Telecommunications – Transmitter – Measuring – testing – or monitoring of transmitter
Reexamination Certificate
2000-03-24
2003-08-05
Vo, Nguyen T. (Department: 2682)
Telecommunications
Transmitter
Measuring, testing, or monitoring of transmitter
Reexamination Certificate
active
06603960
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transmission output control device and radio equipment including the same, and more specifically, a transmission output control device to control the transmission signal to be emitted from an antenna, and a radio equipment including the same.
2. Description of the Related Art
Generally, in radio equipment such as some cellular phone terminals, the transmission output level of the transmission signal at the terminal is switched in multiple stages or continuously, in response to instructions from a base station, to reduce power consumption or to reduce interference with other terminals.
FIG. 10
is a block diagram illustrating a basic constitution of a transmission part of the cellular phone terminal with circuits for controlling the transmission output as described above. A transmission output control device
50
is provided with a directional coupler
51
and a detector
52
.
A carrier-wave signal generated in an oscillator
53
is converted into the transmission signal through various processing circuits including an amplifier
54
, and inputted to a high output amplifier
55
. The transmission signal amplified by this high output amplifier
55
is inputted to an antenna multicoupler
56
through the directional coupler
51
, and transmitted by an antenna
57
after unwanted signals are removed by the antenna multicoupler
56
. Further, a reception signal received by the antenna
57
is inputted to a reception part Rx after unwanted signals are removed by the antenna multicoupler
56
. The instruction information for controlling the transmission output level of the transmission signal is included in the above-described reception signal from the base station.
The directional coupler
51
comprises a main line
51
-
1
and a sub line
51
-
2
, whereby part of the transmission signal from the high output amplifier
55
is branched, that is, taken out from one end of the sub line
51
-
2
and inputted to the detector
52
. A terminating resistor R
51
is connected to the other end of the sub line
51
-
2
. In the detector
52
, the transmission signal is rectified by a detection diode D
51
, smoothed by a smoothing capacitor C
51
and then, changed into a detection signal by a load resistor R
52
. The detection signal is inputted to a control circuit
58
as the TSSI (Transmitting Signal Strength Indicator) signal corresponding to the transmission output level of the transmission signal actually being transmitted from the antenna
57
.
A control part
59
provides a control signal to the control circuit
58
to indicate a target transmission output level, in response to an instruction from a base station not indicated in the figure. The control circuit
58
generates a feedback (FB) signal in response to the control signal from the control part
59
, having such a value as to reduce the difference between the actual transmission output level as indicated by the TSSI signal and the target transmission output level. The FB signal is outputted to a control terminal Tc which is capable of controlling the high output amplifier
55
in order to set the actual transmission output level.
As described above, a transmission output control system a part of which comprises the transmission output control device
50
forms a feedback loop, and controls the transmission output level so that the actual transmission output level is changed to the target transmission output level as specified by the control part
59
.
Recently in North America, a dual-band type cellular phone terminal which is usable in both the AMPS (Advanced Mobile Phone Services: 800 MHZ) band and the PCS (Personal Communication Services: 1900 MHZ) band has been developed.
FIG. 11
is a block diagram illustrating a basic constitution of a transmission part of the above-described dual-band type cellular phone terminal. A transmission output control device
60
is provided with first and second directional couplers
61
a
,
61
b
and a detector
62
. The transmission output control device
60
constitutes the transmission output control system forming the feedback loop together with first and second high output amplifiers
63
a
,
63
b
, a control circuit
64
and a control part
65
. The operation of the transmission output control system including the transmission output control device
60
is the same as that of the transmission output control system including the transmission output control device
50
of FIG.
10
.
The conventional transmission output control devices described above are formed by respectively mounting discrete parts constituting a directional coupler, a detector and a tuner on a circuit substrate. As a result, the transmission output control device and the entire radio equipment are increased in size.
Further, because the discrete parts constituting the directional coupler, the detector and the tuner of the transmission output control device are connected to each other by wiring provided on the circuit substrate, losses due to the wiring are increased, and there has been a problem that the characteristic of the transmission output control device is degraded.
In addition, in the dual-band equipment, a gap between the two directional couplers must be ensured to obtain isolation between them, and thus, the transmission output control device and the entire radio equipment are further increased in size.
SUMMARY OF THE INVENTION
To overcome the above described problems, embodiments of the present invention provide a compact transmission output control device with excellent characteristics and radio equipment including the same.
One embodiment of the present invention provides a transmission output control device comprising: a directional coupler which branches a part of a transmission signal amplified by a high output amplifier; and a detector which detects a part of said branched transmission signal; wherein said directional coupler and said detector are integrated in a laminated body comprising a plurality of dielectric layers.
According to the above described structure and arrangement, all the wiring of the directional coupler and the detector can be provided inside the laminated body because the directional coupler and the detector which constitute the transmission output control device are integrated within the laminated body. Thus, the loss in each portion of the wiring can be reduced, so that the transmission output control device with excellent characteristic can be obtained.
In the above described transmission output control device, the directional coupler may include a main line and a sub line; the detector may include a detection diode, a smoothing capacitor and a load resistor; the detection diode and the load resistor of the detector may be mounted on the outside of the laminated body; the main line and the sub line of the directional coupler may comprise strip line electrodes provided inside the laminated body; and the smoothing capacitor of the detector may comprise a capacitor electrode and a ground electrode arranged opposite each other on opposite sides of one or more of said dielectric layers inside said laminated body.
According to the above described structure and arrangement, the number of parts of the transmission output control device can be reduced because the main line and the sub line of the directional coupler comprise strip line electrodes provided inside the laminated body, and the smoothing capacitor of the detector comprises the capacitor electrode and the ground electrode provided inside the laminated body. Thus, a compact transmission output control device can be obtained, and the area occupied by the transmission output control device can be reduced in radio equipment in which this transmission output control device is mounted.
In the above described transmission output control device, a plurality of directional couplers may be provided; and the plurality of said directional couplers may be usable for controlling transmission signals of different frequencies and disposed on different ones o
Ishino Satoshi
Kimura Masaki
Nakajima Norio
Oida Toshifumi
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Nguyen David
Vo Nguyen T.
LandOfFree
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