Telecommunications – Transmitter and receiver at same station – With transmitter-receiver switching or interaction prevention
Reexamination Certificate
1997-04-30
2001-06-19
Chang, Vivian (Department: 2682)
Telecommunications
Transmitter and receiver at same station
With transmitter-receiver switching or interaction prevention
C455S552100
Reexamination Certificate
active
06249670
ABSTRACT:
BACKGROUND
The present invention relates to a signal combining device for a dual band radio having an antenna for use in a mobile unit in a cellular mobile radio communication system including at least one base station and/or for use in a satellite radio communication system. The present invention also relates to a method for combining signals in a signal combining device for a dual band radio having an antenna for operation in a cellular mobile radio communication system including at least one base station and/or for operation in a satellite radio communication system.
Radio communications systems typically operate using different frequency ranges. For instances, in the United States, the AMPS protocol may be designed to operate in the 824-849 MHz and 869-894 MHz ranges, while the PCS system may be designed to operate in the 1850-1910 MHz and 1930-1990 ranges. In addition, different geographic areas (e.g. states) may allocate different frequency ranges for use in radio communication.
Furthermore, in some instances, both analogue and digital forms of radio communication are used, providing “dual mode” radio communication. For example, digital Time Division Multiple Access (TDMA) systems can be used for reception and transmission of digital signals. Continuous transmission and reception is used for the transmission and reception of analogue signals.
SUMMARY
It is an exemplary objective of the invention to provide a device for use in a dual or multi band mobile radio for receiving and transmitting analog and digital electromagnetic information in different spectrum ranges using a single antenna.
It is another exemplary objective of the present invention to provide a device for use in a dual or multi band mobile radio using a common antenna which can be used in a digital mobile radio communication system for the 1900 MHz frequency range (e.g. for PCS 1900), and in an analogue mobile radio communication system for the 800 MHz frequency range (e.g. for AMPS 800).
These and other objectives are achieved in the present invention through the use of a signal combining device for a dual band radio, including an antenna which has a first and a second transmitting circuits and a first and a second receiving circuits connected to a device for matching. The device for matching is also connected to the antenna. The first transmitting circuit and the first receiving circuit are designed to transmit and receive, respectively, a digital signal, and the second transmitting circuit and the second receiving circuit are designed to transmit and receive, respectively, an analogue or a digital signal.
Another exemplary embodiment of the present invention provides a signal combining device for a multi-band radio communication system using a single antenna. This embodiment employs more than two transmitting and receiving circuits, respectively, which are connected to a device for matching, which in turn, is connected to the antenna.
According to another exemplary embodiment of the invention, a combining device can be used in a radio which can operate in the frequency range of 1850-1910 (e.g. the PCS band). The first transmitting circuit sends out information in this band. The same radio can also operate in the frequency range of 824-849 (e.g. the AMPS band). The second transmitting circuit sends out information in this band. In this embodiment, there is a frequency difference of 1001 MHz between the signal that the first transmitting circuit is designed to transmit and the signal that the second transmitting circuit is designed to transmit. Generally speaking, the present invention can be used in all dual band (or multi band) applications where there is a sufficient separation in bands.
According to more specific exemplary aspects of the present invention, a signal which is transmitted from the first transmitting circuit to the antenna passes through a first device for switching, wherein a first contact of the first device for switching and a second contact of the first device for switching are connected to the first transmitting circuit and to the antenna, respectively. According to several exemplary embodiments, a second resonance circuit is additionally interposed between the first device for switching and the antenna.
Advantageously, a signal transmitted from the second transmitting circuit to the antenna passes first through a first device for filtering and thereafter through the device for matching, and then to the antenna. The first device for filtering has a first contact connected to the second transmitting circuit and a second contact connected to a connection point located between the second transmitting circuit, the second receiving circuit and a first contact of the device for matching. The first device for filtering has a high reflection coefficient at the second contact of the first device for filtering at least for signals received by the second receiving circuit. The device for matching has, in addition to the first contact, a second contact which is connected to the antenna.
A signal received by the first receiving circuit from the antenna passes first through a first device for impedance transforming and then passes through a second device for impedance transforming, which is set to zero in several exemplary embodiments. Thereafter, the signal passes through a second device for filtering. Optionally, the second device for filtering can be omitted. The first device for impedance transforming has a first contact connected to the antenna and a second contact connected to a first contact of the second device for impedance transforming. The second device for impedance transforming has a second contact which is connected to a first contact of the second device for filtering. The second device for filtering has a second contact which is connected to the first receiving circuit. A second device for switching has a first contact connected to a connection point between the second contact of the first device for impedance transforming and the first contact of the second device for impedance transforming. The second device for switching has a second contact connected to signal ground. In several exemplary embodiments, a second resonance circuit is additionally interposed between the antenna and the first device for impedance transforming.
A signal received by the second receiving circuit from the antenna passes first through the device for matching and then through a third device for filtering. In this embodiment, the third device for filtering has a first and a second contact. The first contact of the third device for filtering is connected to the connection point located between the second transmitting circuit, the second receiving circuit and the first contact of the device for matching. The second contact of the third device for filtering is connected to the second receiving circuit. The third device for filtering in this embodiment has a high reflection coefficient at the first contact of the third device for filtering at least for signals transmitted from the second transmitting circuit.
According to other exemplary embodiments, a method is provided for combining signals in a signal combining device for a dual band radio having an antenna. The signal combining device for a dual band radio comprises a first and second transmitting circuits and a first and second receiving circuits connected to a device for matching, which, in turn, is connected to the antenna. A digital signal is transmitted from the first transmitting circuit and received by the second receiving circuit, and an analogue or a digital signal is transmitted from the second transmitting circuit and received by the second receiving circuit. There is a band-separation between the frequencies of the digital signal that the first transmitting circuit is designed to transmit and the analogue (or digital) signal that the second transmitting circuit is designed to transmit. There is also a band-separation between the frequencies that the first receiving circuit and the second receiving circuit are designed to receive.
According to a
Fagerström Karl-Johan
Kunkel Lars Peter
Aoki Makoto
Burns Doane Swecker & Mathis L.L.P.
Chang Vivian
Telefonaktiebolaget LM Ericsson (publ)
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