JP2001186555A - Mobile wireless terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile wireless terminal, that can make improvement of a spurious emission characteristic for digital communication compatible with improvement of an efficiency characteristic in analog communication. SOLUTION: In the case of digital communication, a power supply voltage Vdd of an RF variable power amplifier 6 is fixed to fix the gain of an RF variable power amplifier 6, thereby allowing the RF variable power amplifier 6 to amplify an RF signal in a region that provides a desired spurious emission level, whereas in the case of an analog mode, the power supply voltage Vdd of the RF variable power amplifier 6 is made variable, so that the RF variable power amplifier 6 amplifies an RF signal in a region, where the characteristic of efficiency η of the RF variable power amplifier 6 is best.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual mode wireless communication apparatus such as an automobile telephone apparatus or a portable telephone apparatus, which selectively uses an analog mode and a digital mode as a communication mode with a base station. .

[0002]

2. Description of the Related Art FIG. 8 shows a configuration of a transmission signal amplifying unit in a conventional dual mode radio communication apparatus. A baseband signal generated by a baseband signal processing unit (not shown) is supplied to an IF band oscillator 2 by a modulator 21.
2 is used as a signal for modulating the IF signal generated by the IF-AG.
The signal is amplified by the C amplifier 23.

The IF amplified by the IF-AGC amplifier 23
The modulated signal is converted into a high-frequency band RF signal by the up-converter 24, and an unnecessary frequency component is removed by the band-pass filter 25.

[0004] Further, the RF signal passed through the band-pass filter 25 is power-amplified by an RF power amplifier 26, and unnecessary frequency components are removed by an antenna duplexer 27 which shares an antenna for transmission and reception. 28
Radiated more into space.

The RF signal power-amplified by the RF power amplifier 26 is converted into a DC signal corresponding to the power by a power detector (DET) 29, and is converted into an A / D converter (AD).
C) and is converted to a digital signal corresponding to the voltage value.

[0006] The digital signal is input to the CPU 32. The CPU 32 outputs data designating the gain of the IF-AGC amplifier 23 to a D / A converter (DAC) 34 according to the value indicated by the digital signal.

The D / A converter 34 generates an analog signal having a voltage value corresponding to the data based on the data, and inputs the analog signal to the IF-AGC amplifier 23 as a gain control signal.

With such a configuration, in the conventional configuration, the RF power amplifier 26 similarly controls the transmission signal to have a desired power in each mode in the digital mode and the analog mode. are doing.

The RF power amplifier 26 is set to have an output characteristic as shown in FIG. 9 with respect to the power level of the input signal. That is, in the digital mode, the output characteristic of the RF power amplifier 26 is linearized in a region up to the maximum power level Pd of the output signal required in this mode, and the RF signal is called a spurious emission level (SEL). The distortion characteristics of the power amplifier 26 are set to be good.

Further, in the analog mode, a power level Pa higher than the maximum power level Pd in the digital mode by a predetermined power is required as the maximum power level of the output signal in comparison with the digital mode. Although the characteristics are not the best, the output characteristics of the RF power amplifier 26 are not necessarily required to be linear because the requirements are not high.

However, looking at the efficiency η characteristic of the RF power amplifier 26 as shown in FIG. 10, the RF power amplifier 26 does not function at the best efficiency in the analog mode.

In the analog mode, the power consumption is larger than that in the digital mode. Therefore, if such a power loss is large, the temperature inside the device increases, and the operation time is shortened.

For this reason, when the output characteristic is changed as shown by a broken line in FIG. 9 so as to exhibit the best efficiency characteristic in the analog mode, the characteristic is changed in the operation region in the digital mode. There is a problem that the linearity is lost and the spurious emission characteristics are at an unsatisfactory level.

[0014]

In the conventional mobile radio terminal, it is difficult for the RF signal power amplifying unit to achieve both improvement in spurious emission characteristics in the digital mode and improvement in efficiency characteristics in the analog mode. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. In an RF signal power amplifying unit, it is possible to achieve both improvement in spurious emission characteristics in digital mode and improvement in efficiency characteristics in analog mode. It is an object of the present invention to provide a possible mobile wireless terminal device.

