Search Results for 'api'

[Andrew]

Hi Raja,

The configuration of the receiver plays a big part in the sweep speed. The biggest factors that affect sweep speed on the SA44 is span, rbw, and image/spur rejection. Using Spike, a span of 200k-500k, 1k RBW, and image rejection off, I was able to achieve a sweep speed of around 22ms. I suspect this is about as fast as the API will give you sweeps.

It would be necessary to know your measurement requirements before I could determine whether the SA44 could meet them.

You could increase measurement speed by utilizing the IQ data stream, but this would then require more signal processing (FFTs, etc.).

Regards,
Andrew

So, I have a USB-TG44A and an USB-SA-44B. I’ve had them both for a while and they’ve been working fine.

I recently went to use my TG and I’m getting some strange behavior.

1. Spike 3.1.7 detects the tracking generator and goes into Scalar Network Analysis mode with a “Tracking Generator” box in the upper right, but the displayed chart shows basically no signal – it doesn’t really change when the TG is disconnected from the SA’s input port. The BNC cable is connected between the two.
2. The Spike 3.1.7 Standalone Tracking Generator app hangs at “Detecting devices…
3. The Spike 2.18B Standalone Tracking Generator app loads but hangs at “Downloading Calibration” when I click “Apply”.
4. The Linux TG API 1.1.0 works fine; I’m able to set frequency and amplitude (verified with an oscilloscope).

I’m running Windows 10.0.14393 Build 14393 on an HP Laptop that dual-boots Windows 10 and Fedora 25 Linux. The USB Serial Port for my TG is using FTDI driver 2.12.24.0 per Windows Device Manager.

I’ve rebooted and unplugged-reconnected every which way.

What can I try next?

[Andrew]

Hi Charles,

Thanks for the feedback. The software you describe is what we would eventually like to offer. As previously mentioned, we don’t have any definite plans or time frame for this yet. I would not expect this type of functionality soon. We did just simplify the interface between LabVIEW and our programming APIs recently. I would think the easiest way to get to OFDM demodulation would be to use third party software (Matlab or LabVIEW) with our programming interface. Having never done this, I can’t say what kind of effort this would require.

Regards,
Andrew

[Andrew]

Hello Raja,

You can find the peak amplitude by searching for the largest value in the sweepMax array that is returned from the API.

Regards,
Andrew

[Andrew]

Hello Raja,

Here is the code for finding the peak frequency in C.

In the code below, you will already have sweepSize, binSize, and startFreq from the API, and you will have the sweepMaxArray from the get sweep API function. This should be easy to convert to Visual Basic.

double peak = -2000.0; // Small initial value
int peakIndex = -1;
for(int i = 0; i < sweepSize; i++) { if(sweepMaxArray[i] > peak) {
peak = sweepMaxArray[i];
peakIndex = i;
}
}

double peakFrequency = startFreq + binSize * peakIndex;
double peakAmp = peak;

Regards

[raja62]

Hi,
Would any one have tried using the SA_API in Visual Basic 2010.
I managed to get most of the functions working.
Now I am trying to get Peak Frequency.
But there is no specific function.
Any assistance is much appreciated.

Thank you

[catalin_ro]

Hello Mikes,

I’m probably one of the guys that Andrew mentioned by “several customers”! I’ve just seen your question, so sorry for the delay in my reply!

Briefly said, we currently have a platform involving 2 BB60Cs and a simple (FTDI serial port basically!) device that we operate through a 10m USB3 active cable and a 4-port USB3 hub and we saw no major issues. But in order to get to the current structure, that can be connected to several PCs and shows no significant performance differences, we ended up with a box of useless USB3 hubs!

With two BB60Cs there is a rather small performance regression with latest APIs. At some point in the past it was terrible but Andrew sorted it out! And for 7 BB60Cs you need to consider a pretty powerful CPU.

I will do some tests with even more BB60Cs connected at once to the same PC as I am involved in a project where I need 14 units. Clearly I won’t go that far, as the project doesn’t require them in just one place, but I will certainly do some tests with as many as possible connected to the same PC.

Just as a warning, depending on the motherboard chipset and/or USB hub, you might see periodic errors while streaming, with the end result of missing samples. With similar structures I testes on several platforms and so far I could not find a general rule. But, on the platform where I see it happening, it tends to happen also when only a single BB60C is connected directly to the PC.

Anyway, our “nightmare” is that we need those two BB60Cs to be in sync!

Regards,
Catalin

I have a BB60C. I found the Spike this software can import .csv file to set Limit-Line. But I can not found LabView vision API this function.
Anybody know how to used LabView to set Limit-Line.

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Dear all,

Recently, I wrote a C app on my 64 bit Linux PC (Ubuntu 16.04 LTS) , through the Linux API provided in the following page, it performs well.

https://signalhound.com/support/product-downloads/sa44b-sa124b-downloads/

However, when I port the same C source code to the Raspberry Pi 3 Model B (with Raspbian OS and g++ 4.9.2), the ARMv7 API provided in the same page cannot get the job done.

