Full duplex frequency division multiplex communication system
First Claim
1. A duplex frequency division multiplex communication system comprising:
- a plurality of user stations intercoupled by a common communication channel, a first frequency converting means coupled to said common channel for shifting the carrier frequencies of the signals introduced to the common channel by all of the user stations by a particular frequency differential for reception by the user stations, each of said stations comprising a transceiver and each transceiver comprising;
a source of information signals;
modulating means coupled to said source for modulating said information signals on a first carrier of a particular frequency;
second frequency converting means;
first means for applying the first modulated carrier from said modulating means to said second frequency converting means to shift the first carrier to a selected channel frequency;
second means coupled to said second frequency converting means for introducing the output from said second frequency converting means to said common channel;
third frequency converting means;
third means for introducing signals from said common channel modulated on a second carrier of a particular channel frequency to said third frequency converting means, said second carrier having a frequency displaced from the frequency of said first carrier by said particular frequency differential;
demodulating means;
fourth means for applying output signals from said third frequency converting means to said demodulating means to recover the signals modulated on the second carrier; and
information reproducing means coupled to said demodulator means.
0 Assignments
0 Petitions
Accused Products
Abstract
A full duplex frequency division multiplex communication system which comprises a number of transceivers constituting user stations which communicate with one another over a common channel, such as a wireless link or a two-direction coaxial cable, with each transceiver operating on a single fixed intermediate frequency for transmission and reception. The system includes a network frequency converter for shifting the transmission frequency band used by the transceivers into a different receiving frequency band which does not overlap the transmission frequency band. Single sideband modulation of the intermediate frequency carrier is used, and full duplex communication is achieved by using one of the sidebands of the intermediate frequency carrier for transmission, and the other sideband for reception. Each transceiver includes a programmable frequency synthesizer for channel selection, and upper and lower sideband filters, with one of the filters being used for transmission and the other for reception.
303 Citations
8 Claims
-
1. A duplex frequency division multiplex communication system comprising:
- a plurality of user stations intercoupled by a common communication channel, a first frequency converting means coupled to said common channel for shifting the carrier frequencies of the signals introduced to the common channel by all of the user stations by a particular frequency differential for reception by the user stations, each of said stations comprising a transceiver and each transceiver comprising;
a source of information signals;
modulating means coupled to said source for modulating said information signals on a first carrier of a particular frequency;
second frequency converting means;
first means for applying the first modulated carrier from said modulating means to said second frequency converting means to shift the first carrier to a selected channel frequency;
second means coupled to said second frequency converting means for introducing the output from said second frequency converting means to said common channel;
third frequency converting means;
third means for introducing signals from said common channel modulated on a second carrier of a particular channel frequency to said third frequency converting means, said second carrier having a frequency displaced from the frequency of said first carrier by said particular frequency differential;
demodulating means;
fourth means for applying output signals from said third frequency converting means to said demodulating means to recover the signals modulated on the second carrier; and
information reproducing means coupled to said demodulator means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- a plurality of user stations intercoupled by a common communication channel, a first frequency converting means coupled to said common channel for shifting the carrier frequencies of the signals introduced to the common channel by all of the user stations by a particular frequency differential for reception by the user stations, each of said stations comprising a transceiver and each transceiver comprising;
Specification