fsk(frequency shift keying) + fpga
Those are analog signals. FPGA are not well-suited for analog. You yould need external DAC/ADC. However, you could implement the DAC internally, with minimal external components, as a delta-sigma DAC (sorry, I originally wrote delta-epsilon...).
The application is more suited for a DSP. Though, it may be possible to implement in FPGA, this may be pretty complicated. FSK would be easier than QPSK. In both cases, you could, I guess, generate a sine wave at different frequency/phase, and select between the wave, and amplitudes, to generate. However, decoding QPSK is another story, this is really something that is usually done in an analog fashion, or with advanced signal processing.