External Trigger not working

[mikeh]

I am trying to use my SA44B in zero span mode to capture the amplitude of a pulsed RF signal. I am inserting an external trigger from my target board into the SA44B using a scope probe in x1 pad setting. The trigger has an amplitude of 3.3v is is 2us wide. It occurs every 500 ms. However, using Spike V3.1.7 I am not able to get the trigger to work. The video trigger works fine, but I need to sync to the external signal. Any suggestions as to what may be wrong?

[Andrew]

Hi Mike,

The trigger input port on the SA44B is now solely used for the tracking generator synchronization. There is not external trigger support in zero-span for the SA devices, only for the BB60 and SM200 analyzers. I apologize for the confusion. Ideally we would grey that option out in zero-span mode for the SA devices. As per the product manual, there was triggering functionality in our legacy software, but it was extremely limited and had lots of stability issues.

I apologize for the inconvenience.

Regards,
Andrew

[mikeh]

That’s a shame. I had used this in the past to measure the delay between my logic TX enable signal and the actual RF envelope, which is crucial in pulsed RF systems. I guess I’m very surprised that this important feature has been removed.

I agree that you should grey out the controls in Spike and save lots of people lots of frustration trying to get it to work.

FYI, the spec section of the manual still refers to this capability.

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[Andrew]

Hi Mike,

While not ideal, it is still possible to install the legacy software side by side with Spike to still access this feature when needed. I’ll link the older software version below.

https://relatedcontentdemo.kinsta.cloud/sigdownloads/SA44B/Setup2_18B.msi

Regards,
Andrew

[bittware]

Hi
I confronted the very same frustration.
Without using external trigger, how can we capture the pulsed RF signal, say 3GHz signal with 2uS pulse width?
The pulse repetitive frequency could be 100mS.
Wondering if realtime mode is able to capture such narrow RF pulse?

[Justin Crooks]

bittware,

Real-time or zero span mode will both capture a 2 us pulse. For zero span mode, use video triggering. For real-time mode, you will want to use the maximum resolution bandwidth (RBW) and even still, the amplitude will read low due to the pulse width being less than the RBW time constant.

[bittware]

Hi Justin,
Thanks for the reply.
I tried the zero span with video triggering. It worked very well.
But it seems to have no peak mark tracking capability that realtime mode has.
I also tried realtime mode. It worked as well.
The peak frequencies captured by in these two modes really have good consistency.
Now I’m trying to readout the peak frequency through SCPI command. I read the manual which says the zero span mode is not supported by SCPI yet. So it seems I have to rely on the realtime mode.
As such, could you let me know what SCPI command I should use to get the peak mark frequency read from Spike?
Thank you very much.

[Andrew]

Hello bittware,

You will want to use the :CALC:MARK:MAX and :CALC:MARK:X?; Y? commands to move the marker to the peak and read the position.

You will find examples of usage in the SDK and descriptions of these commands in the SCPI manual which is also in the SDK.

https://relatedcontentdemo.kinsta.cloud/download/bbsa-application-programming-interface-for-windows-3264-bit/

Regards,
Andrew

[Author]

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