초록 ▼

If a code is transmitted at a first transmission rate, a base station modulates the entirety of the code, namely a preamble, a synchronizing signal and a call-data, by two values and transmits them at the first transmission rate. If the code is transmitted at a second transmission rate, which is dou

If a code is transmitted at a first transmission rate, a base station modulates the entirety of the code, namely a preamble, a synchronizing signal and a call-data, by two values and transmits them at the first transmission rate. If the code is transmitted at a second transmission rate, which is double the first transmission rate, the base station modulates the preamble and the logically inverted synchronizing signal (obtained by inverting the “1”, “0”logic of the original synchronizing signal) by the two values, transmits them at the first transmission rate, modulates the call-data by four values and transmits it at the second transmission rate. As a result, it suffices to provide the pager with a single common preamble detector and a single common synchronizing detector, irrespective of the transmission rate. Moreover, by detecting the synchronizing signal or its inverted version, it is possible to determine whether the call-data has been modulated by two values or four values, thereby assuring that the call-data following the synchronizing signal can be modulated correctly.

대표청구항 ▼

A code transmission system in which a code comprising a preamble and a plurality of batches, in which each of the plurality of batches is constituted by a synchronizing signal and one or more call-data, is transmitted from a base station to portable pagers each of which notifies its possessor of a c

A code transmission system in which a code comprising a preamble and a plurality of batches, in which each of the plurality of batches is constituted by a synchronizing signal and one or more call-data, is transmitted from a base station to portable pagers each of which notifies its possessor of a call if an address contained in the call-data agrees with its own address, wherein: in a first case where the code is transmitted at a first transmission rate, the base station modulates the entirety of the preamble, the synchronizing signal and the call-data in the code by n values (where n is an even number) and transmits them at said first transmission rate, whereas in a second case where the code is transmitted at a second transmission rate that is double said first transmission rate, the base station modulates the preamble and the synchronizing signal in the code by the n values, transmits them at said first transmission rate, modulates the call-data by (n+2 m) values (where m is a natural number) and transmits it at said second transmission rate; and each of the portable pagers performs detection of the preamble and synchronizing signal on the basis of the fact that modulation is by the n values and transmission rate is said fast transmission rate, and receives the ensuing call-data based upon this detection.