usrp waveform

[Aomine]

i am just new with transmitting and receiving from USRP so i am haiving two questions

1- when i send the samples of my signal on the USRP i can conrtol the difference between samples which is to make it 1 microsecond but the RECEIVED signal between samples it's 1 milisecond which is very large for my project so how can i control the scale of the received signal to be less than 1 milisecond

2- how can i make the time of the received singal to be a real time ? 

Thanks in ADVANCE

[4Matted]

Could you please post your code here so I can see how you are reading your data in? When you say you want your data in real time do you mean when it is displayed in a chart or are you referring to time stamping your data? Thanks for your help. 

[Aomine]

Yes I mean to display on chart on real time and here you are the code i am transmitting and receiving using the USRP i think its very basic code so i apperciate your help 


Thanks a lot 

[Aomine]

Yes I mean to display on chart on real time and here you are the code i am transmitting and receiving using the USRP i think its very basic code so i apperciate your help 


Thanks a lot 

[4Matted]

When I ran this example here I recieved an error on the transmit side of your code. My recommendation would be to open up the "niUSRP EX Tx Continuous Async" and the "niUSRP EX Rx Continuous Async" example and run them both and see if you are seeing the behavior you expect when using the examples. 

To answer your second question, You can see the waveform time stamps by right clicking on the graph going to the graph properties, selecting scales, and unselecting "Ignore waveform time stamps on x-axes". This will out the time correlated to the measurement on your graph. 

[giube]

Hi all,

thank you for these useful posts. I've followed this instructions and verified that the two last example *.vi work correctly.

I've a similar question: I'm trying to continuously generate and receive a chirp signal. But I have some problem, with underflow and Rx signal not as expected. I use 2 USRP2 boards and 2 XCVR2450 doughterboards, all synchronized via MIMO cable.

Could anyone help me in the following questions, please?

1. In the "00_USRP2_SetParam-FrontPanel.jpg"  is the correct way to set parameters, if I want to use a 6 MHz bandwidth of the chirp frequencies around the 5.4GHz carrier frequency?

2. The coerced RF BW appears always to be 24 MHz. This means that in fact the RF BW of the transmitted chirp is always 24 MHz and my 6 MHz setting is ignored?

3. In the "01_USRP2_chirp_generation.jpg" there are 3 different way I tested to generate the chirp signal, but to me is not so clear which one is the best one. Could you please tell me if you can see which one is the best way?

4. Is it correct in the "B" and "C" cases to use "0 GHz" to "TX RF BW" as band of the chirp of I have to use the "Carrier Frequency-(RF BW/2) GHz" to "Carrier Frequency+(RF BW/2) GHz" settings?

5. In the "01_USRP2_chirp_generation.jpg", which is the correct signal to send to the "niUSRP Write Data.vi"? The double array ("Y") or the waveform (generated with Y and dt) or the cluster (generated with Y and dt)?

6. Is the decimation necessary in all "A", "B" and "C" cases?

7. Is the "02_USRP2_TxRx_chirp_continuous.jpg" the correct way to continuosly Tx and Rx the chirp?

Sorry for the large number of questions... I'm new on using these devices...

Many thanks also if only some of the questions would be answered.

Giube

[4Matted]

Giube,

This seems like it would be best in it's own thread. The reason for this is it will allow the community to use the potential resolution to this issue for their benefit. If we leave this issue in this thread it will make it harder for future community members to use. Thank you.

[giube]

Ok, I opened a new thread "USRP chirp waveform".