Abstract
The system is based on fast Fourier transform (FFT) algorithm to AT89S52 MCU and FPGA for the control and data processing core, combined with the necessary external circuit, the frequency range of 200Hz ~ 10KHz audio signal frequency component analysis.To MCU as the main control device, the signal conditioning, signal processing, sampling andDFT algorithm components.Signal conditioning and 12-bit A / D with guaranteed accuracy.After signal acquisition to the FPGA's internal RAM memory in the rotation factor to quantify the ROM to store FPGA, the use of address generator and twiddle factor will be sampling the signal timing under certain multiply accumulate, high-speed precision DFT algorithm is completed.System control and operation by the core, programmable amplifiers, filtering, and sampling and other modules.Through the programmable gain amplifier to adjust the system can measure voltage (peak - peak) of the dynamic range defined as 100mV ~ 5V; by changing the ADC sampling frequency, to achieve frequency resolution 100Hz; spectrum analysis results can be stored sequentially,and use real-time dot matrix LCD display; by spectral data feature extraction determine the periodic signal, and to realize the distortion of the signal analysis.In addition, through the dot matrix LCD screen to graphically display the signal of each frequency component and its relative size.
Keywords: frequency domain analysis, FFT, frequency components, resolution, periodic