Abstract: A cordless system comprises a laptop computer with a modem connected to a modem data port on a cordless telephone handset. A direct sequence spread spectrum RF link is established between the cordless telephone handset and a base station. Both the telephone network and a desktop computer with a modem are connected to the base station. When the cordless telephone handset detects that the laptop computer wants to go off-hook, a selection signal is also sent by the cordless telephone handset to the base station to indicate whether the call is to be directed to the telephone network or the desktop computer. When the base station detects that the desktop computer wants to go off-hook, a selection signal is also sent by the desktop computer to the base station to indicate whether the call is to be directed to the telephone network or over the RF link to the laptop computer.
Type:
Grant
Filed:
September 19, 1996
Date of Patent:
July 27, 1999
Assignee:
Wireless Logic, Inc.
Inventors:
Daniel Babitch, Andrew G. Varadi, James Wong
Abstract: A direct sequence spread spectrum (DSSS) radio communication system of the present invention comprises a transmitter and a matching receiver. The transmitter includes a pseudorandom number (PRN) code generator, a chip clock generator and a 16.times. clock generator that runs at sixteen times the chip clock rate. The output of the PRN code generator and chip clock generator are exclusive-OR'ed to derive a Manchester encoding of the DSSS spreading code. A tri-state buffer is used to deliver such Manchester encoded DSSS spreading code to a mixer to spread a biphase shift keyed (BPSK) radio carrier before being transmitted. The tri-state buffer can be a part of the exclusive-OR logic and is connected to place its output in a high impedance state one sixteenth of every chip clock period. This provides for a suppression of the spurious sidebands that otherwise limit adjacent channel packing.