Teaching Rate Conversion Using Hardware-Based DSP

摘要

To enable us to affordably teach software defined radio at the undergraduate level, we developed a low cost system that allows realistic hardware projects and demonstrations. This new board connects a Texas Instruments C67x DSP starter kit (DSK) to an Analog Devices AD9857 quadrature modulator. This modulator is capable of operating at up to 200 million samples per second (MS/s), with a carrier (or intermediate frequency) of up to 80 MHz. Baseband 14-bit in-phase and quadrature (I/Q) data are presented to the modulator, which can be programmed to interpolate the data at rates from 4 to 252 . The AD9857 is interfaced to the DSK using an Altera Cyclone FPGA which provides queuing of the I/Q data and the logic for control/programming of the modulator. This paper describes the associated hardware and software issues and briefly describes recommended classroom use.