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DDR,
In general, our VSG’s are not an alternative to an 80MHz ARB/function generator.
That being said, if you have specific signal generation requirements, we could help you determine if the VSG25/60 would be suited for any part of your application.
Regards
Hi Bill,
Very fascinating behavior. From the measurements point of view, nothing changes with the dialog active. Sweeps are still polled at the same speed, etc. The dialog being active could trigger other system behavior, maybe the system is giving increased CPU resources to our application with the dialog entry open, or something like that.
If you change the start freq from 10Hz to 100Hz or even 1kHz, does the USB error go away? The 10Hz start frequency requires a large continuous acquisition, and if your system was barely meeting USB throughput, that might push it over the edge.
Things that can affect USB throughput,
– Ensure your PC is set to “High Performance” power options. See the picture on my reply in this forum post. https://signalhound.com/support/forums/topic/vsg60a-stability-in-cw-mode-versus-multitone/
– Disable any anti-virus temporarily.
– If the BB60C is connected through a USB 3.0 hub, try removing the hub as a test.
– It sounds like your test setup is using another USB device. If that device is also a high USB usage device, that could be contributing to this.
– Keep your laptop on wall power.In general I would not expect the auxillary power cable not being plugged in to result in data loss, but its possible. Does plugging it in resolve the issue? There is a separate low voltage warning you would see, and you might see sagging measurement values if power was an issue.
I look forward to your response.
-AndrewBill,
Your first screen shot (630) shows an uncal USB warning, which would indicate data loss over USB during the measurement. This would generally affect the measurement negatively as there would be discontinuities in the acquisition, increasing the phase noise. The fact that you had a good measurement (no USB warning) with the dialog open is interesting, but might be a coincidence. USB data loss is generally random. In theory, nothing is different about the measurement when the dialog is open.
This USB warning will appear in most measurement modes. Can you confirm that you are seeing this reliably in either sweep or phase noise mode? If yes, we will want to troubleshoot this. If yes, can you provide the make/model/CPU of your PC?
You can reply here, or directly to me at aj@signalhound.com. I can send you some troubleshooting steps to try to help this.
I look forward to your response.
Regards,
Andrew April 6, 2021 at 12:53 pm in reply to: Spectrogram Frequency Limits Do Not Change on Recorded Spectra Thanks Gary. I appreciate the feedback as always. I agree this would be a useful feature. I’ll look into what improvements we can make on this for future releases.
Regards
Volker,
Thanks for your feedback. I have made a note of this for the next time we revisit the Noise figure measurement.
Regards,
Would having the ability to disable the software IF filter be of interest? That would resolve the issue you mentioned in the other thread, the AM plot would line up with the trigger position. The hardware filter rolloff is a bit rough without this filter, and there is some foldover/aliasing at the band edges, I don’t know if that would affect your measurements.
There isn’t a way to control the FMT size independent of the display RBW size right now. The idea was to ensure the customer could visualize the noise floor at the given FFT size. That being said, I could see the need to uncouple them. I will make a note of this, I don’t think it would be difficult to add in a future release.
Regards
jjoonathan,
You can change the FFT size used with FMT triggering by adjusting the RBW. If you change the RBW to 1MHz for example, a 1024pt FFT will be used (round up to the next power of 2).
You might need to adjust your FMT after you increase the RBW since the noise floor will increase.
The min/max FFT sizes that are actually used on the hardware are [512/16384]. Anything below or above those values will be clamped.
Hopefully this help improve the jitter enough to be usable.
You might already be aware, the API is available, and the 250MS/s I/Q captures are can be programmatically controlled through the “Segmented I/Q captures” API. We have several examples of this in the SDK. For your chirped signal, you could setup the video trigger level as you are in Spike, collect the data, and realign the trigger post acquisition. (basically run another video trigger in software). Justin mentions the video trigger limitations in your other thread.
We appreciate your feedback and detailed posts. It’s great to see the wideband captures being pushed to their limits!
https://signalhound.com/software/signal-hound-software-development-kit-sdk/
Jason,
I rolled back the version until we can get a fix. Continue using 3.5.14 for now.
Apologies
Arthur,
I can look into updating this for a future version of Spike. Another customer has commented on something similar in the forum. I’ll see about adding it.
Thanks for the feedback!
Regards,
Andrew March 15, 2021 at 11:10 am in reply to: Feature Request – Adding text to display window in the sweep mode Hi m.wenglar,
Currently the only option we have available for this is the title. In the edit file menu you can change a one line title. Is this enough room for your notes? If not, then you would have to export a picture and use paint or some other similar program to add text. I do have this feature request from another user, I’ll add your name to it. It’s interesting and something we can consider adding to a future version of Spike. I can’t make any guarantees on when.
As an alternative, if you are using Windows, you can use the snip n sketch tool to take a screen shot then from within that app open the screen shot in paint to add your text. There are also 3rd party windows applications that have this functionality (annotate a screenshot) all in one. I personally haven’t used any of them.
