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We have not tested any connectivity other than end to end SFP+ cables (fiber and short copper runs). Most of the customers who have tried converting to RJ45 have had intermittent connectivity issues that were resolved by switching back to fiber. Feel free to experiment if you already have the adapters, but expect it to have issues. We cannot recommend any RJ45 equipment at this time.
Hi Ermy,
The only units we output are the ones in the reference level unit selection, and the only linear unit is mV. I will see if this is something we can easily add in a future release. Thanks for the feedback.
Andrew
Hi Victor,
There is not any way to do this right now, I will see about improving this for the next release.
Hi Testpoint,
Can you provide the following information,
– What company did you purchase this part from?
– When did you make this purchase?Can you please send your replies to support@signalhound.com.
Also, the SM200C phase noise is specified at -76dBc at 10Hz offset.
We look forward to your response.
I do not think there is any warning output with the zero-span recorder. The I/Q recording utility will show the warning (see picture)
Yes that is by design that the utility doesn’t provide an XML, I wanted to move towards a standardized format such as SigMF, but haven’t done so yet. The utility satisfied a number of customers that just wanted long term recording to multiple files and didn’t need the context file at the time.
The utility recorder is optimized for long term recordings and I think will ultimately be better for your use case. It can save to multiple files without gaps between the multiple files. The zero-span recording does not guarantee no-gaps between the files if you choose to output to multiple files (hopefully that’s not your issue). This allows you to load a sequence of files in the VSG60 “streaming” mode and be fully continuous.
I just did some testing here. My SSD claims 550MB/s sustained writes, but using your settings, will only sustain the 400MB/s (required for 100MS/s rate) for ~1 second before dropping to a lower rate of 250MB/s and thus eventually needing to drop data.
I did record the 1 second file at 100MS/s and played back at 50, and everything seemed fine as long as I halved the measurement rate.
Your logic seems sound to me.
2 things that I think could be happening.
1) Is the recording clean? Can you verify there wasn’t some sort of issue with the recording. The main issues being SSD write speeds not keeping up with the data rate, or UDP data loss. Are you using the I/Q recorder in Spike? It should indicate either of these issues. It will appear below the “Rate” label in the I/Q recorder if it occurs. It’s a hidden label by default.
2) Drop outs in the VSG60 output. Are you running the SM200C at the same time as the VSG60? If yes, that could certainly contribute. If you’ve been running other files at 50MS/s without issue, then I would lean towards #1
Is the recording only 2 seconds long? 🙂
If it’s a long file, are you using the “streaming” mode in the VSG60 software? If yes, that means it’s hitting the file all the time. Presumably you aren’t also doing other high speed file I/O while playing back on the VSG?
IBurke,
Thanks for reaching out to us.
It looks like we are helping you via email. For other customers that may see your question, the optimal solution here is to create a simple ARB file with the desired pulse shape, until we add configurable pulse rise/fall times in the software.
Hi John,
No further progress has been made on this, I apologize.
Hi NMullin,
Thanks for the follow up.
I do not believe there is currently a way to play a streaming scenario only once. I will see if this is something that can be easily added.
I should at least mention, that it is possible to use the API to transmit a waveform. The API is an interface for programmatically controlling the instrument without need for the UI application. This would allow you to perform this task relatively easy if you are comfortable writing software. See link below for more information.
https://signalhound.com/software/signal-hound-software-development-kit-sdk/
Val,
Since the Gaussian filter is not a zero-ISI filter, both the filter length and data itself will affect the deviation. You would have to make sure the lengths match, and then do some sort of sync word synchronization to ensure you were measuring the same exact bit sequence in the software. And even then there might be slight differences in the implementation that lead to freq deltas, but I suspect that would eliminate most of the difference.
If you need ultimate control over the symbols and deviation, you could generate your own I/Q waveform and transmit it with the VSG’s.
Otherwise, what you are seeing seems normal.
Thanks Volker, we’ll get that fixed in the next release. Mid-Sept likely.
Unfortunately this is not possible. Spike must run on the PC in which the BB60C is connected. You can use remote desktop like applications to control Spike from a different PC.
One alternative is to look into our SM200C spectrum analyzer. It uses a 10GbE fiber link from PC to device. It would be possible to run a long fiber cable between the PC running Spike and the spectrum analyzer. It would preferably need to be fiber/SFP+ end-to-end.
Val,
I responded to the email you sent that had the same questions.
Just the one demo mode.
We are continuously improving the software. A number of your requested features are already in the pre-compliance measurement mode, such as
– logarithmic freq axis
– Exporting traces
– Exporting trace configurations/settings.Your original request for importing sweeps is not in the precompliance mode. I cannot estimate when you could expect this feature to be released. It is not currently in development. It has been added to our customer request log.
The frame height simply divides the vertical scale by the number of bins. So if you configured it for a 100dB range, then each bin is 100/256 dB in height. If a signal is outside this range, it is usually clamped to the upper or lower bin in a column.
For the width, if it exceeds a certain width we will start binning. For example, 16416 / 513 = 32. So each column will contain 32 frequency bins from each sweep. We accumulate all 32 independently in one column as opposed to creating a much larger image.
Each full frame is roughly 1/30th of a second of sweeps. So you will get ~30 frames per second.
Unfortunately there is no import trace capability in Spike. You would need to export the traces to compare. I apologize for the inconvenience.
We do not specify the accuracy of this measurement. It depends on a number of factors, including the signal itself, and our measurement algorithm. How much accuracy do you need? What are your test requirements? Are you coming from using an instrument where the accuracy is specified? If yes, which one? It may be that we can learn more and attempt to provide you a more concrete answer.
The digital demodulation measurement will automatically measure the deviation. It will measure and report the avg and peak deviation. You just need to configure the symbol rate, Gaussian filter, and 0.5 filter coefficient and it should do the rest. The measurement result is in the EVM summary window.
If you can’t get this to work, email us at support@signalhound.com and we can do additional troubleshooting.
Andrew
Yes this is a known limitation of the VSG25 design. There is no reconstruction filter after the DAC, so you will see DAC images and multiples of the sample rate. For modulated signals like QPSK, the amount of oversampling will determine how far out/close they are.
You can see a picture of this behavior in the production manual, section 6.5.4.
https://signalhound.com/sigdownloads/VSG25/VSG25A%20User%20Manual.pdfAndrew