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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.
Hi twood,
Thank you for the feedback.
We are looking into the font size issue. It looks like the font size is scaling in ways we didn’t intend. In general, yes we are going for a font size that matches the other text. Looking into that now, once we have a fix, we can get that into the next release of Spike.
The other meta data is something that has been requested often. Hopefully if we can address the font size, the presence of the meta data will have less of an impact on your usable screen real-estate.
I have entered feature requests for your resolution selection and the ability to enable/disable the new on image text. How are you taking images right now? Via SCPI? Or are you logging into the system remotely?
You can download older versions of Spike using this direct link.
signalhound.com/sigdownloads/Spike/Spike(x64)_3_5_12.zip
You can modify the version number. 3.5.12 was the previous version if you wish to go back to this in the meantime. I have mentioned this to our IT dept and potentially we can get an version archive available to users.Thanks again for your feedback.
Regards
gkang,
If I’m understanding your problem correctly, something like the external trigger could help with your problem. If your generator can emit a trigger at the same time as the RF, you can stream I/Q data on one of our receivers and measure the time from the external trigger position to when the RF energy arrives. You can do this with both the BB60C and SM200 using the SDK. We also have external triggering in the Spike application for these two devices, so depending on how complex your setup it, you might be able to do it with Spike.
Let me know if you have follow up comments.
Regards
tyang,
1) This will be difficult to measure. This number will include USB transfers, hardware acquisition speed, as well as buffering and processing latencies in the API. For certain modes like real-time, we only provide sweeps at specific intervals which means the latency for a specific event can be anything up to that interval. That being said, latencies are likely in the 16-100ms range depending on the measurement.
2) In your code I do not see a channel power measurement. Each call to saGetRealTimeFrame returns one sweep and one persistence frame (to create the persistence display). For your purposes you can ignore the frame and just focus on the sweep. You are indexing just a single value in the sweep. The channel power measurement in Spike is an integration over a portion of the sweep based on your settings. There will be additional math to calculate a channel power value on a sweep returned from the API.
We have a couple of resources that can help you get started. The equations for calculating it are in the blog post. I have also attached a file that contains some code snippets from Spike that calculate channel power. You will not be able to compile this code, but it will illustrate the operations involved and you should be able to write your own implementation using it.
https://signalhound.com/news/what-is-channel-power-and-occupied-bandwidth/
Regards,
AndrewHi ghuxtable,
Yes, changes in the reference level affect sensitivity, which change gain and attenuation of the instrument. A lower reference level implies you will be making measurements on smaller signals, in which we increase the sensitivity.
In standard sweep mode, linear scale frequency is the only scale possible. There is no way to plot on a logarithmic scale outside of the precompliance mode. I apologize for the inconvenience.
Regards
ghuxtable,
You can convert to dBm from dBuV by simply subtracting 107dB.
Try decreasing your reference level. The devices maximum sensitivity is ~50dBm or 57dBuV. Your noise floor will drop ~30dB from its current position. This will get you very close to the pictures in the other software you provided. Decrease ref level to 60dBuV or 55dBuV. Any lower than -50dBm and you won’t see any improvement in the noise floor.
Your path loss table values appear correct. Our software will linearly interpolate between your points. If you need more resolution you can also add more points later.
Regards
Thanks for the follow up information Volker.
Did you see the Spike manual section on Noise Figure? We have the equations we use for the measurement. We will be writing a white paper for this soon.
I agree that measuring the noise source once is the best first step for automation.
NF of the BB60C will vary slightly per device, but is roughly the DANL of the instrument + 174. You can find the DANL specs in the product manual.