[0016]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a dual mode wireless communication system for selectively using an analog mode and a digital mode to wirelessly connect to a base station connectable to a network. In the communication device, first amplifying means for amplifying the modulated intermediate frequency transmission signal, up-converting means for converting the intermediate frequency signal amplified by the first amplifying means into a high-frequency signal, A second amplifying means for amplifying the high-frequency signal obtained by the converting means; and in a digital mode, a gain of the first amplifying means is variably controlled so that a transmission signal amplified by the first amplifying means is transmitted. The intensity is set to a predetermined level, and the gain of the second amplifier is fixedly controlled to a predetermined value. On the other hand, in the analog mode, the gain of the first amplifier is fixedly controlled. Both the gain of the second amplifying means is variably controlled, and so the intensity of the high frequency signal amplified by the second amplifying means is constructed by including a gain control means for a predetermined level.

In the mobile radio terminal having the above configuration, to control the transmission power, in the digital mode, the gain of the first amplifier for amplifying the intermediate frequency signal is variably controlled,
The gain of the second amplifying means for amplifying the high-frequency signal is fixedly controlled. On the other hand, in the analog mode, the gain of the first amplifying means is fixedly controlled, and the gain of the second amplifying means is variably controlled. To do it.

Therefore, according to the mobile radio terminal having the above configuration, in the digital mode, the gain is fixed to a place where the spurious emission characteristic of the second amplifier is good, and the gain of the first amplifier is variable. The transmission power is controlled by controlling the transmission power. On the other hand, in the analog mode, the gain of the first amplification means is fixedly controlled, and the transmission power is controlled by variably controlling the gain within a range where the efficiency characteristic of the second amplification means is good. Since the control can be performed, it is possible to achieve both the improvement of the spurious emission characteristic in the digital mode and the improvement of the efficiency characteristic in the analog mode in the second amplifying means.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a mobile wireless terminal device according to the embodiment.

The baseband signal generated by a baseband signal processing unit (not shown) is used as a signal for modulating the IF signal generated by the IF band oscillator 2 by the modulator 1 and is generated by this. The IF modulation signal is IF-
The signal is amplified by the AGC amplifier 3.

The IF-modulated signal amplified by the IF-AGC amplifier 3 is converted into a high-frequency band RF signal by the up-converter 4, and an unnecessary frequency component is removed by the band-pass filter 5.

Further, the RF signal that has passed through the band-pass filter 5 is power-amplified by the RF variable power amplifier 6, and then unnecessary frequency components are removed by the antenna duplexer 7 that shares an antenna for transmission and reception. It is radiated from the antenna 8 into space.

The RF signal power-amplified by the RF variable power amplifier 6 is converted by a power detector (DET) 9 into a DC signal corresponding to the power, and is converted into an A / D converter (AD).
C) and is converted into a digital signal corresponding to the voltage value. This digital signal is input to the CPU 12.

The CPU 12 outputs data designating the gain of the IF-AGC amplifier 3 to a D / A converter (DAC) 14 in accordance with the value indicated by the digital signal, and adjusts the gain of the RF variable power amplifier 6. Specify the data as D
Output to the / A converter (DAC) 13. CPU1
2 controls switching of switches 15 and 16 to be described later according to the communication mode, as shown in FIG.

The D / A converter 14 generates an analog signal having a voltage value corresponding to the data based on the data, and inputs the analog signal to the switch 15. The switch 15 is 2
One input terminal has one of the D / A
An analog signal is input from converter 14, and an analog signal having a predetermined voltage value is input to the other input terminal.

The switch 15 is controlled to be switched by the CPU 12, and one of the analog signals input to the two input terminals is input to the IF-AGC amplifier 3 as a gain control signal.

The DC signal obtained by the power detector 9 is input to one input terminal of a comparator 10. The other input terminal of the comparator 10 is connected to the output terminal of the switch 16.

The comparator 10 compares the reference voltage input from the switch 16 with the voltage of the DC signal obtained by the power detector 9, and determines that the voltage value of the DC signal matches the reference voltage. The gain is varied by controlling the power supply voltage Vdd of the RF variable power amplifier 6.

The switch 16 has two input terminals,
One input terminal receives D / A data from the CPU 12.
The converter 13 converts the analog signal into an analog signal and inputs the analog signal. The remaining input terminal receives an analog signal having a predetermined voltage value. The switch 16 is connected to the CPU 1
2, and one of the analog signals input to the two input terminals is output to the comparator 10.

