This VI continuously fetches data from the USRP until energy of a specificed trigger level (default is 0.002) is achieved. At that point it gathers the specified number of samples including a pretrigger of aa designated number of samples (Ref level default is 5%). If the number of samples is not available in the buffer, another fetch is performed and combined with the first bugger before results are returned.
This results in an acquistion loop that runs continuously, providing data only when an event occurs.
(This is the same trigger code used in the 6x6 MIMO example, modified for the single channel case.)
This code is provided courtesy of Jackson Massey.
*Please cite this paper if you want to build on this code and publish something with it.
Trigger on Energy Example LabVIEW Communications System Design Suite
The second zip folder is the Simple Trigger on Energy Example implemented in the LabVIEW Communications System Design Suite environment. This code has the same functionality as the previous version; however, you will need to install LabVIEW Communications System Design Suite in order to run this code.
The front panel of the Trigger on Energy Example.gvi contains the parameters for the NI USRP receiver and the trigger level. Set the controls of these parameters with the following guidelines in mind: