Hello,
I have been trying to synchronize two N200 USRP (Receiver and Transmitter) using GPSDO toolkit + GPS antenna. I am using niUSRP EX PSK TX and niUSRP EX PSK Rx example file (Labview 2011) at the transmitter and receiver end. I have been using following step:
[1]. Used the aforementioned labview example files without any modification as step no 2 of Instructions provided in ( https://www.ettus.com/content/files/gpsdo-kit_4.pdf ) clearly mentions that changing J510 jumper on motherboard from 1-2 to 2-3 switches external 10 MHz Ref Clock to GPSDO’s 10 MHz Ref Clock. I assume that the hardware change made in the Ettus’ N200 USRP box while installing the GPSDO toolkit is enough to let the Labview program to know about where its reference clock signal is coming from.
[2]. I made some modification to the labview file (both TX and Rx) by adding a property node which selects “Reference Frequency Source” and added a controller which selects it as internal as shown in the attachment_freq.
[3]. Similar to (2), I made some modification to the labview file ( both TX and RX ), this time around by adding a property node which selects “Time base clock Source” and added a controller which selects it as internal as shown in attachment_time.
à Point to be noted while performing this entire step (1, 2 and 3) was:
"The labview program works perfectly fine when no GPS antenna is connected to the GPSDO output of the N200 USRP. As soon as I connect the antenna to the USRPs, it throws error as shown in attachment_error"
So, my questions are directed towards these are:
[A]. What does the error actually mean?
[B]. What has the error to do with connection or disconnection of the GPS antenna to GPSDO tool-kit?
[C]. My objective is just to update both devices that the Ref-clock signal is coming from the same source ( as a mode for synchronizing both devices). I am using Ettus’ GPSDO clock with GPS antenna for that purpose. Since, my modification in program in step2 and step3 doesn’t work well. I would want to know how you incorporate that with labview. Is not there any example VI in labview that uses previously mentioned product to synchronize?
[D].What does the labview program takes as a Ref-Clock source as default ?
