How do we achieve and Continuous phase FFSK modulation with unsymmetrical deviations using labview and RFSG/RFSA combination?

[Sunilrajanna]

We need to receive a signal that is of Continuous Phase Fast FSK using the NI Lavbiew and RFSA PXI 5660.
The following are the details:


Carrier Freq= 457.9375Mhz

Mark(1)= 1200Hz
Space(0)= 1800Hz

Data rate=1200 Bits/sec

The issue that is presently at hand is, we do not have a standard vi or function to do this in labview.

[Teigen]

Sunny,

The FSK examples that are installed with the Modulation Toolkit for LabVIEW are the best starting point for creating the application that you have mentioned. Those examples can be found in the directories displayed in the attachment below.

Regards,

Scott Teigen
Applications Engineer
National Instruments

[Sunil Rajanna]

Hi Scott Teigen,

Sorry that I did not reply earlier, did not visit the forum for long.

We were studying out DUT and found out that the method of modulation we need to actually work on was FM. The message bits are converted to continuous phase baseband FM signal using a chip, this signal is then upconverted to the 457.9375Mhz. Now our work has shifted to FM based vis.
The problem that we are now facing is that of converting our message bits to basedband frequencies in the following format:

Mark (1) = 1200Hz
Space(0) = 1800Hz

For the sake of testing, we have generated a waveform manually to resemble an FM Baseband with deviation of 300hz, that is 1200Hz and 1800Hz (the carrier maybe assumend to be 1500Hz). All that we now need to do is upconvert this baseband to our Tx frequency. we are trying to do this. Presently we are manually converting the waveform data to a suitable format needed by the niRFSG write Arb waveform.vi (which upconverts and writes into the Fgen for transmission at our carrier frequency).
We have not been successful as yet, we feel our method of conversion or something is missing in our conversion process.
We request a possible solution to this. I once again shall mention needs for clarity.

We have mapped message bits to form a continuous phase waveform consisting of 1200hz and 1800hz, this is now our FM baseband waveform, so no further FM modulation of this signal is required. This baseband waveform is now just to be upconverted to our carrier freq of 457.9375Mhz (just a multiplication operation of the two freqs).
We are looking for methods to do this.

Thanks and regards,
sunil