General Transmitter Design Based On Software Radio

With the fast developing of the wireless communications technology, the traditional hardware-based, facing to purpose radio design method gradually shows the limitations, and the poor compatibility and bad interoperability, versatility between the different communica-tion systems, gradually becomes constrained further obstacle to the development of radio.Software radio technology design methods transmitter came into being, the transmitter can support a variety of carrier frequency, and multiple modulation, and the modulation parameters, transmission rate and other parameters can be sent by the host computer, the source side can support different rate of the input source, the RF-side can communicate with the multi-band receiver, which shows a strong universal performance.The transmitter mainly divided into two parts, the master computer control interface and base band signal processing, of which communicate via the RS232bus. The master computer control interface designed by VC++6.0, by which complete the design of the interface, mainly to complete the control data selecting and sending. Base band signal processing section completes control data receiving and processing digital base band signal modulation, using the "A/D-FPGA-D/A’universal hardware platform, in which using of hardware languages on this platform to achieve the FM/BPSK/QPSK multi-rate modulation mode, enhanced compatibility and interoperability with different communication systems, which has become a direction of development of a new generation radio.First this paper introduces the basic concepts and overview of the wireless transmitter; second introduce the FM/BPSK/QPSK modulation section and the theoretical basis and algorithm; third, introduce simulation of the FM/BPSK/QPSK modulation procedures, hardware design, and the last in hardware debugging part of the performance indicators.