To identify this issue, I tried the example “sweep_and_iq_test” along side with the ARMv7 API, it seems like the same error is inevitable.

The output message from example code “sweep_and_iq_test” is following:

saOpenDevice No error
saConfigAcquisition No error
saConfigCenterSpan No error
saConfigLevel No error
saConfigSweepCoupling No error
saInitiate No error
pure virtual method called
terminate called without an active exception
Got Sweep 0
Got Sweep 0

Clearly, this happened when the function saGetSweep_32f(device, min, max) is called.

I think the issue: “pure virtual method called / terminate called without an active exception” can be identified as the thread join/detach problem.

Could you provide me any suggestion or support for this issue? Thanks a lot.

[Andrew]

Hello Yu Ching,

You are correct, there is no direct channel power measurement in the API. You will need to calculate it. The most typical way this is performed is by either integrating the frequency bins of a sweep (in power units) or averaging the power of an IQ waveform. LabVIEW might have these measurements available in the signal processing or related libraries.

I will attach the pseudo-code for the sweep method. This is pulled from Spike.

Let me know if you have further questions.

Regards,
Andrew

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I have a BB60C. I found the Spike this software can test channel power. But I can not found LabView vision API this function(channel power.).I alway ready use the API catch the signal by LabView
Anybody know how to used LabView to analyze (Channel power)?

I have recently gotten the following error when loading a program that uses the SA_API:
This application was unable to start correctly, (0xc000007b).
I don’t get this error on other computers. Spike works correctly on the same computer. One difference is that this computer runs Windows 10. Any thoughts?

Hello.

We are trying to use the TG44A with a small form computer. I was wondering if the API and drivers are compatible in any way with the Raspberry PI 3 boards or with the Intel NUC mini computers.

Thank you for your help.
Gabi Constantin.

[Andrew]

Hi Jared,

You are correct. These measurements are features of Spike and are not available through a public API.

The SA44 API consists only of low level data acquisition functions. You would need to use the API to retrieve IQ data from the receiver and then make your measurements on this data. Average power would be easy to calculate but carrier offset of a digitally modulated signal is non-trivial.

At this moment, there is not a way to retrieve these measurements programatically. We have talked about making Spike programmable via SCPI but there is no definite plans of this yet.

I apologize for the inconvenience.
If you have additional questions, please let me know.

Regards,
Andrew

I am currently developing a test fixture for calibration/testing of an RF module. Each module needs to know its RF power and carrier offset. My USB-SA44B can report these numbers when configured in modulation analysis mode. However, I don’t see any references to modulation analysis mode in the API. Does this mean that modulation analysis mode is a feature of Spike, and not the instrument per se?

[Andrew]

Hello g0s,

There are a few ways to load a custom waveform for the VSG. I know you don’t want to use the application we provide, but the easiest way is to use the UI to load the custom waveform file. There are example waveform files in the application directory at
C:\Program Files (x86)\Signal Hound\VSG25\arb_examples
You can also use the C programming interface we provide, the files for which are also provided in the application directory at
C:\Program Files (x86)\Signal Hound\VSG25\api
You will want to use the sgSetFrequencyAmplitude and sgSetCustomIQ functions to achieve this.

Waveforms can be created in excel or a number of other ways, common ways might be using a math library such as Matlab, etc.

Let us know if you have more specific questions.

Regards,
Andrew

[Justin Crooks]

The .csv file is generally for non-standard waveforms. Our API can be used to control the VSG without the GUI.
The CSV file can be used if you have less than 2048 I/Q samples you wish to send, either as a repeating burst, or a continuous loop.

[Andrew]

Hi Jason,

We currently don’t have an ARM build for the BB60C. It is unlikely we will any time soon, because we would have to find replacements for the signal processing libraries we use, which target x86/x64 specifically. The processing requirements are simply too high to re-implement the functionality in naive C code and have it run on ARM.

Although, we do have a BB60 Linux build for x64 and it does not require any modifications to the kernel to run. A standard Ubuntu (or similar) install will work fine. We used the libusb library for USB 3.0 with no issues.

It should be stated that our Windows APIs are the only APIs that receive full support. We do fix issues in our other APIs but it may take awhile compared to the Windows versions.

Regards,
Andrew

[joeqsmith]

What version of Labview are you using?

Do you have a specific question? You may want to upload your code that you are having problems with.

If you are just looking for a general idea how to do it, the SA example is where I started. API manual is good enough. I really have not seen too many problems that were not related to lack of sleep.

[Andrew]

Hello Mehran,

I apologize that you are having issues.
Lets wait another week or two and we will release some .vi’s and examples that should help you get going. This will be part of our API download SDK once released. Check back in a couple weeks.

In the meantime, someone on the forums may be willing to help you out with your Labview issues. The only tips I can provide is to look at our existing SA API example for Labview. Also check out the BB60 API C examples which show how to use the API.

Regards,
Andrew