USRP Software Radio

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Regarding problem with


          I am working on project "Building of Networked system using NIUSRP". In Lab 2 part 1 we need to design which needs to take the input UART bit stream from transmitter vi and decode it. I expect Transmitter block to work like this " if i give a text input 'How are you?' it needs to take each alphabet look for its Ascii value convert in to 8 bit binary and then invert the bits and add 0's and 1's so as make it in UART bit format then it show in 4 bit decimal representation as output." According to the above concept the expected output of is "8 4 10 15 6 11 11 10 0 4 10 1 10 4 14 10 9 10 0 4 10 7 10 15 6 10 11 10 15 12 8." for input "How are you?".But for some some reason output of is " 5 5 5 5 5 5 5 5 5 5 5 5 5 0 0 0 0 0 0 0 0 ...". So, when i give this as input to receiver block i could see output as only " u u u u u u ...". instead of "How are you?". And more over i cant be able to edit block beacuse it is a pre defined block by National Instruments. So, any one can please figure out how can solve this?

                       Thank you,

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Hello sudheep,


The "Building of Networked system using NIUSRP" is part of a coarse developed at Stanford University by Dr. Sachin Katti. All of the VIs that are locked were done so by him when creating the Labs for students to work through. These were not programs or VIs developed by National Instruments, and as a result we do not have the password to unlock them for you.


If you are a professor, student teacher, or researcher looking to use this specific example as a starting point, you can email Dr. Sachin Katti or someone in his lab directly to get the passwords. If you are a student working on this lab for a class, your professor most likely knows the password and is keeping the VI locked because it is not a component that should be edited during the lab or because he does not want to expose solutions to the class.


The reason you cannot edit the is because you most likely are not supposed to as part of the Lab.  As a result, most likely the logic that you are using in the needs to be  modified. The output of the corresponds to the output bitstream of "How are you?". So the expected output of the VI that you should be feeding into the is supposed to be what you have listed as the current result followed by a lot more values all either 0 or 5. These are representing the binary bits of information that you are gathering into bytes with the state machine that is part of the template. As part of the template, there is also a that is included that you will feed the bytes into that will translate the bytes into the ASCII character numeric values that you are listing as your expected result.


In case you were not provided with the template, I have included a link to the online lab here so that you can download the Lab 2 Digital Communication to use as a reference.


I hope that this helps!

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