Figure 1:

Time-frequency resolution tradeoff inherent in different TF algorithms. STFT uses fixed time windows leading to an inflexible TF tradeoff. CWT, DCWT, and S-transform have increased temporal resolution at higher frequencies due to compression of a Gaussian function; the same occurs for filter-Hilbert as high-frequency filters have decreasing numbers of points. The Wigner-Ville distribution has excellent joint time-frequency resolution, but suffers from cross-terms that render it unusable for most practical applications. The Reduced Interference Distributions solve this problem by applying kernel functions to the Wigner-Ville distribution, significantly masking cross-terms at the expense of slightly lower TF resolution.