AM with PXI-5671 and PXI-5661

[Raine]

I want to use the PXI-5671 and PXI-5661 modules to do an experiment with amplitude modulation, but I have made little progress.  My first problem is on the Tx end trying to create the modulating waveform to feed into the "Modulate AM" vi that came included with the Modulation Toolkit.

I want to be able to pick a file on the controller hard disk and use its raw binary data in order to create a square modulating wave.  So for example...

1. I pick a file, and let's say the first byte of data of that file is 10110000
2. I set my modulating frequency as 1MHz, and produce a square wave that has starts with an amplitude of "1" and holds for a microsecond, then "0" for a microsecond, then "1" for 2 microseconds, then "0" for 4 microseconds
3. The AWG is loaded with this waveform data and the carrier is modulated
4. Repeat steps 1-3 until the file is completely transmitted

Can this be done in a way such that the carrier is modulated seamlessly in time?  The experiement doesn't require that the conversion of data/loading of the waveform be done byte-by-byte, the main thing is to preserve the stream...

[Matt_A]

Hello Raine,

For more information about streaming RF data I would recommend you check out the Streaming Gateway online here. There are a lot of great resources on this webpage, including this tutorial on High-Speed Data Streaming for IF and Baseband Signals and this example program, which demonstrates RF Record and Playback.

However, it sounds like you are just trying to transmit and receive a binary file using the PXI-5671 RF Vector Signal Generator and PXI-5661 RF Vector Signal Analyzer, respectively. If this is the case, I would recommend that you examine the examples called Write Waveform From File.vi and RFSA Stream Binary IQ Data to Disk.vi. Write Waveform From File.vi reads data from a file in chunks and generates it using the PXI-5671. The other example, RFSA Stream Binary IQ Data to Disk.vi, acquires IQ data using the PXI-5661 and then streams the data to a file. These examples can be found in the NI Example Finder. You can open this utility in LabVIEW by going to the Help menu and selecting Find Examples... The NI-RFSG example (Write Waveform From File.vi) can be found at Hardware Input and Output>>Modular Instruments>>I-RFSG (RF Signal Generation) >>Modulated Waveform Generation; the example for NI-RFSA (RFSA Stream Binary IQ Data to Disk.vi) can be found at Hardware Input and Output>>Modular Instruments>>NI-RFSA (RF Signal Analyzer)>>Modulation Domain Analysis.