Thanks for the update! Glad that fixed it. Let us know if you run into any other issues.

Cheers

[Andrew]

Michael,

Are you using the latest version of Spike? (3.5.16) The latest version included a bug fix that was supposed to address this.

http://www.signalhound.com/Spike

Regards

• This reply was modified 3 years, 11 months ago by Andrew.

Hi John,

Broadcast masks were introduced into Spike under the Spectrum emission mask measurements awhile back (analysis mode drop down menu). For the SA44B, you may need to disable the outermost ranges (the ones that are > -80dB down) as the SA44B doesn’t have the dynamic range to measure these ranges. The noise floor will trip it. That being said you will still be able to visualize the ranges.

If you have any questions as you start working with this measurement, please let us know.

Regards,
Andrew

The VSG60 does have SCPI support. It is through the VSG60 application. You would launch the app on the remote PC, then you would be able to use SCPI to control the app (socket interface, default port 5024). The app does have a generic ARB mode, it will load several types of custom I/Q waveform files such as binary, CSV, wav, and some others. The ARB mode can be fully controlled via SCPI, including loading files. With this approach, your waveforms would have to be stored in a file.

The API will only communicate with a locally connected device. To use this in the same fashion, you would have to build some sort of local application that controls the unit and awaits commands from your remote script. This might ultimately provide more flexibility at the cost of more upfront work.

You can find the VSG60 SCPI manual in our SDK, linked below.
https://signalhound.com/software/signal-hound-software-development-kit-sdk/

If you have additional questions let me know.

Andrew

[Andrew]

It just looks like your scaling/conversion if off.

The Spike user manual documents the equations used to convert the file contents to scaled I/Q values, if you haven’t seen this already.

Have you stepped through your code and verified scale factor is correct?

Have you tried verifying your conversion works for fixed values? You could force 1+0i (SHRT_MAX,0) and fixed scalings to verify the conversion works properly.

That should fix the AMvTime plot. Our I/Q plot is in mV, so there would need to be another conversion if you wanted those units. Right now you are simply plotting I/Q straight from the device it appears.

I’m not sure whats happening with the FM. Maybe really small values create this? zero values? It doesn’t look like a phase discontinuity. Maybe phase wrapping like Justin said?

Regards

• This reply was modified 4 years ago by Andrew.

Cyprien,

If you use the time overview plot, you can drag the left/right vertical black bars to zoom in on a particular section of the plot. When you do this all other plots will update to only show this region of the capture. The AM vs time plot Avg power will update to reflect the avg power of just this region of the capture.

Regards,
Andrew

[Andrew]

Hi Cyprien,

Thank you for your feedback.

I agree, more functionality could definitely be added to the I/Q playback. You are running into some of the limitations of the feature. I can acknowledge some of your points.

– There is no controls or keys for scrubbing through the file, such as step forward/back/etc, other than the single step button for advancing 1 step.
– There is not currently a way to go to an exact time.
– The rectangle viewport has a minimum size so it can always be grabbed easily. This might be deceiving for very large captures.
– The resolution on the rectangle position is 1 pixel. With your file at 8GB in size, 1 pixel might be a lot of samples. Finding a signal this way will be difficult.

It was originally designed for shorter captures, and the controls reflect that. I have added some of your ideas to my notes. When we are able to revisit this portion of the software I think we should be able to add much of this.

One suggestion I might have, is to increase your sweep time to the maximum allowed, which will clamp at 4M points. This will effectively make your rectangular view into the file as large as it can be. Then you more easily use the per view zoom/scroll when you have found a signal of interest. This may not work for all use cases.

Additionally, signals can also be video triggered in the file. If your signals of interest have clear RF level rises, use the video trigger to find your signals. This might introduce some lag at large file sizes.

I should also mention, there exists third party software solutions that have extensive capabilities in this domain. See our third party vendors at this link. https://signalhound.com/support/third-party-software/ In particular, offerings from 3dB labs and Procitec have the types of features you are looking for.

I appreciate you taking the time to provide this feedback.

Regards,
Andrew

• This reply was modified 4 years ago by Andrew.

Volker,

Thanks for the feedback!

This did come up in discussion when developing the feature. Those noise sources need a 28V supply which none of our devices can provide. We would have to rev the hardware for this.

An alternative is to use the trig port to drive something external that powered the noise source. Is this what you had in mind?

I look forward to your response.

Andrew

[Andrew]

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

• This reply was modified 4 years ago by Andrew.
• This reply was modified 4 years ago by Andrew.

[Andrew]

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.
-Andrew

• This reply was modified 4 years ago by Andrew.

[Andrew]

Bill,

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

• This reply was modified 4 years ago by Andrew.
• This reply was modified 4 years ago by Andrew.

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,

[Andrew]

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

• This reply was modified 4 years, 2 months ago by Andrew.

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

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,
Andrew

Thanks 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,
Andrew

[Andrew]

Hi 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

• This reply was modified 4 years, 2 months ago by Andrew.

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