This paper presents an framework for efficient design and implementation of software defined radio (SDR) on FPGA platform using optimized Quadrature Direct Digital Frequency Synthesizer (QDDFS). An basic SDR System consists of RF Antennas, Analog to Digital converter (ADC), Digital to Analog converter (DAC), Filters and processing units.Reconfigurability and optimization can be achieved in the processing unit to a maximum extent. Processing unit of the SDR System is designed and implemented completely in this paper. The important parts of the SDR system designed are 16-Quadrature Amplitude Modulation (16-QAM), Orthogonal Frequency Division Multiplexing (OFDM) (16 point Fast Fourier Transforms (FFT), Inverse Fast Fourier Transform (IFFT) and Cyclic Prefix) and QDDFS. QDDFS generates the sine and cosine values in digital domain and it is optimized in terms of the device utilization with efficientperformance and the functionality of rapidly hopping between the different frequencies, faster response time are also achieved. Both in transmitter and receiver, the same QDDFS architecture is used. The Input to the SDR system designed is Text Data which is fed and retrieved in the ASCII Format.

This paper presents an framework for efficient design and implementation of optimized Quadrature Direct Digital Frequency Synthesizer (QDDFS) for software defined radio (SDR) on FPGA platform. SDR are radios that provide software control of a variety of modulation techniques over a broad frequency range. QDDFS generates the sine and cosine values in digital domain. QDDFS is optimized in terms of the device utilization with fine resolution in terms of phase and frequency. and also to rapidly hop between the different frequencies, thus improving the efficiency of SDR. In modulation, Proposed QDDFS has structure which utilizes less resource on FPGA and in demodulation same architecture is used to retrieve back the digital data. The proposed QDDFS is optimized than the Coordinate Rotation Digital Computer (CORDIC) technique, Look-Up Table based (LUT) QDDFS.