BER of 1

[johnmarry]

Hello!

I'm partially using the example on modulation demodulation for QPSK on LabView Communications, No USRP for now. I added BCH and LDPC coding and decoding, and wanted to calculated the error using the BER function. However the demodulator output bit stream is completely different than the transmitted one, and the BER is 1! How is that possible? I added sync bits at the begginning of the transmitted message, and used those sync bits with the generate synchronization parameters function, but I'm still getting different bits, and still a BER of 1 (never another value). I don't quite know what I'm doing wrong. Also, I'm losing about 50% of the transmitted bits, I don't know why (the demodulador is on reset each time). Attached is the GVI, is I could get some guidance on this it would be great, I'm not sure how to fix it and it's really a pressing matter

[tcap]

Hello John,

I took a look at your gvi, but I am missing one of the functions you are using.

I recommend removing all of the unused terminals, cleaning up the diagram, and adding comments describing each section of code. This will make debugging much easier, and it will help us help you more efficiently.

I recommend looking at the Learn>Programming Basics>Debugging Your VI lesson to get more familiar with the debugging tools available to you, such as Probes, Breakpoints, Single Stepping, and Highlight Execution. Using these tools, you will be able to determine the value of your data as it propagates through your program, allowing you to determine where the data being miscalculated.

Regards,

[tcap]

Hey John,

I created an example that does PSK Modulation and Demodulation. Please take a look at the attached VI.  The issue I faced while creating this example was configuring the message sync bits. This caused my BER to equal 1, because it never detected a message.

Regards,