关键词: 现场可编程门阵列, 语谱图, 短时傅里叶变换, 非线性变换, 伪彩色

Abstract: In the current research and design of spectrogram based on Field Programmable Gate Array (FPGA), the direct indication of the spectrogram is not able to reflect the detail variation of spectrum. To solve this problem, a method for the display and enhancement of spectrogram based on FPGA was proposed in this paper. With nonlinear transformation, the high-resolution gray image was compressed to low gray-resolution image, so the detail variation of spectrum would be better reflected. Meanwhile，human vision is less sensitive to the difference between gray-scale pixels than that of colors, so with pseudo-color processing of the gray images, the results are displayed through Video Graphics Array (VGA). The experimental results show that more detail variation of spectrum can be obtained by the method.

Key words: Field Programmable Gate Array (FPGA), spectrogram, Short Time Fourier Transform (STFT), nonlinear transformation, pseudo-color