FPGA Implementation of BASK-BFSK-BPSK Digital Modulators [Testing Ourselves]

Field-programmable gate-array (FPGA) implementations of binary amplitude-shift keying (BASK), binary frequency-shift keying (BFSK), and binary phase-shift keying (BPSK) digital modulators are presented. The proposed designs are aimed at educational purposes in a digital communication course. They employ the minimum number of blocks necessary for achieving BASK, BFSK, and BPSK modulation, and for full integration with the other functional parts of the Altera Development and Education (DE2) FPGA board. The input carrier signal and the bit stream (modulating signal) are user controllable. These digital modulators were developed and compiled to a Verilog Hardware Description Language (HDL) netlist, and were later implemented into an Altera DE2 FPGA board. The functionality of these digital modulators was demonstrated through simulations using the Quartus II simulation software, and experimental measurements of the real-time modulated signal via an oscilloscope.