在基于FPGA的时频分析研究设计中，针对直接显示的时频谱图无法体现频谱细节变化的问题，提出了一种适合硬件实现的谱图增强算法。该算法以正弦信号的频谱结构为原型，选用反比例函数逼近正弦信号的频谱包络，并结合实际应用情况推导出具体的增强算法，利用该算法不仅对时频谱图的灰度级进行了压缩，而且进行了谱图增强处理。实验结果表明，此算法可有效显示出时频谱图的细节变化，与对数变换相比，具有运算量小，实时性好，适合硬件实现等特点。%During the research and design of time‐frequency analysis based on FPGA , the direct indication of the time‐frequency spectrogram is not able to reflect the variation of spectrum in detail . To solve this problem , an image enhancement algorithm of time‐frequency spectrogram based on FPGA is presented in this paper . The algorithm takes sinusoidal signal spectrum structure as design prototype , chooses the inverse proportion function to approximate the spectral envelope of sinusoidal signal , combines with the practical application to derive the specific enhancement algorithms . T he algorithm can not only compress the gray level of time‐frequency spectrogram , but also enhance the image . Experimental results show that more detail variation of time‐frequency spectrogram can be obtained by the algorithm effectively . Algorithm in this paper has the characteristics of much less computation , strong real‐time property and suitable for hardware implementation compared with logarithmic transform .
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