The second problem of SMVAD also occurs on the low-powered frequency region of the noise.
When speech component exists in the current frame, the LLRs in the high-powered frequency region obtained because of the speech component may show high value.
In Figure 3c, it is also observed that most of LLRs are close to 0 and high LLRs are located on the most high-powered frequency region.
When speech component exists in the current frame, the LLRs in the high-powered frequency region obtained because of the speech component may show high value. .
As already mentioned, in most high-powered frequency regions, the variances of a posteriori SNR are very close to 0, which means that there are low possibilities of high LLR values.
By considering two undesirable phenomena analyzed in Section 3, it is discovered that LLRs in the high-powered frequency region are more reliable than those in the low-powered region.
The results also demonstrate how electrothermal-powered frequency tuning is affected by the surface conditions of the beam, which results in the determination of the tuning ratio's stability and linearity, based on the input power.
In the noise-only frames, the average of LLRs has to be close to 0. However, the a posteriori SNRs in low-powered frequency region can be high and possibly make certain LLR values as high as the levels in the speech frame.
From the investigation of the first problem, it is concluded that the decision rule of SMVAD uses LLR at every frequency bin but not all of them contribute to a correct decision in case of the components in the low-powered frequency region.
However, since the a posteriori SNR is the ratio of the varying input spectrum |Y k (n)|2 to the almost fixed noise variance, the a posteriori SNRs in the low-powered frequency regions are more difficult to be settled on fixed low values.
A solar powered high frequency electric discharge topology has been suggested that will improve the size and specific energy density required when compared to the traditional repetitive pulse or 50 Hz AC energization.
