5142 channels

[madd]

Hello

My question is how to digitize Data using channel 0 and channel 1 of a digitizer simultanously. i have made two VI files for this running on 5142 channel 1 and channel 2 using two different anttenas but  when i run one the other is stopped . or when i try 2 run both simultanoiusly error comes which says No proper handle found and the "niscope close.vi" blinks and one VI is stopped.

Regards

Madd

[abhisheknag]

Hello Madd,

I modified a shipping NI-Scope example to write the attached basic example that demonstrates multichannel acquisition using NI-Scope. I have left the example very sparse on purpose to illustrate the "active channel" concept. There are two things you need to do differently:

1. Specify the active channels you want to acquire from.

2. Use one of the "multi waveform" polymorphic instances.

Please let me know if this helps.

Regards,

Abhishek

[madd]

Hello

Let me make my question more detailed. As we Know that channel 0 of 5142 is an OSP enabled/disabled channel.and channel 1 is a straight channel I want to perform real acquisition using channel 0(with OSP enabled) and a complex/real acquisition using channel 1 at the same time in the same Vi or in two different VI's running in parallel . R u getting my point. Also is it possible that I acquire one signal using channel 1 from RFSA configuration and other channel 0 from an external downconverter simultaneously.

Regards

Madd

[HSD]

The 5142 can't do a complex acquisition on channel 0 and a real acquisition on channel 1 at the same time.  For that functionality you would have to synchronize with a second digitizer.

[madd]

Hello

u forgot to provide justification. Ok lets look at thin in this way . i want to acquire both complex signals using both channels simultaniously

now how to do (keeping in mind the  Questions above )

Regards

Madd

[Speedy_Badger · Accepted solution]

Hi Madd,

The justification is in the block diagram of the 5142, and more specifically the block diagram of the OSP.

Notice that in the 5142, both CH0 and CH1 are routed to the Decimation or OSP block. See image below:

Now notice that in the OSP itself, both channel 0 and 1 are being used in the DDC for downconversion. See image below:

As you can see, both channels are being used for the OSP functionality even though the source of the data came from one ADC channel. To do this we essentially route the same information from ADC0 to both CH0 and CH1 and perform the OSP operation.

If you would like to use CH0 and CH1 independently, you will limit yourself to decimation only - Digital Downconversion and complex baseband will not be possible.

Regards,

Message Edited by Speedy Badger on 03-04-2009 11:37 AM

[HSD]

Technically you can do downconversion from ch 0 and ch 1 at the same time.  However, you will only get real data (and not complex data) for each channel (I is ch 0 and Q is channel 1).  Also, both channels will have to frequency translate from the same IF/center frequency.  If you want to do this, then start from the baseband example and enable frequency translation (and set the center frequency).  You will probably want to set the I and Q phase appropriately.

[Chris_W.]

Hello Madd,

Because your question on this post is the same as on other threads, we would like to consolidate your posts to one thread so that everyone who is interested can follow the progress of your issue. All further activity on this issue will continue on thread linked HERE. Thanks.

Chris W

[Chris_W.]

Hello Madd,

Because your question on this post is the same as on other threads, we would like to consolidate your posts to one thread so that everyone who is interested can follow the progress of your issue. All further activity on this issue will continue on thread linked HERE. Thanks.

Chris W