JP3501782B2 - Mobile phone - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone capable of preventing deterioration of communication quality due to approach or contact of a human body.

[0002]

2. Description of the Related Art In a code division multiplex type mobile phone having a built-in antenna such as a pattern antenna, generally, when a human body approaches or contacts the antenna, the antenna impedance changes, and the gain of the antenna changes accordingly. Communication quality sometimes deteriorated. Therefore, in order to solve the problem of the change in antenna impedance due to the human body approaching or contacting the antenna, the human body approaches or contacts the antenna by switching the matching circuit that performs impedance matching between the transmitting and receiving circuit and the antenna. Even so, there has been proposed a mobile phone capable of obtaining an optimum impedance matching (for example, Japanese Patent Laid-Open No. 2000-2000).
-286924, JP 2001-0777719 A, JP 11-145852 A).

[0003]

However, in a mobile phone in which the impedance between the transmission / reception circuit and the antenna is matched by switching the matching circuit, a special matching circuit such as a plurality of matching circuits and a switching circuit for switching the plurality of matching circuits is used. There was a problem that a different circuit was required.
The present invention has been made to solve the above problems,
An object of the present invention is to provide a mobile phone capable of preventing deterioration of communication quality due to approach or contact of a human body while suppressing an increase in the number of parts.

[0004]

According to the present invention, in a code division multiplex type mobile phone having a pattern antenna built therein, the transmission section (100) for transmitting a transmission signal to the pattern antenna (11) is provided. A driver (104) capable of adjusting the level of a transmission signal, a transmission signal for a pattern antenna output from the transmission unit, and a return signal generated by reflection due to collapse of antenna impedance at the pattern antenna To the circulator (108), a transmission power detection unit (109) that detects whether the transmission power level of the transmission unit is equal to or higher than a predetermined value, and a level of the return signal extracted by the circulator that is equal to or higher than a set value. A return detection unit (110) for detecting, and the transmission power level is less than a predetermined value and And a control unit (12) for controlling the driver so that the level of the transmission signal rises when the level of the transmission signal is equal to or higher than a set value, the level of the transmission signal to compensate for the loss due to the return signal. Is controlled. In one configuration example of the mobile phone of the present invention, the control unit stops the level control of the transmission signal when the transmission power level becomes equal to or higher than a predetermined value. Further, in one configuration example of the mobile phone of the present invention, the control unit outputs an alarm when the transmission power level is lower than a predetermined value and the level of the return signal is equal to or higher than a set value. When the level of the return signal is equal to or higher than the set value after the elapse of a predetermined time, the level of the transmission signal is controlled.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 (a) is an external view of a code division multiplexing mobile phone according to an embodiment of the present invention, FIG. 1 (b).
FIG. 2 is a block diagram showing an internal configuration of the mobile phone of FIG. FIG. 1A shows a user holding the mobile phone 1 in his hand. The mobile phone 1 generates a transmission high frequency signal based on a voice signal or a data signal to be transmitted, transmits a radio frequency signal that demodulates a reception high frequency signal to extract a voice signal or a data signal, and transmits the transmission high frequency signal, It includes a pattern antenna 11 for receiving a received high frequency signal, and a control unit 12 for controlling the entire mobile phone.

FIG. 2 is a block diagram showing the internal structure of the radio section 10. The radio unit 10 generates a transmission high frequency signal based on a voice signal or a data signal to be transmitted.
And an oscillation (SYNTH) unit 20 for generating a local oscillation signal.
0 and a receiving unit 3 for demodulating the received high frequency signal received by the pattern antenna 11 and extracting a voice signal and a data signal.
00 and a transmission high frequency signal output from the transmission unit 100 to the pattern antenna 11 and a reception high frequency signal received by the pattern antenna 11 to the reception unit 300.

The transmitter 100 is a modulator IC which generates a transmission intermediate frequency signal based on a voice signal and a data signal.
(MOD_IC) 101, a mixer 102 that mixes a transmission intermediate frequency signal and a local oscillation signal from the oscillation unit 200 to generate a transmission high frequency signal, and a signal output from the mixer 102 is band-limited to pass the transmission high frequency signal. A filter 103, a driver 104 capable of adjusting the level of a transmission high frequency signal according to a control voltage, and a driver 1
04, a voltage control unit 105 that outputs a control voltage,
A filter 106 that limits the output signal of the driver 104 to pass a transmission high frequency signal, a power amplifier (PA) 107 that amplifies the output signal of the filter 106, a circulator 108, and a transmission power level of the transmission unit 100 have a predetermined value. Transmission power detection unit 109 for detecting whether or not the above
A return detection unit 110 for detecting whether or not the level of a reflected signal (hereinafter referred to as a return signal) from the pattern antenna 11 caused by impedance mismatch between the pattern antenna 11 and the transmission unit 100 is equal to or higher than a set value; It has a hysteresis circuit 111 for accurately sending the detection result of the detection unit 110 to the control unit 12.

