| 摘要 |
<p>The speech detector for a telephone line concentrator operates in a system where the lines are sampled in a regular sequence. The detector assigns a value to each line between a lower limit of zero and an upper limit by sub-division of the total amplitude range into sub-ranges recorded by amplitude values of - 1, 0, 1, 2... These are added algebraically each time a new sample is taken giving a cumulative value. A threshold logic circuit (5, 9) receives this cumulative value (Nc) and provides binary information indicating the activity of the line when this value passes a given threshold, this threshold being between the two limits.</p> |
