FM modulation

[afatbahmed]

i have an NI PXIe-1062Q chassis with an NI PXIe-8130 embedded controller.

in the slots i have an RFSG 5672 comprising of the 5610 upconverter and the 5442 AWG.

i also have the RFSA 5661 comprising the 5600 downconverter and the 5142 IF digitizer.

now i am trying to run the example code RFSG GENERATE FM.vi.

i want to fm modulate. in the code there's a property node that has the properties I/Q rate(S/s), waveform quantum and signal bandwidth of some others.

i am stuck at this part because i don't know what the I/Q rate and the waveform quantum is?

the Vi however ultimately returns the FM envelope of the carrier as well as that of the baseband signal.

i hope i have presented my problem clearly and consicely. i'd be very appreciative if someone helped me on this.

[Jordan F]

Hi,

Thanks for posting to the NI forums.  I am unsure as to what you mean when you say, "you dont know what the waveform quantum or I/Q rate is."  If you want to find the specific value you can place indicators or probes on the block diagram after the property node to see the exact value depending on your configuration settings.  If you are just unsure what these terms mean than this may help:

IQ rate: The IQ rate and bandwidth are directly proportional (Acquired bandwidth = 0.8*IQ rate).  The help states that "Given a desired signal with the maximum frequency content f, sample the signal at an IQ rate greater than or equal to (f/0.4).

Waveform Quantum: This returns the quantum value that the signal generator supports with the current configuration settings.  The number of samples in the waveform generated must be an integer multiple of the this value.  The value of this property is determined by the IQ rate so that is why it needs to be set in the configuration before you can return this value.

I hope this helps answer your questions.  If you have any questions on specific properties or what is supported for the 5672 or 5661 a great reference is the NI RF Signal Generators Help and the NI RF Vector Signal Analyzer help.  These can be found in the Start Menu>>Programs>>National Instruments>>NI-RFSA or NI-RFSG.

[afatbahmed]

Thank you Jordan.

 I'll follow up on the information you gave. thanks again. 

[Siew Hong]

Hi, I have previously did some recordings via the 5600 downconverter.

I would like to upconvert my recorded files via the 5442 AWG and 5610 upconverter. 

Would appreciate very much if someone can shed a light on this issue.

Thanks and Regards,

Judy Tan

[chris_amadasun]

Hi Judy,

We have a couple of examples that can help you, deoending on how you have stored your waveform you can use the examples listed below.

Navigate to your LabVIEW folder (for LabVIEW 2009 thats)

C:\Program Files\National Instruments\LabVIEW 2009\examples\instr\niRFSG

You can open and look through the following examples

RFSG Arbitrary Waveform Streaming.vi

RFSG Arbitrary Waveform Generation.vi

From these examples you can architect your code.

[Siew Hong]

Hi, Chris.

Thanks a lot for your help.  I did found a similar RFSA Arbitrary Waveform Streaming.vi which resides within Labview 8.6.

You have mentioned that I can use this examples to architect my code.

Are you referring that I need to make some modifications to the code to suit to my recording format (ie. header within the binary file)

Thanks and Regards,

Judy Tan 

[chris_amadasun]

Hi Judy,

Yes you will have to modify the code to suit your recording format.

How is your data saved? 

[Siew Hong]

Hi, Chris.

I have no problem running the default chirp binary file using the RFSA Arbitrary Waveform Streaming.vi

However, I encountered "output" problem when I used my recorded binary file.

My recording format is in IQ (12.5M S/s)

How should I go about it?

Thanks and Regards,

Judy.

Message Edited by Siew Hong on 05-20-2010 02:21 AM

[chris_amadasun]

Hi Judy,

Can you give me the exact error that you are seeing, a LabVIEW screenshot along with some code would really help me debug this issue

[Siew Hong]

Hi, Chris.

I have captured a LabVIEW screenshoot of the exact error. Beside that, I have also included the RFSA Arbitrary Waveform Streaming.vi code within the zip file.  The code itself is orginated from the LabVIEW 8.6 program folder.

Hope to hear from you soon.

Appreciated that you have me so much along the way.

Thanks and Regards,

Judy Tan