The circulator 108 receives the transmission high frequency signal from the PA 107, which is input to the port P1, from the port P2.
Output to the pattern antenna 11 side to prevent the received signal from flowing to the transmitting unit 100. Further, when the impedance of the pattern antenna 11 collapses and the return signal from the pattern antenna 11 is input to the port P2, the circulator 108 outputs this return signal to the port P3 and sends it to the return detection unit 110.

The return detection section 110 and the hysteresis circuit 111, which are the features of the present invention, will be described with reference to FIG. The return detection unit 110 includes a comparator A1, a diode D1, resistors R1 to R3, a semi-fixed resistor R4, and a capacitor C1. The hysteresis circuit 111 includes a comparator A2 and resistors R5 to R8.

In the return detector 110, the diode D
The output of the circulator 108 detected by 1 is applied to the non-inverting input terminal of the comparator A1. On the other hand, the power supply voltage VCC to which the output of the circulator 108 is added through the resistor R2 is divided by the resistors R3 and R4,
This divided voltage is input to the inverting input terminal of the comparator A1 as a threshold voltage.

When the detection output level of the diode D1 input to the non-inverting input terminal is higher than the threshold voltage input to the inverting input terminal, the comparator A1 outputs "H" level and the detection output level is detected. When the voltage is equal to or lower than the threshold voltage, "L" level is output. The hysteresis circuit 111, which has a hysteresis in the input / output characteristics, includes a comparator A
The output of 1 is shaped, stabilized, and sent to the control unit 12.

Next, the function of each part of this embodiment will be described. When the user holds the vicinity of the pattern antenna of the mobile phone 1 in his or her hand as shown in FIG. 1A, the antenna impedance collapses due to the influence of the human body and reflection occurs at the pattern antenna 11 to return the transmission signal to the circulator 10.
Returning to 8, it is possible that good signal transmission cannot be performed.

Therefore, during communication, the transmission power detection unit 109 determines whether the transmission power level of the transmission unit 100 is a predetermined value or more.
If the transmission power level is less than the specified value,
Based on the output of the return detection unit 110, it is determined whether the level of the return signal is equal to or higher than the set value, and if the level of the return signal is equal to or higher than the set value, an alarm message is output. As the warning message at this time, it is conceivable to call the user's attention by using a message such as "grip the upper part of the phone" so that the user's hand moves away from the pattern antenna 11 in the mobile phone. .

After a lapse of a predetermined time from the output of the warning message,
The output of the message is stopped, it is determined again based on the output of the return detection unit 110 whether the level of the return signal is the set value or more, and if the level of the return signal is the set value or more, the transmission power level is increased. That is, a command for increasing the output level of the driver 104 is sent from the control unit 12 to the voltage control unit 105, and control is performed to compensate for the loss of the transmission high frequency signal due to the return signal. In this way, a good communication state can be maintained.

The transmission power control of this embodiment will be described in more detail below with reference to FIG. In the call state, the transmission power detection unit 109 of the transmission unit 100 detects whether the transmission power level is equal to or higher than a predetermined value. The detection result of the transmission power detection unit 109 is transmitted to the control unit 12. When the transmission power level is equal to or higher than the predetermined value (NO in step S1 of FIG. 4), CPU 500 of control unit 12 maintains the call state as it is (step S2).

On the other hand, the detection result of the return detector 110 is transmitted to the controller 12 through the hysteresis circuit 111. The CPU 500 of the control unit 12 uses the hysteresis circuit 1
When the output of 11 is the "H" level, the level of the return signal is considered to be equal to or higher than the set value. When the transmission power level is less than the predetermined value and the level of the return signal is less than the set value (NO in step S3), CPU 500 maintains the call state as it is (step S4).

When the level of the return signal is equal to or higher than the set value in step S3, the CPU 500 causes the speaker (not shown) to output an alarm message (step S3).
5). After a predetermined time has passed, the CPU 500 stops the output of the warning message. Next, the CPU 500 checks the output of the hysteresis circuit 111 again to determine whether the level of the return signal is equal to or higher than the set value (step S).
6).

When the level of the return signal is less than the set value (NO in step S6), CPU 500 maintains the call state as it is (step S7). Here, the reason why the level of the return signal is inspected again after a lapse of a predetermined time from the output of the warning message is that the user expects to change the way of holding the mobile phone 1 according to the warning message. That is, when the level of the return signal becomes less than the set value in step S6, it means that the user has changed the way of holding the mobile phone 1.

