Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1998-09-29
2002-10-01
Urban, Edward F. (Department: 2685)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S575100, C455S574000
Reexamination Certificate
active
06459915
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a portable cellular phone and an external adapter which is used for a portable cellular phone.
2. Description of the Background Art
In a conventional portable cellular phone
601
, as shown in
FIG. 6
, a transmit signal is radiated from a portable cellular phone transmitting antenna
604
through a portable cellular phone transmit amplifier
602
and a portable cellular phone transmit filter
603
, and a receive signal is received at a portable cellular phone receiving antenna
605
and thereafter supplied to a portable cellular phone receive amplifier
607
through a portable cellular phone receive filter
606
. A transmit switch
608
is disposed between the portable cellular phone transmit filter
603
and the portable cellular phone transmitting antenna
604
, and is connected to an external transmitting antenna
609
as well. Further, a receive switch
610
is disposed between the portable cellular phone receiving antenna
605
and the portable cellular phone receive filter
606
, and is connected to an external receiving antenna
611
as well.
Japanese Patent Application Laid-Open Gazette No. 5-347584 discloses a conventional portable cellular phone and an external adapter for a portable cellular phone. As shown in
FIG. 7
, a transmit signal which is modulated by a modulation part
702
in a portable cellular phone
701
is switched to an intermediate frequency signal line
704
by an intermediate frequency switch relay
703
and transmitted to an on-vehicle booster
706
through a coaxial cable
705
, and the intermediate frequency transmit signal which is transmitted to the on-vehicle booster
706
is converted into a transmit frequency by a voltage control oscillator (VCO)
707
and a transmit mixer
708
. A receive signal which is received by the on-vehicle booster
706
is converted into an intermediate frequency by the voltage control oscillator (VCO)
707
and a receive mixer
709
, transmitted through the coaxial cable
705
and the intermediate frequency signal line
704
, and switched to a demodulation part
710
by the intermediate frequency switch relay
703
.
In the conventional portable cellular phone
601
, where the external transmitting antenna
609
and the external receiving antenna
611
are used, a signal is transmitted and received through the transmit switch
608
, which is disposed between the portable cellular phone transmitting antenna
604
and the portable cellular phone transmit filter
603
, and the receive switch
610
which is disposed between the portable cellular phone receiving antenna
605
and the portable cellular phone receive filter
606
.
However, since the transmit switch
608
is disposed after the portable cellular phone transmit amplifier
602
which uses a loss which is created at the transmit switch
608
, an output power of the portable cellular phone transmit amplifier
602
must be high. Further, since the receive switch
610
is disposed before the portable cellular phone receive amplifier
607
, a Noise Figure (NF) of a receiving system deteriorates. In a satellite communication system or the like which demands transmitting with a high output power and receiving with a high sensitivity, in particular, where the external transmitting antenna
609
and the external receiving antenna
611
are to be used, a high output power of the portable cellular phone transmit amplifier
602
and a low NF of a receiving system are a problem to be solved.
In addition, in the conventional portable cellular phone and an external adapter for the same, as shown in
FIG. 7
, the transmit signal is transmitted in the intermediate frequency band from the portable cellular phone
701
to the on-vehicle booster
706
.
However, it is necessary to convert the transmit signal of the intermediate frequency band into the transmit frequency by the voltage control oscillator (VCO)
707
and the transmit mixer
708
which are disposed in the on-vehicle booster
706
, which inconveniently increases the size of the on-vehicle booster.
SUMMARY OF THE INVENTION
The present invention, to solve the current problem as described above, aims at providing a portable cellular phone and an external adapter for the same, with which it is possible to suppress an increase in an output power of a portable cellular phone transmit amplifier due to a loss at a transmit switch associated with use of an external transmitting antenna, to reduce a deterioration of an NF of a receiving system due to a loss at a receive switch associated with use of an external receiving antenna, and to minimize an increase in the size of an external adapter.
A portable cellular phone according to a first aspect of the present invention comprises: a transmitting portion which includes a portable cellular phone transmit amplifier which amplifies a transmit signal and a transmit switch part which is disposed on the input side to the portable cellular phone transmit amplifier so as to switch whether to output the transmit signal to an external adapter or to the portable cellular phone transmit amplifier; and a receiving portion which includes a portable cellular phone receive amplifier which amplifies a receive signal and a receive switch part which is disposed on the output side to the portable cellular phone receive amplifier so as to switch between the receive signal which is amplified and the receive signal which is supplied from an external adapter.
A second aspect of the present invention is directed to a portable cellular phone external adapter which comprises: a transmit amplifier part which includes a transmit amplifier and a transmit filter, the transmit amplifier amplifying the transmit signal which is outputted to outside from the transmit switch part of the portable cellular phone, the transmit filter passing the transmit signal which is amplified; an external transmitting antenna for transmitting a signal which is outputted from the transmit amplifier part; an external receiving antenna; and a receive amplifier part which includes a receive amplifier and a receive filter, the receive amplifier amplifying the receive signal which is received by the external receiving antenna, the receive filter passing the receive signal which is amplified and supplying the receive signal to the receive switch part of the portable cellular phone.
A third aspect of the present invention is directed to a portable cellular phone apparatus which comprises: a portable cellular phone; and a portable cellular phone external adapter, wherein the transmit switch part of the portable cellular phone is connected to an input of the transmit amplifier of the portable cellular phone external adapter, and the receive switch part of the portable cellular phone is connected to an output of the receive amplifier of the portable cellular phone external adapter.
A further aspect of the present invention is directed to a portable cellular phone external adapter which comprises: a transmit amplifier part which amplifies the transmit signal which is outputted to outside from the transmit switch part of the portable cellular phone; a receive amplifier part which includes a receive amplifier and a duplexer, the receive amplifier amplifying the receive signal and outputting the amplified signal to the receive switch part of the portable cellular phone, the duplexer being connected with the output from the transmit amplifier part and an input to the receive amplifier; and an external transmitting/receiving antenna which is connected to the duplexer.
Another aspect of the present invention is directed to a portable cellular phone apparatus which comprises: a portable cellular phone; a transmit amplifier part which amplifies the transmit signal which is outputted to an external adapter from the transmit switch part of the portable cellular phone; a receive amplifier part which includes a receive amplifier and a duplexer, the receive amplifier amplifying the receive signal and outputting the amplified signal to the receive switch part of the
Kosugi Hiroaki
Maegawa Takaaki
Nakamura Hiroyuki
Sakakura Makoto
Takahashi Ken'ichi
Gesesse Tilahun
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia
Urban Edward F.
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