Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing the width of top slab by reducing the inclination angle of the webs, and using a softer fastener on the track, were found to be effective and practical for reducing the noise generated by high-speed trains.
Figure 21 shows the average segmental SNR for the music signal as obtained by ten noise reduction methods, which are the combinations of two noise subtraction methods and five frequency analysis methods in an analysis frame.
In order to objectively evaluate the performance of the different diffusion algorithms, we adopt two noise-reduction measures: peak signal-to-noise ratio (PSNR) and the universal image quality index (UIQI).
Figure 2 illustrates the deficiency U ( i, j ) ( t ) = X ( i, j ) ( t ) − X ( t ) between the full process and all possible two noise source reductions X ( i, j ) on the 3-state chain, as projected onto each of the three components in the system.
A suction muffler used in a fluid machine has three functions: noise reduction; minimizing pressure drop and improving energy efficiency using acoustic effects.
JVC's proprietary Gigabrid Engine also contributes to quality by incorporating six digital noise reduction systems to improve the S/N ratio by about 30percentt (3dB) over previous models, and integrating the MPEG-2 encoder to help reduce block noise and mosquito noise.
Two strategies for noise reduction are proposed: filtering and thresholding.
Levels 2 and 4 were evaluated to assess differences between two less extreme noise reduction levels.
This shows that the two approaches for noise reduction are identical.
Simply put, the performance of speech enhancement methods can be assessed in terms of two quantities, namely noise reduction and speech distortion, and an optimal solution to the speech enhancement would, thus, explicitly take both into account.
