JP2001111466A - Mobile object communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate the receiving electric field levels between two without deteriorating receiving sensitivity when an amplifier is connected between a receiving-only antenna and a change-over switch as to mobile object communication equipment adopting a diversity receiving system. SOLUTION: The mobile object communication equipment adopting the diversity receiving system having at least a transmitting/receiving antenna 11 and a receiving-only antenna and capable of selecting either one of the two antennas on the basis of comparison of receiving electric field levels is provided with the amplifier 1 for amplifying a signal received through the antenna 11 and a detection means 2 for detecting a signal received through the antenna 12 at a level lower than the detection level of the signal received through the antenna 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication apparatus employing a diversity reception system, and more particularly to a control method for a difference in reception electric field level between two antennas.

[0002]

2. Description of the Related Art For example, a mobile communication device such as a mobile phone (hereinafter referred to as a "mobile phone") is known which employs a diversity reception system as a countermeasure against fading. The specific contents of the diversity receiving operation are disclosed in, for example, Japanese Patent Application Laid-Open No. 6-140971, and the outline will be described below with reference to FIG.

FIG. 3 is a block diagram showing a configuration of a receiving system of such a portable telephone. In FIG. 3, the mobile phone includes two antennas, a transmission / reception antenna 11 and a reception-only antenna 12, and a diversity control circuit 13 controls a changeover switch 14 just before a reception timing to connect the transmission / reception antenna 11 to a reception antenna. The reception signal of the dedicated antenna 12 is switched and connected to the reception processing system 15.

[0004] A reception processing system 15 downconverts an input received signal to generate a baseband received signal. The detection circuit 16 detects the baseband reception signal generated by the reception processing system 15 and detects a detection voltage signal (RSSI).
(A voltage signal) to the diversity control circuit 13.

[0005] The diversity control circuit 13 includes a detection circuit 1
Based on the two detected voltage signals from No. 6, the reception electric field levels of the two antennas are compared, and the changeover switch 14 is set to perform the reception operation with the antenna having the high reception electric field level. Thereby, during the reception operation period, the reception signal of the selected antenna is transmitted through the reception processing system 15 to the demodulation circuit 17.
And the original signal is restored.

[0006]

However, since mobile phones often have a built-in receiving-only antenna, there is a difference in the transmission loss between the transmitting / receiving antenna and the receiving-only antenna and the changeover switch. Also, with the progress of miniaturization, the characteristics of the reception-only antenna are strongly affected by the peripheral components and are inferior to those of the transmission / reception antenna.

In such a situation, it is conceivable to provide an amplifier between the reception-only antenna and the changeover switch in order to improve the characteristics of the reception-only antenna. However, this causes a difference in the reception electric field level between the two antennas, so there is a problem how to adjust the reception electric field level difference between the two antennas.

An object of the present invention is to provide a mobile communication apparatus employing a diversity system, in which, when an amplifier is provided between a reception-only antenna and a changeover switch, reception between two antennas is not deteriorated without deteriorating reception sensitivity. It is an object of the present invention to provide a mobile communication device provided with means for controlling an electric field level.

[0009]

According to a first aspect of the present invention, there is provided a mobile communication device having at least two antennas, a transmitting / receiving antenna and a receiving-only antenna. In a mobile communication device that employs a diversity reception system that selects one of the antennas, an amplifier that amplifies a reception signal of the reception-only antenna is provided, and the level is lower than a detection level of a reception signal of the transmission / reception antenna. A detection means for detecting a reception signal of the reception-only antenna is provided.

According to the first aspect of the present invention, even if an amplifier is inserted for the purpose of improving the characteristics of the reception-only antenna, the reception electric field level of the reception-only antenna is lower than that of the transmission / reception antenna. An operation is performed. Therefore, the reception electric field level between the two antennas can be changed without deteriorating the reception sensitivity, and an appropriate antenna can be selected.

A mobile communication device according to a second aspect of the present invention includes a transmission / reception antenna and a reception-only antenna, a first changeover switch for switching a reception signal of the two antennas and outputting the reception signal to a reception processing system, An amplifier provided between the reception-only antenna and the first changeover switch for amplifying a reception signal, a first detection circuit for detecting a reception signal generated by a reception processing system, and a first detection circuit for detecting the reception signal A second detection circuit for detecting at a level lower than a detection level of the circuit by a predetermined value, a second changeover switch for switching and outputting a reception signal generated by a reception processing system to the first and second detection circuits, The first and second changeover switches so that a reception signal of a transmission / reception antenna is input to the first detection circuit and a reception signal of the reception-only antenna is input to the second detection circuit. Synchronously with the switching control, characterized by comprising a diversity control circuit for selecting one of said two antennas based on the magnitude comparison of the detection signal of the first and second detection circuits.

According to the invention described in claim 2, 2
By switching between the two detection circuits, the reception electric field level between the two antennas can be changed.

