| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a signaling system which can be used to update the prices of goods which are electronically displayed on supermarket shelves. <P>SOLUTION: The signaling system comprises a first signaling device having an input terminal for receiving electrical message data from a central computer system 5, a spread spectrum encoder for encoding the received message data and an electroacoustic converter 11 for converting the encoded data into corresponding acoustic signals and for transmitting the acoustic signals into a transmission medium. The signaling system also comprises a second signalling device 3 having means for receiving acoustic signals from the transmission medium and for converting the received acoustic signals into corresponding electrical signals, a spread spectrum decoder for decoding the received signals and a message regenerator for regenerating the message data transmitted by the first signalling device from the signals output by the decoder. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
