| 摘要 |
In a data communication system an auxiliary communication signal is generated by applying On-Off Keying to a main communication signal of a wireless, optical or wireline communication system. The keying employs a gap position line-code by positioning silence intervals within the main communication signal, whereby the start- and end time of the interval depend on auxiliary data to be transmitted. During the positioned gap the main data that is transmitted over the communication signal is paused and the main communication signal is silenced. At the receiver, demodulation of the auxiliary channel is accomplished by detecting the power envelope of the received signal to determine the start-and end time of any gapping intervals, and the position of the interval is subsequently decoded to recover the auxiliary data. The auxiliary data stream is used as a more robust communication channel to overcome temporary heavy interference and fading during critical data transmissions, and it is used for wake-up calls and power management in the receiving device. |
