialized requirements that the manufacturer couldn't have been expected to cater to.

KE5FX
You have the ear of Siglent....comments about your needs/wishes:
About the feature that alter the center frequency and amplitude during playback, especially in pulse modulation mode. Recently, we are implementing this feature according to a customer's requirement. The description in the EEVblog thread is not very specific. We like to discuss with him about the feature. You could response to ask him to  describe his application more clearly, and could discuss with our engineers.

Further, it seems streaming is under consideration however HW changes are required to support it:
Inside the SSG5000X, there is a 4GB eMMC flash, so it could support long recorded, low-speed continuous IQ steaming. But, current firmware only support 200MSa playback. We will consider to support continually IQ streaming in the future through internal large flash ,USB3.0, 1000 Ethernet. Supporting USB3.0 and 1000 Ethernet, we need upgrading our Zynq processor. That is our next plan.

We can discuss here or by PM.

[colorado.rob]

There have been times I would have liked that feature with my SDG2042X as well. Being able to stream an arbitrary waveform to the SDG would be a great feature addition. Especially if one could stream to both channels simultaneously and guarantee that the samples would be output synchronously.  Even if the sample rate was limited to a few MHz, it would still be quite useful.  It would turn the SDG into a networked 16-bit dual-channel DAC.

[KE5FX]

KE5FX
You have the ear of Siglent....comments about your needs/wishes:
About the feature that alter the center frequency and amplitude during playback, especially in pulse modulation mode. Recently, we are implementing this feature according to a customer's requirement. The description in the EEVblog thread is not very specific. We like to discuss with him about the feature. You could response to ask him to  describe his application more clearly, and could discuss with our engineers.

Further, it seems streaming is under consideration however HW changes are required to support it:
Inside the SSG5000X, there is a 4GB eMMC flash, so it could support long recorded, low-speed continuous IQ steaming. But, current firmware only support 200MSa playback. We will consider to support continually IQ streaming in the future through internal large flash ,USB3.0, 1000 Ethernet. Supporting USB3.0 and 1000 Ethernet, we need upgrading our Zynq processor. That is our next plan.

We can discuss here or by PM.

Good to hear they're listening.   200 MS/s playback would be much faster than anything I've ever needed, personally.  On that project I was working with 3-4 MS/s streams.  They shouldn't feel the need to postpone the streaming feature until they can do it at full USB 3 or 1000BT line rates.

The application for changing the frequency on the fly was Doppler shift simulation.  The workflow involved playing back a captured burst at various frequency offsets, so it could likely have been done on the signal generator itself without too much trouble.  However, I also had a need to insert or remove a single sample from the interval between packets, and that was easier to do in software than it probably would have been in hardware. 

Basically, the message I'd take back to Siglent is that their box should be able to handle the same transmit applications that a USRP, HackRF, ADALM Pluto or similar low-cost SDR can handle.  The SDR vendors don't attempt to write firmware to handle every conceivable vector signal synthesis requirement and data format, but instead leave it up to the user to write the necessary software and stream the baseband data out.  Typically this would be done in MATLAB, GNU Radio, or (as in my case) with a plain old C program.