If the level of the return signal is equal to or higher than the set value in step S6, it means that the user has not changed the way of holding, or the return loss is large even if the user changes the way of holding. In this case, CPU500
Sends a command signal for increasing the output level of the driver 104 to the voltage controller 105. The voltage control unit 105 uses the CP
The control voltage is changed so that the output level of the driver 104 rises according to the command signal from U500. As a result, the output level of the driver 104 rises (step S8).

After changing the output level of the driver 104, the CPU 500 checks the output of the transmission power detection unit 109 again to determine whether the transmission power level is a predetermined value or more (step S9). If the transmission power level is less than the predetermined value (YES in step S9), CPU5
00 returns to step S3. If the transmission power level is equal to or higher than the predetermined value, the CPU 500 maintains the call state as it is (step S10). Since the process of step S1 is performed at regular intervals, steps S2, S4, S
If the process proceeds to step S7, step S
The process 1 is performed again.

If the user does not change the way of holding despite the warning message is output, or if the return loss is large even if the user changes the way of holding, the level of the return signal remains above the set value. Therefore, if the determination is made using only the return signal, the transmission power level will continue to increase. Therefore, in order to stop the output level control of the driver 104 when the transmission power level becomes equal to or higher than the predetermined value, the determination in step S9 is performed.

[0022]

According to the present invention, when the transmission power level is less than the predetermined value and the level of the return signal is equal to or higher than the set value, the driver is controlled so that the level of the transmission signal rises. Can make up for the loss,
A good communication state can be maintained. As the driver and the control unit, those conventionally mounted on the mobile phone can be used. Further, the transmission power detection unit and the return detection unit are necessary circuits in the conventional mobile phone that matches the impedance between the transmission / reception circuit and the antenna by switching the matching circuit. Therefore, according to the present invention, it is possible to prevent the deterioration of the communication quality due to the approach or contact of the human body while suppressing the increase in the number of parts as compared with the conventional mobile phone.

If the transmission power level is less than the predetermined value and the level of the return signal is equal to or higher than the set value, an alarm is output, and if the level of the return signal is equal to or higher than the set value after a lapse of a predetermined time from the alarm output, By performing the level control of the transmission signal, it is possible to notify the user that the transmission power level has decreased and prompt the user to change the way of holding the mobile phone.

[Brief description of drawings]

FIG. 1 is an external view and a block diagram of a code division multiplexing mobile phone according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a wireless unit according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing configurations of a return detection unit and a hysteresis circuit according to the embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the mobile phone according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mobile phone, 10 ... Radio part, 11 ... Pattern antenna, 12 ... Control part, 100 ... Transmission part, 101 ... Modulator IC, 102 ... Mixer, 103, 106 ... Filter, 104 ... Driver, 105 ... Voltage control part, 107 ...
Power amplifier, 108 ... Circulator, 109 ... Transmission power detection unit, 110 ... Return detection unit, 111 ... Hysteresis circuit, 200 ... Oscillation unit, 300 ... Reception unit, 400
… Duplexer.

Continuation of the front page (56) Reference JP-A-11-274918 (JP, A) JP-A-1-84924 (JP, A) JP-A-11-284522 (JP, A) JP-A-7-212256 (JP , A) JP-A-6-268538 (JP, A) JP-A-2000-353911 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 1/04 H04B 7/26 H04M 1 / 00 H04M 1/725

Claims (3)

(57) [Claims] 1. A code division multiplexing mobile phone having a built-in pattern antenna, comprising a driver, which is provided in a transmission section for transmitting a transmission signal to the pattern antenna, and is capable of adjusting the level of the transmission signal, A circulator in which the transmission signal output from the transmission unit for the pattern antenna and the return signal generated by reflection due to the collapse of the antenna impedance in the pattern antenna flow to one terminal, and whether the transmission power level of the transmission unit is a predetermined value or more. And a return detection unit for detecting whether the level of the return signal extracted by the circulator is equal to or higher than a set value, the transmission power level is less than a predetermined value, and the level of the return signal is If the value is higher than the set value, And a controller for controlling the driver, the mobile phone and controlling the level of said transmission signal to compensate for the loss due to the return signal. 2. The mobile phone according to claim 1, wherein the control unit stops the level control of the transmission signal when the transmission power level reaches or exceeds a predetermined value. 3. The mobile phone according to claim 1, wherein the control unit outputs an alarm when the transmission power level is less than a predetermined value and the level of the return signal is equal to or more than a set value, and the alarm output When the level of the return signal is equal to or higher than a set value after a predetermined time has passed, the mobile phone is characterized in that the level of the transmission signal is controlled.