wp file: polyphasecore.wpd

RF Engines starts licensing Polyphase DFT cores as IP

By John Walko, CommsDesign.com

May 19, 2003 (3:32 AM)

URL: http://www.planetanalog.com/story/OEG20030519S0007

London — Signal processing specialist RF Engines Limited (Isle of Wight, UK) has added high-speed Polyphase DFT (discrete Fourier transform) cores to its range of DSP technologies. Dubbed the Ventrix range, the core is intended for applications where filter performance and processing speed are critical and optimal use of the available silicon is required. They provide advancec filter banks to process complex input data in continuous real time with no gaps in data, at rates of up to 800 mega-samples per second or more.

"Polyphase DFT technology has been around for a while and is used in the communications sector and as a digital IF replacement, but we think we are the first to have packaged it as a commercial piece of IP that is fully tested and characterized," said John Summers, vice president of sales and business development at RF Engines.

The Polyphase DFT cores are pipelined for maximum data throughput and, according to the company, provide significantly better filter performance compared with weighted FFT techniques, giving better in-band ripple, stop-band rejection and roll-off.

Applications for the Ventrix designs include wide-band filter banks, communications systems, real-time spectral analysis and multi-channel systems, where many low speed channels are interleaved through the high-speed core.

The highly optimised pipelined polyphase core incorporates RF Engine's FFT core, and there are versions from eight to over 1 million points. Custom filter design techniques allowed the company to design very high specification filters of almost any length for use within the Polyphase DFT. Critically sampled, twice oversampled and "n" times oversampled versions are available. The 10-bit, 3 tap, twice oversampled 16K-point version fits in a single Xilinx XC2V3000 Virtex FPGA. Designs have shown that a real-time 1 million point, 5-tap, 14-bit, 20 MHz complex data rate, version fits in a single XC2V6000 and three external SDRAMs.