Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1998-12-21
2001-09-25
Bost, Dwayne (Department: 2681)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S550100, C455S575100, C343S702000, C343S841000
Reexamination Certificate
active
06295462
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a portable radio information terminal that has a radio communication function (radio section) and an information processing function (information processing section), and particularly to an antenna configuration for portable radio information terminals.
Conventionally, the portable radio information terminal of that type has the disadvantage in that noises radiated via an antenna from the information processing section adversely affect the radio section, particularly the receiving system, thus deteriorating the radio characteristics, particularly, the S/N ratio of a received radio signal (that is, deteriorating the receiving sensitivity).
One approach of solving that problem is to divide the portable radio information terminal into two parts including the main body and the cover. For example, the main body includes the information processing section and a display on the front surface of the main body. The cover is placed on the front surface of the main body and includes the radio section and an antenna. As generally used in the cellular telephones, the antenna selective diversity receiving system may be employed where plural antennas are disposed on the radio section and reception radio signals are received by selecting an antenna with a strong reception field strength.
FIG. 7
is a block diagram illustrating the configuration of a portable radio information terminal employing the above-mentioned technique.
In the portable radio information terminal, the information processing section is built in the main body while the radio section is built in the cover
2
B. The cover
2
B is mechanically coupled to the main body
1
A by means of the shaft
20
such as a hinge shaft. The cover
2
B is opened and closed to the front surface of the main body
1
A by turning around the shaft
20
acting a rotating shaft.
The main body
1
A includes a battery
3
acting as a power source for the information terminal and a control section
4
B that processes information such as data or digital signals to be output from and input to the cover
2
B. In the information terminal, the display
5
disposed on the display section of the main body
1
A displays image information. A pressure sensitive device (e.g. touch panel) is attached on the display
5
. The information processing procedure is performed by inputting the operation signal to the control section
4
B via the input section
6
. Normally, the information processing section consists of the control section
4
B, the display section
5
and the input section
5
, excluding the battery
3
.
The cover
2
B includes two antennas, that is, a whip antenna
7
being a whiplike conductor protruding from the cover
2
B and an inverted-F antenna
9
A disposed on the bottom (back) surface of the cover
2
B. In the cover
2
B, the radio section consists of a transmission section
13
that produces transmission radio signals, an antenna switch
16
that selects a reception radio signal received via the antenna
7
or
9
, a receiving section
11
that converts a selected reception radio signal to a desired frequency and a desired level and then amplifies the converted signal acting as a received signal, a circulator
10
that transmits a transmission radio signal to the switch
16
and transmits a reception radio signal from the switch
16
to the receiving section
11
, and a modulator and demodulator section
12
that modulates data or digital signal from the control section
4
B and then transmits the modulated signal to the transmission section
13
and that demodulates a reception signal from the receiving section
11
and then transmits a digital signal being the demodulated data to the control section
4
B. The demodulation section
12
B includes a radio control section that controls the radio section. The radio control section selectively controls the frequency of a transmission signal and the frequency of a reception signal, controls the level of a radio signal output from the transmission section
13
, and selectively controls the antenna switch
16
. The circulator
10
acts as an isolator that prevents the input and output signals to and from the antenna
7
or
9
from being adversely affected by the receiving section
11
or transmission section
13
not involved in a transmission or receiving operation.
In the cover
2
B, at the time of receiving radio signals, the receiving section
11
amplifies radio signals input from the antenna
7
or
9
via the circulator
10
. Then the modulator and demodulator section
12
B demodulates the amplified signal into a digital signal. The digital signal is output to the control section
4
B of the main body
1
A. At the time of transmitting radio signals, the modulation and demodulation section
12
B modulates a digital signal output from the control section
4
B of the main body
1
A. The transmission section
13
amplifies the modulated signal as a transmission radio signal. Then the antenna
7
radiates the radio signal via the circulator
10
.
The portable radio information terminal, shown in
FIG. 7
, performs the antenna selective diversity reception using two antennas
7
and
9
A. The antenna switch
16
selects the antenna
7
or
9
A to be connected to the receiving section
11
at the time of starting the receiving operation. The modulator and demodulator section
12
B compares the level of a received signal from the receiving section
11
. A desired signal is received by connecting the antenna with a stronger received signal level to the receiving section
11
. Normally, since the receiving operation is changed for the transmission operation in a short period in milliseconds, an antenna with a larger received signal level is selected every changing mode.
Where the package is formed of a main body containing the information processing section and a cover for covering the main body and containing the radio section, the above-mentioned portable radio information terminal has the following disadvantage. That is, although the whip antenna can relatively and easily provide the good antenna gain, the metal portion in the main body disposed close to the whip antenna by closing the cover causes a decrease in the antenna gain. Moreover, when the antenna attached to the cover approaches the information processing section acting as a principal noise source of the main body, noises from the information processing section diffracts to the antenna, so that the receiving section of the radio section cannot stably receive reception radio signals.
In the antenna selective diversity reception using plural antennas, when the coupling between a high-gain antenna and the radio section is relatively strong, the use of the high-gain antenna induces the transmission radio signal diffracted from the high-gain transmission antenna to the receiving section. For that reason, in some cases, the constraint occurs that only the low-gain antenna must be used as a transmission antenna. Therefore even when the high-gain antenna decreases its gain due to the approach to the metal portion, the low-gain antenna is forced to be used for transmission.
In other cases, the antenna selective diversity receiving system where an inverted-F antenna is disposed in addition to the whip antenna may be employed for the portable radio information terminal. However, when the cover is in a closed state, noises (transmission radio signals) propagate from the whip antenna to the receiving section, so that the receiving section erroneously detects strong field strength due to the noises. As a result, the diversity reception cannot be stably performed. In order to judge whether or not the strong field strength results from noises or a desired signal, it may be considered to use the means of judging a received data ratio. However, this approach leads to the prolonged judgment time or complicated configuration.
SUMMARY OF THE INVENTION
The objective of the present invention is to solve the above-mentioned tasks.
The objective of the present invention is to provide a portable radio info
Bost Dwayne
NEC Corporation
West Lewis G.
Young & Thompson
LandOfFree
Portable radio information terminal does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Portable radio information terminal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Portable radio information terminal will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2481030