According to a third aspect of the present invention, there is provided a mobile communication apparatus comprising: a transmission / reception antenna and a reception only antenna; a changeover switch for switching a reception signal of the two antennas to output to a reception processing system; An amplifier provided between an antenna and the first changeover switch for amplifying a reception signal, a detection circuit for detecting a level of a reception signal generated in a reception processing system, and switching control of the changeover switch;
A diversity control circuit for selecting one of the two antennas based on a magnitude comparison of the detection signals of the detection circuit; And a detection level correction circuit for lowering the detection level to a predetermined value.

According to the third aspect of the invention, the reception electric field level between the two antennas can be changed by the detection level correction circuit.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a mobile communication device (reception system) according to a first embodiment of the present invention. Book first
The embodiment corresponds to claims 1 and 2. The same components as those in FIG. 3 are denoted by the same reference numerals and names. Less than,
The description will focus on the portion according to the first embodiment.

Referring to FIG. 1, in the receiving system of the mobile communication apparatus according to the first embodiment, an amplifier 1 is provided between a reception-only antenna 12 and a changeover switch 14, and a detection circuit 2 and a changeover switch 3 are added. And the diversity control circuit 4 controls the switching of the two change-over switches 14 and 3 in synchronization with each other, compares the detection voltage signals of the two detection circuits 16 and 2,
One of the antennas is selected.

The correspondence between the above configuration and the first and second aspects is as follows. For both transmitting and receiving antennas,
The transmitting / receiving antenna 11 corresponds. The reception-only antenna corresponds to the reception-only antenna 12. The amplifier has
The amplifier 1 corresponds. One of the detection circuit 16 and the detection circuit 2 corresponds to the detection means.

The changeover switches 14 and 3 correspond to the first and second changeover switches. The detection circuits 16 and 2 correspond to the first and second detection circuits. The diversity control circuit 4 corresponds to the diversity control circuit.

Next, the operation of the first embodiment will be described with reference to FIG. In FIG. 1, a diversity control circuit 4
Is the switch 1 immediately before the reception timing.
A diversity control signal is sent to the antennas 4 and 3, and the two switches 14 and 3 are synchronized so that the reception signal of the transmission / reception antenna 11 is input to, for example, the detection circuit 16 and the reception signal of the reception-only antenna 12 is input to the detection circuit 2. To switch.

The detection circuit 16 includes the transmitting / receiving antenna 11
, And outputs a detected voltage signal to the diversity control circuit 4. The detection circuit 2 detects a reception signal of the reception antenna 12 and outputs a detection voltage signal to the diversity control circuit 4.

The diversity control circuit 4 compares the detection voltage signals of the two detection circuits 16 and 2 and controls the changeover switch 14 so that one reception signal of the two antennas is connected to the reception processing system 3. I do.

Here, it is assumed that the gain of the amplifier 1 is 10 dB and the reception electric field level of the transmitting / receiving antenna 11 is 18 dB.
When the reception electric field level of the reception-only antenna 12 is 1
It is assumed that it is 0 dBμ. If the detection levels of the two detection circuits 16 and 2 are the same, the detection voltage signal of the detection circuit 2 is larger, so the diversity control circuit 4 controls the changeover switch 14 to select the reception-only antenna 12. .

However, since the receiving sensitivity is not improved by the gain of the amplifier 1, the transmitting / receiving antenna 11 has better receiving sensitivity in the case of the above example. Therefore, this first
In the embodiment, the detection level of the detection circuit 2 is set, for example, by lowering the gain of the amplifier 1. Therefore, in the case of the above example, since the detection voltage signal of the detection circuit 16 is larger, the diversity control circuit 4 controls the changeover switch 14 so as to select the transmitting / receiving antenna 11.

When the detection voltage signal of the detection circuit 2 exceeds the detection voltage signal of the detection circuit 16, the diversity control circuit 4 controls to select the reception-only antenna 12. Since the characteristics of the receiving antenna 12 are improved by the amplifier 1, the receiving operation can be performed without any trouble.
However, since the detection level of the detection circuit 2 is considerably lower than that of the detection circuit 16, the chance of selecting the reception-only antenna 12 is considerably reduced. That is, it can be said that the reception-only antenna 12 is hardly selected.

As described above, the amplifier 1 is connected to the receiving antenna 12.
Is provided, the received electric field level difference between the two antennas can be manipulated without deteriorating the receiving sensitivity.

FIG. 2 is a block diagram showing the configuration of a receiving system of a mobile communication device according to a second embodiment of the present invention. The second embodiment corresponds to claims 1 and 3. Note that FIG.
The same components as those described above are denoted by the same reference numerals and names. Hereinafter, the portion according to the first embodiment will be mainly described.

In FIG. 2, in the receiving system of the mobile communication device according to the second embodiment, the amplifier 1 is provided between the receiving antenna 12 and the changeover switch 14 and the detection circuit 16 is provided.
A transistor 5 is provided between the output terminal and the ground, and the degree of conduction of the transistor 5 is controlled in synchronization with the changeover switch 14 by the diversity control signal of the diversity control circuit 13,
The level of the detection voltage signal of the detection circuit 16 is operated. Note that the transistor 5 is a bipolar transistor or an FET.