Regards,
AndrewThanks for the feature requests Jan. I appreciate the detailed feedback. I enumerated all of your requests in our request log, I can’t make any guarantees as to when we would be able to implement these.
Regards,
AndrewHi Jan,
We do not have integrated support for this. We don’t have hardware/firmware level support on the VSGs for the sync trigger. You could manually sweep the VSG and SA to effectively use it for scalar network analysis but it will be much slower.
Regards
Jan,
The automated meter measurements are being actively worked on. Look for this in the next release of Spike.
I’ve added your copy screen request to our request log.
Regards
Volker,
Thanks for bringing this to our attention. This appears to be a bug. We can get this fixed and in the next release of Spike which should be in the next couple weeks.
Thanks again!
AndrewGlad to hear that you love your new SM200B. That’s great!
Regarding preselectors, check out section 3.3 of the product manual linked below for the full description.
https://signalhound.com/sigdownloads/SM200A/SM200-User-Manual.pdf
Above 645MHz, the preselector filters are always on, since we have enough filter overlap to measure at any of those frequencies with any IF bandwidth. The narrower filters below 645MHz are the ones that are controlled with the preselector control. For sweeps, enabling the preselector will slow down the sweep for the benefit of the extra filtering. For I/Q streaming and real-time measurement applications, enabling the preselector means we can only enable a single filter. In these situations, you can refer to the filter list in the above manual to see which filter is used at specific frequencies.
I hope this helps. Let us know if you have further questions.
Andrew
jpetrik,
Thank you for the feedback. I agree this would be a useful feature. Would a button that automatically performs the QP measurement on all current peaks in the peak table satisfy your workflow requirements?
Regards
Hi fgroger,
Unfortunately the VSG25 and VSG60 do not share drivers or codebases. This request is something I could add to our customer request log, but I don’t have any sort of timeline on when I could try to port the VSG25 to Linux. We have not done any work to ensure all drivers are available or that code could be easily ported to Linux. It was designed as a Windows only device.
As far as the SA44B on Linux, we are glad the Linux APIs are satisfactory for you. Just note, we have obsoleted our Linux APIs for the SA44B due to limitations between the drivers and how we handle USB transfers. We noted periodic data loss that cannot be avoided, detected in software, or recovered from in our current design. Something to keep a look out for moving forward.
Regards
Hi Gary,
The sweep time under the spectrum is a measured sweep time. The resolution on the timer is coarse and provides a rough estimate. This sweep time includes acquisition and processing time. The sweep time control is used to specify a minimum acquisition time. We attempt to acquire data for at least as long as the value provided here. There are situations where we may not be able to accommodate this, and there are other situations where we may have to overshoot this value by a bit. Either way, we try to get as close as the hardware will allow.
Regarding acquisition lengths… The BB60C measures spectrum 20MHz at a time and stitches the results together to form the final sweep. At each 20MHz step we might acquire more data than is truly necessary, either due to minimum acquisition lengths of the hardware, increased sweep times set by the user, or even the default 1ms sweep time combined with a narrow span and large RBW, which results in acquiring more time data than is necessary to achieve the selected RBW. We process this time data with overlapping FFTs and use the detection algorithm selected (minmax/avg) to produce the final result. The BB60C always performs as many overlapping FFTs as possible with its acquired data, unless the “sample” video units are selected, at which point, a single FFT is performed, and no minmax/averaging is performed.
I hope this helps.
Regards
Terry,
Thanks for the information.
If you still wanted to try to use the SYST:IMAG:SAV function, there is a common issue that might be tripping you up. For file names over SCPI, standard convention is to include quotes around the file name. So in manuals the command looks like this
SYST:IMAG:SAV “C:\Users\AJ\Documents\SignalHound\images\scpi.png”
In your code though, you will need to be sure to put escape characters before the quotes so they are actually part of the string. So it might look something like this. In C++,
std::string msg = “SYST:IMAG:SAV \”C:\Users\AJ\Documents\SignalHound\images\scpi.png\””;
I find this annoying as it has tripped up many of our customers now, but it makes it really easy to parse filename that include spaces, so I imagine that is why people standardized on this.
I can definitely look into retrieving the temp/voltage through SCPI. This would be a very quick and easy add for us. Look for this in the next release.
Regards
mcline,
In general we have found that most USB 3.0 ports will provide enough current to run the BB60C and VSG60 off of a single USB 3.0 connection. Where the second cable/connection is usually needed is on ultraportable laptops, ones that are optimized for low power consumption like the MS Surface Pro. I have not seen a port become damaged, but on those low power laptops, sometimes what you will see is Windows will shut off that port if it detects high current draw. It’s restored on a PC restart. If you have a machine that exhibits that, usually a powered hub is the best workaround.
When both connections of the y-cable are used, we don’t generally see any issues.
I would recommend the following 3 USB hubs, we know they work with our receivers and have been used to connect multiple devices simultaneously.
https://www.amazon.com/dp/B014ZQ07NE/ref=emc_b_5_i
Let me know if you have follow up questions.