Method and apparatus for evaluating noise level on a telephone channel

摘要

The level of the signal present on the telephone channel is evaluated at successive time intervals. Those evaluated signal levels which lie within a given range of noise levels are selected and they are expressed in terms of r discrete values in said range. A count is maintained for each of said discrete values indicative of the frequency with which it is selected in comparison with the frequency with which the other discrete values are selected. The discrete value having the highest count, i.e. the most frequently selected discrete value, is considered to be indicative of the level of noise on the telephone channel in question.