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FFT Time-to-Frequency DSP C Code

Description: this routine performs the tasks involved in FFT spectral analysis ie a complete time-to-frequency FFT on an N = 2ˆM time sample array in one call. The FFT conversion is programmable from 4- to 16384-points. The FFT decimates in time, the computations being done in place with full intermediate scaling and 0.5lsb rounding. The main FFT routine is also programmable for FFT conversion in stages. This can be useful for spreading the processing load in a real-time system.
         Routine calls are provided for: zeroing the FFT array, pre-computing the "twiddle factors", loading the array with bit-reversed addressing, performing the FFT, and converting the output spectra real and imag parts to magnitudes. Optionally, the FFT computation may be done on: real and imag time samples or on real samples only, both with pre-stored twiddle factors, or on real and imag time samples with twiddle factors calculated on-the-fly. These options give various trade-offs between cycles taken, data memory required, and program memory used.
         The C code is suitable for any processor with an ANSI-compliant C compiler. It is designed especially for efficient operation on low-cost fixed-point DSP- and general-purpose micro-processors. All data memory is specified as 16-bit integer words. Multiplies are integer 16x16-bit with 32-bit products.
         The code is re-entrant so multiple channels can readily be processed. A comprehensive user's guide, together with test results and an example application file, is provided with the code.

Processor Load:

- #example figures from compiling for the TI TMS320C5000(C55x) DSP processor

Availability: NOW, sale is under licence - integration support offered