Digital cordless telephone systems
First Claim
1. A digital cordless telephone system comprising a primary station and a secondary station, each said station comprising a transceiver whereby digitised speech communication is established on a time division duplex channel, and means in at least the primary station for producing a beacon signal comprising a data signal having a data rate substantially less than the digitising rate of the speech signal.
3 Assignments
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Accused Products
Abstract
A digital cordless telephone system which comprises a primary station (PS) controlled by a system controller (14 or 15) and a plurality of secondary stations (SS) capable of communicating with the primary station by way of a time division duplex radio link, the primary and/or secondary station having means to generate a beacon signal which is receivable by a secondary station outside the range of normal speech communication and the beacon signal comprising a low bit rate signal which is transmitted at a power comparable to the digitized speech signal. In one embodiment the beacon signal is recovered using a narrowband filter and a demodulator. In another embodiment direct sequence spread spectrum techniques are used to send the beacon signal and a correlator/matching circuit is used to recover the low bit rate data representative of the beacon signal.
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Citations
13 Claims
- 1. A digital cordless telephone system comprising a primary station and a secondary station, each said station comprising a transceiver whereby digitised speech communication is established on a time division duplex channel, and means in at least the primary station for producing a beacon signal comprising a data signal having a data rate substantially less than the digitising rate of the speech signal.
Specification