| 摘要 |
A method of calculating noise level in a signal, comprising the steps of accumulating two sample windows of the signal, calculating energy of the signal within each of the sample windows, calculating the difference in the energy of the signal within each of the sample windows, updating a variance parameter based on the difference, in the event that the variance parameter is less than a predetermined multiple of the energy of the signal within a most recent one of the sample windows then indicating the presence of noise and setting a noise level parameter as a function of the energy of the signal within the most recent one of the sample windows, and in the event that the variance parameter is greater than or equal to the predetermined multiple of the energy of the signal within the most recent one of the sample windows then indicating the absence of noise, and in the event the noise level parameter exceeds the energy of the signal within the most recent one of the sample windows then setting the noise level parameter to equal the energy of the signal within the most recent one of the sample windows.
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