128点FFT F240.pdf

Application Report SPRA417A EVM Application #8 Implementing a Spectrum Analyzer Using a 128-Point FFT and the TMS320F240 EVM Dave Figoli Digital Signal Processing Applications Abstract Evaluation module (EVM) application #8 produces a spectrum analyzer using the digital-to-analog converter (DAC) of the Texas Instruments (TIä) TMS320F240 EVM. The spectrum analyzer is produced using a 128-point fast Fourier transform (FFT) with the values collected from the analog-to-digital converter (ADC). The output is produced using the DAC, and the results can be viewed using an oscilloscope and the XF pin as a trigger. The results of the FFT are normalized so that the maximum value obtained is equivalent to 5 V. This application is implemented using C2xx assembly code. The specific topic discussed is FFT implementation. Contents Overview 2 Modules Used2 Input 2 Output 2 Background and Methodology 2 FFT Implementation3 Digital Signal Processing Solutions June 1999 Application Report SPRA417A Overview This application produces a spectrum analyzer using the DAC of the TI TMS320F240 EVM. The spectrum analyzer is produced using a 128-point FFT with the values collected from the ADC. The output is produced using the DAC, and the results can be viewed using an oscilloscope and the XF pin as a trigger. The results of the FFT are normalized so that the maximum value obtai