An interactive speaker testing system based on DFT

The paper discusses the analysis of a signal using fast Fourier transform (FFT). Fourier analysis is a mathematical technique based on decomposing signals into sinusoids. The discrete Fourier transform (DFT) is the technique used with periodic digitized signals. There are several ways to calculate the discrete Fourier transform, such as solving simultaneous linear equations, the correlation method and fast Fourier transform (FFT). While FFT produces the same result as the other approaches for calculating DFT, it is incredibly more efficient, often reducing the computation time by about three hundred times as compared to other DFT techniques. To demonstrate the practical aspects of fast Fourier transform, a speaker testing system is developed and different speakers are tested for buzzing. Buzzing is a common problem in speakers. To detect a speaker for buzzing, an interactive PC based system has been developed, and, using this system, a speaker can be easily analyzed. Also, by using this system, the testing time is greatly reduced and the test data can be saved in the form of a graph of frequency versus % total harmonic distortion (THD). Both the hardware and the software for this system are discussed.