公开(公告)号：EP0394357B1

公开(公告)日：1995-09-06

申请号：EP89901806.3

申请日：1988-12-12

申请人： MOTOROLA, INC.

发明人： SIWIAK, Kazimierz ,  KEBA, James, M. ,  Steel, Francis Robert

IPC分类号： G08B5/22

CPC分类号： H04W84/025 ,  B63B21/48 ,  G08B3/1016 ,  H04L1/1829

摘要： An acknowledge back (ack-back) pager is provided for use in a paging system (100) including a central station (110) which transmits a group of message signals to a group of ack-back pagers (121, 122, ...) which are addressed as a group. The users of the group of addressed ack-back pagers (121, 122, ...) indicate a response to their respective pagers thus providing ack-back data. The pagers (121, 122, ...) in the group of addressed ack-back pagers then simultaneously transmit back to the central section (110) their ack-back data on different respective frequency sub-bands. To accurately control the ack-back transmit frequency each pager (121, 122, ...) receives and down-converts the FRX signal, selects a frequency sub-band within a predetermined range of frequencies, determines a frequency offset FD corresponding to the selected sub-band, and generates an acknowledge back signal and up-converts such signal to a transmit frequency FTX.