Carrier wave detection system for digital telecommunication signal - uses estimator squaring device and determines differences between even sample pairs and odd sample pairs and determines power level for comparison with threshold

摘要

The system includes a device which squares the complex envelope of a digital signal. Differences between uneven ad even samples in the squared complex envelope are determined and stored. The energy of the stored differences is determined. The output is divided into two paths. A first path takes the difference (34,36) between the even sample pair and the second path takes the difference (33,35) between the odd sample pair. The total power level (41) is calculated from the two paths. Comparison (42) of the level with a threshold level (S) allows determination of the presence or absence of the signal to be made.