The correspondence between the above configuration and claims 1 and 3 is as follows. For both transmitting and receiving antennas,
The transmitting / receiving antenna 11 corresponds. The reception antenna 12 corresponds to the reception-only antenna. The amplifier 1 corresponds to the amplifier. The detection circuit corresponds to the entirety of the detection circuit 16 and the transistor 5.

A changeover switch 14 corresponds to the changeover switch. The detection circuit 16 corresponds to the detection circuit. The diversity control circuit 13 corresponds to the diversity control circuit. The transistor 5 corresponds to the detection level correction circuit.

Next, the operation of the first embodiment will be described with reference to FIG. In FIG. 2, a diversity control circuit 1
3 is a changeover switch 1 immediately before the reception timing.
4, a diversity control signal is sent to the reception processing system 15 by switching the reception signals of the transmission / reception antenna 11 and the reception-only antenna 12.

The detection circuit 16 includes the transmitting / receiving antenna 11
It detects the reception signals of both the reception antenna 12 and the reception antenna 12 and outputs a detection voltage signal to the diversity control circuit 13.

At this time, the transistor 5 is controlled to a non-conductive state by the diversity control signal when the transmission / reception antenna 11 is selected, and the reception-only antenna 1
When 2 is selected, the conduction state is controlled. That is,
When the transmission / reception antenna 11 is selected, the detection voltage signal of the detection circuit 16 is directly input to the diversity control circuit 13.

On the other hand, when the reception-only antenna 11 is selected, the detection voltage signal of the detection circuit 16 is reduced by the gain of the amplifier 1 and input to the diversity control circuit 13 as described in the first embodiment. I do.

Therefore, the diversity control circuit 13
Performs the same selection operation as in the first embodiment,
The same operation and effect as those of the first embodiment can be obtained.

[0036]

As described above, according to the present invention, even if an amplifier is inserted for the purpose of improving the characteristics of a reception-only antenna, the reception electric field level of the reception-only antenna is made smaller than that of the transmission / reception antenna. Is also performed.

Therefore, the reception electric field level between the two antennas can be changed without deteriorating the reception sensitivity, and an appropriate antenna can be selected. Further, since the reception electric field level of the reception-only antenna can be reduced, it is difficult to select the reception-only antenna.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a mobile communication device (receiving system) according to a first embodiment of the present invention.

FIG. 2 is a configuration block diagram of a mobile communication device (receiving system) according to a second embodiment of the present invention.

FIG. 3 is a general configuration block diagram of a receiving system of the mobile communication device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Amplifier 2 Detection circuit 3 Changeover switch 4 Diversity control circuit 5 Transistor 11 Transmitter / receiver antenna 12 Reception only antenna 13 Diversity control circuit 14 Changeover switch 15 Reception processing system 16 Detection circuit 17 Demodulation circuit

Continuation of the front page F term (reference) 5K059 CC03 DD02 DD07 DD12 DD27 EE03 5K067 AA33 BB04 CC24 DD44 GG11 KK03

Claims (3)

[Claims] 1. A mobile communication device that employs a diversity reception system that has at least two antennas, a transmission / reception antenna and a reception-only antenna, and selects one of the two antennas based on a comparison of a reception electric field level. A mobile device comprising: an amplifier for amplifying a reception signal of the reception-only antenna; and a detection unit for detecting a reception signal of the reception-only antenna at a level lower than a detection level of the reception signal of the transmission / reception antenna. Body communication device. 2. A transmission / reception antenna and a reception only antenna, a first changeover switch for switching a reception signal of the two antennas and outputting the signal to a reception processing system, and between the reception only antenna and the first changeover switch. An amplifier for amplifying the reception signal, a first detection circuit for detecting the reception signal generated in the reception processing system, and detection of the reception signal at a level lower than a detection level of the first detection circuit by a predetermined value. A second detection circuit, a second changeover switch for switching and outputting a reception signal generated by a reception processing system to the first and second detection circuits, and a reception signal of the transmission / reception antenna to the first detection circuit. And the reception signal of the reception only antenna is the second reception signal.
The first and second changeover switches are synchronously controlled so as to be inputted to a detection circuit, and one of the two antennas is selected based on a comparison between the magnitudes of detection signals of the first and second detection circuits. A mobile communication device comprising: a diversity control circuit. 3. A transmission / reception antenna and a reception only antenna, a changeover switch for switching a reception signal of the two antennas and outputting the signal to a reception processing system, and provided between the reception only antenna and the first changeover switch. An amplifier for amplifying a reception signal; a detection circuit for detecting a reception signal generated in a reception processing system; and switching control of the changeover switch; and one of the two antennas based on a comparison between the magnitudes of the detection signals of the detection circuit. A diversity control circuit for selecting, and a detection level correction circuit for receiving the switching signal for selecting the reception-only antenna and lowering a level of a detection signal of the detection circuit to a predetermined value when the diversity control circuit receives the switching signal. Mobile communication device.