An FPGA-Based Digital Modulation Signal Generator with Fading Channel Emulation

In this paper, an FPGA-based digital modulation signal generator with fading channel effect is presented for basic experimental usage. Instead of using off-the-shelf but costly instruments to test various communication systems, this FPGA-based signal generator is more cost-effective. We use Altera Stratix EP1S25 DSP development board as the hardware platform, which can be rapidly and flexibly re-configured and re-programmed by modifying its Verilog-HDL code. Moreover, based on the software defined radio concept, some built-in functions have been included, such as three switchable basic digital modulations (BPKS/QPSK/8PSK), poly-phase square-root raised cosine pulse shaping, AWGN generator, complex Rayleigh flat fading channel, and I/Q modulator based on a reduced-memory DDFS. Some implementational and measurement results are also included.