Parallel to serial conversion for implementing FSK modulation on fpga

Question

I want to implement FSK modulation in LABview FPGA using the arithematic VIs. My bit rate is 625 kbps and sampling rate of the waveforms i utilize is 80 MHz.(for 0 i use 1.25 MHz and for 1 2.5 MHz). I want to take AUDIO input from computer and modulate it and then transmitting it into the air. Modulation has to be done in FPGA Vi. Now i want to convert the sample values coming at particular rate to bits (parallel to serial conversion) representing the samples these bits should come one by one at the rate of 625 kbps to select vi which would select the waveform depending on zero or one on its select port. I want to know how parallel to serial conversion can be done in labview
KAMRAN ZIA
UNGERGRADUATE STUDENT (AVIONICS)

Answer 1

Hi Kamran,
With respect to the first issue, it should be relatively straightforward to generate the signal you want. In your FPGA code, I would assume that you have a sine wave generator. In the configuration screen, you can elect to show the frequency terminal. you can generate a certain amount of data (whatever you require) and then when the FPGA loops again, generate the next section of waveform based on the bit you want to output.
a few documents on our website include:
http://zone.ni.com/devzone/cda/tut/p/id/3253
http://decibel.ni.com/content/docs/DOC-5412
http://forums.ni.com/t5/Real-Time-Measurement-and/Simple-FSK-signal-generation/m-p/783361?requireLog...
With respect to the second issue, there are many many ways to do it. I have attached a very basic example which shows you one such option. It takes a U8 (a single byte) and spits out each of the contained bits at 40 MHz.
Thanks,
D Smith
Attachments:
parallel to serial FPGA.vi ‏26 KB