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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. Between 4-point and 32768-point FFTs may be performed, the upper limit depending on data-memory availability. The FFT decimates in time, the computations being done in place with full intermediate scaling and 0.5lsb rounding.
         Routine calls are provided for: zeroing the FFT array, pre-computing the "twiddle factors", 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 example application files are provided with the code. Test results are available.

Processor Load:

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

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