| 摘要 |
<p>A system for recognizing degraded pseudo-random noise (PN) synchronization in a spread-spectrum receiver. The system uses a signal that indicates the correlation of the locally generated PN sequence with the received PN sequence. The correlation signal can be a symbol-length integration of the output from a square-law detector, or an appropriate similar signal. If the correlation signal is not degraded by demodulating with a deliberately shifted copy of the PN sequence, there is an indication that the unshifted PN sequence was itself not correctly synchronized. A sufficiently degraded correlation signal indicates that the receiver's PN synchronization is correct. To prevent the loss of transmitted data during the testing, each transmitted frame contains a Measurement field (that contains no payload data) for assessing the synchronization in this manner. The PN sequence is shifted only during this specific portion of the received frame.</p> |
