Direct Digital Synthesizer

Documentation

• Direct Digital Synthesizer

Device Family Support

• Virtex-4 FX
• Virtex-4 LX
• Virtex-4 SX
• Virtex-II Pro
• Virtex-II
• Virtex-E
• Virtex
• Spartan-3E
• Spartan-3
• Spartan-II
• Spartan-IIE

Direct Digital Synthesizers (DDS), or numerically controlled oscillators (NCO), are important components in many digital communication systems. This DDS features sine, cosine, or quadrature outputs, sine/cosine table depths from eight to 65536 samples, 4-bit to 32-bit output sample precision and Xilinx Smart-IP technology for maximum performance. The core has a phase dithering option that provides high dynamic range signals using minimal FPGA resources. The core has optional phase offset capability, providing support for multiple synthesizers with precisely controlled phase differences. This Taylor series corrected DDS uses a feed-forward correction algorithm to generate high-quality sinusoids.

Key Features

• 4-bit to 32-bit two's complement output sample precision (this is repeated in the text)
• Look-up table can be allocated to distributed or block memory
• Phase dithering and Taylor series correction option provides high dynamic range signals using minimal amount of FPGA resources. SFDR range is 18 dB to 115 dB
• Phase dithering removes the spectral line structure associated with conventional phase truncation waveform synthesis architectures
• Support for 1 to 16 independent channels
• High-precision synthesizer with fine frequency resolution