| 摘要 |
<p>In digital communication systems such as digital paging, alpha-numeric messages are normally encoded character-by-character using say the ASCII bit character set. The number of bits concerned in sending such messages can be reduced by arranging the primary and secondary stations in a communications system to have ROMs which store a common dictionary. If a word to be sent is stored in the ROM then its location address is transmitted as a 7-bit character pair. However, if a word is not present in the ROM then it is encoded using ASCII characters. The data field (DF) of the transmitted message signal is preceded by and concatenated with a command and control field (CCF) which includes an indication that word compression has been used and indications which can be used by a receiver to determine when the ASCII characters begin and end in the data field.</p> |
