Current Industry Benchmarks for 1-D 1024-point FFT calculations |
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Device |
Clock Speed |
FFT-type |
Process time (cycles/ processor speed) |
Estimated process time for 1024 x1024 2-D FFT calculation |
| Texas Instruments DSP TMS320C67x series | 1GHz | Mixed radix | 14.464µs | 29.62ms |
| Xilinx FPGA Virtex-4 4sx25 | 500MHz | Pipelined Streaming | 2.08µs | 4.26ms |
CCL Process Times
For Optical Fourier Transforms using the CCL technology, the process time is limited by the switching speeds of the liquid crystal used in the SLM. For greyscale devices, nematic liquid crystals are typically used, with switching speeds in the order of 10ms. Binary ferroelectric liquid crystals, however, operate at speeds of the order of 10μs. Development work on analogue ferroelectric devices promises megapixel greyscale frame rates of 1kHz in the near future.
Power comparison FFTvsOFT: 2FPGAs could be 100s of Watts,vs laser power+SLM+CMOS+interfaces around 1W.
Sources:
Texas Instruments website (www.ti.com)
Xilinx: “Fast Fourier Transform v3.20” product specification, S260, August 31st, 2005 Xilinx website (www.xilinx.com)