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Member
SeanJ
Posts: 155
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e4406a occupied bandwidth

Hi,

 

I'm trying to create a VI to query the E4406a for the Occupied Bandwidth of a  signal.  I've been trying to use the attached VI along with multipledifferent parameters, etc. but everytime it attempts to read the OBW it crashes.

 

It looks like I'm missing something small but whatever it is, it's still a mystery to me.  Any suggestions would be would at this point.

 

Thanks,

Sean

 

 

Member
Nick_Storton
Posts: 160

Re: e4406a occupied bandwidth

Hi Sean,

 

Firstly this board is a discussion forum dedicated to Video and Audio based questions so is not the best place to post this kind of question which is RF instrument based. I have included the link to the RF forum below for your reference:-

 

http://forums.ni.com/ni/board?board.id=290

 

I have, however, had a look at the vi you attached and I think your problem is that the second vi in your program chain is configuring the instrument for a center frequency of 0 Hz (which is DC). I don't believe that this is a valid setting for center frequency as you later try to set the span to 10 MHz, this leads to the instrument trying to configure a measurement between -5 MHz and + 5 MHz (-5 MHz is impossible). The main problem here is that the instrument driver has a default value of 0 Hz for this vi and this is confussing to say the least, it would be better if the driver had a valid frequency setting for it's center frequency. Try setting the center frequency to something above +5 MHz and it should be OK. The other option would be to configure the instrument using the Start / Stop frequency settings.

 

Hope this helps,

 

Nick

Member
SeanJ
Posts: 155
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Re: e4406a occupied bandwidth

Hi Nick,

 

Sorry about that, I'm not sure how this question ended up on the VideoMaster board!  It was meant to go on the main boards.

 

Thanks for taking a look, the current center frequency value is kind of a desparation value.  I had it set at 1GHz and thought I'd see what happened if I used the default. O

 

On a seaparate matter I wonder if there's been any feedback re: limits for VideoMaster and the possible interlacing effect? 

 

Thanks,

Sean

Member
Nick_Storton
Posts: 160
0 Kudos

Re: e4406a occupied bandwidth

Hi Sean,

 

 I've had a bit of a think about this and I've come up with the following vi. I have not been able to test it, I don't have a 4406, but I'm hopeful it should work for you. Let me know how it goes.

 

 

 

Nick