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How do I configure niRFSA Configure Ref Clock to Ref In correctly

I'm using NI-PXI 5661 RFSA. Derived from RFSA Demo Panel.vi I want to configure my Reference Clock Input to the Ref In Port to sync with standalone equipment.

But the Port is not used after configuring this in the VI's main Case Structure - (Case >Init< ) in a position after niRFSA Initialize using niRFSA Configure Ref Clock.v. 

niRFSA Configure Ref Clock.vi is connected to preceeding VI(Initialize) by Instrument Handle. It is also connected to a ComboBox(Clocksource) created rightclicking clocksource on VI, to a floating constant(clock rate) and error in.

The NI-PXI-5661 is installed in a NI-PXI-1045 Slot 15(5600) and Slot 18(5142). An the NiRFSA driver is 2.1.0.0

(setup.ini, first few lines with GUID and Version#)

[Distribution]
Title=1
GUID={75F16411-DEFB-48D9-AAFF-E5EE242FB467}
PackageGUID={AED9AA8D-0389-4E6A-A611-22E78E80CDD9}
Version=2.1.0.0

 

The internal PLL shoud not lock if the ref input was configured correctly and the external clock source is offline, maybe there should be an error message.

If i tune the external clock source with df=10kHz around (10MHz,13dBm) a reference signal (868MHz, -20dBm) sourced to the 5661 input should move in the spectrum plot, but doesn't.

There are only some spurs in a distance of df at about -55dBm. That says clearly the downconverter runs on its internal Clock and not as desired on the external.

In a previous driver version (unknown version number <2.0.7)  there was an errormessage when just configuring ref in as clock source.

 

Did I forget some preconditions to configure the clock source? Please tell me how to do it correctly.

 

Thanks, Alexander Rolapp

 

 

Message Edited by AlKuRo on 08-22-2008 06:32 AM
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Hi Alexander,

 

Correct me if I am wrong, as I understand it you are manually configuring the reference clock in the "init" case by using the niRFSA Configure Reference clock VI after the niRFSA initialize VI. This is the correct way to set up the reference clock, however I believe your settings are then being undone by the natural progression of the example. The "init" case is followed immediatey by the "config" case when the demo is started up. Inside the "config" case, the reference clock is being set again by the Config RFSA VI. This VI has the reference clock set to onboard by default which will override whatever settings you may have applied in the earlier case.

 

The control for this parameter of the Config RFSA VI in the "config" case can be accessed on the frontpanel when the demo is running by clicking on the Device button in the main menu. My thought is if you set your reference clock there, or adjust it in the "config" case itself, you will see the correct results.

 

Regards,

 

Chris Behnke
Sr. RF Engineer
High Frequency Measurements
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Thank you for your quick reply.

If this was the real cause the solution would be too easy, but its too late in germany to check this now. I'll check it next week.

I thought there was a misconfiguration from previous driver versions where it was not possible to set ref in at all without an error message.

 

...sometimes there are too many cases in a case structure and you just don't get the idea to look for it in another case...

 so thank you very much anyway

 

Alexander

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I double-checked the configuration in the config case today and you're right. Obviously my good old test signal generator i used to tune the ref in signal as mentioned in my first post was to instable at all. The ni-5600 PLL doesn't lock when the ref in signal you provide is more than 20 Hz away from 10MHz. So the tests with tuning the ref in signal had to fail as well.

Now the thing works fine for me.

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Hi Chris.

 

    I have had some problems with the RF_Calibration station when I am performing the VSG-VSA calibration.

    The software shows the message error:

    " Error - 1074130544 occured at niRFSA Configure Ref Clock.vi

    Possible reason(s):

    The session handle is not valid."

 

     The Station was working normally, I don´t know what could be happen.

     Could you help me with this failure?

 

     Thank you so much.

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