Next, the operation of the mobile radio terminal having the above configuration will be described below. First, the operation in the digital mode will be described. In the digital mode, the CPU 12
Controls the switch 16 so that an analog signal having a predetermined voltage value as shown by a solid line in FIG. 3A is selectively output to the comparator 10 as a reference voltage.

As a result, the comparator 10 has the switch 16
3 is input as a reference voltage from FIG.
The power supply voltage Vdd of a predetermined voltage value as shown by the solid line in FIG.
Is output to the RF variable power amplifier 6. Therefore, RF
The variable power amplifier 6 is fixed at a predetermined gain.

The CPU 12 sends the analog signal from the D / A converter 14 to the switch 15
Switching control is performed so as to selectively output the gain control signal to the C amplifier 3. As a result, the gain of the IF-AGC amplifier 3 is variably controlled so that the power level detected by the power detector 9 becomes a predetermined value, as shown by the solid line in FIG.

On the other hand, in the analog mode, the CPU 12
Supplies an analog signal having a predetermined voltage value as indicated by a broken line in FIG.
Control is performed so as to be selectively output as a gain control signal to the amplifier 3. Thus, the IF-AGC amplifier 3 is fixed at a predetermined gain because a predetermined voltage is input from the switch 15 as a gain control signal.

The CPU 12 controls the switch 16 to selectively output the analog signal from the D / A converter 13 as a reference voltage to the comparator 10 as shown by the broken line in FIG. I do.

As a result, the RF variable power amplifier 6 sets the power supply voltage Vdd as shown by the broken line in FIG. 3B so that the power level detected by the power detector 9 becomes a predetermined value.
Is variably controlled, and the gain is controlled.

As described above, in the mobile radio terminal having the above configuration, in the digital mode, the power supply voltage Vdd of the RF variable power amplifier 6 is fixed and the RF variable power amplifier 6
And the gain of the IF-AGC amplifier 3 is variably controlled so that the power level detected by the power detector 9 becomes a predetermined value, and the input level of the RF variable power amplifier 6 is changed. Variable.

On the other hand, in the analog mode, IF-A
By fixing the gain of the GC amplifier 3, the input level of the RF variable power amplifier 6 is kept constant, and the power level detected by the power detector 9 is set to a predetermined value. So that the power supply voltage V
dd is variably controlled.

That is, as shown in FIGS. 4 and 5,
In the digital mode, the power supply voltage Vdd of the RF variable power amplifier 6 is fixed and the gain of the RF variable power amplifier 6 is fixed in the same manner as in the related art, so that the RF signal is amplified in a region where a desired spurious emission level is obtained. The operation is performed. On the other hand, in the analog mode, the power supply voltage Vdd of the RF variable power amplifier 6 is changed so that the RF variable power amplifier 6 performs the amplification operation of the RF signal in a region where the efficiency η characteristic is the best. I have to.

Therefore, according to the mobile radio terminal having the above-described configuration, it is possible to achieve both the improvement in the spurious emission characteristics in the digital mode and the improvement in the efficiency η in the analog mode in the RF variable power amplifier 6. .

Next, a mobile radio terminal according to a second embodiment of the present invention will be described. FIG. 6 shows the configuration. However, in FIG. 6, the same components as those in FIG. 1 showing the configuration of the mobile radio terminal device of the first embodiment are denoted by the same reference numerals.

The baseband signal generated by the baseband signal processing unit (not shown) is used by the modulator 1 as a signal for modulating the IF signal generated by the IF band oscillator 2 and generated by this. The IF modulation signal is IF-
The signal is amplified by the AGC amplifier 3.

The IF-modulated signal amplified by the IF-AGC amplifier 3 is converted into a high-frequency band RF signal by the up-converter 4, and an unnecessary frequency component is removed by the band-pass filter 5.

Further, the RF signal that has passed through the band-pass filter 5 is power-amplified by the RF variable power amplifier 6, and unnecessary frequency components are removed by the antenna duplexer 7 that shares an antenna for transmission and reception. It is radiated from the antenna 8 into space.

The RF signal power-amplified by the RF variable power amplifier 6 is converted by a power detector (DET) 9 into a DC signal corresponding to the power, and is converted into an A / D converter (AD).
C) and is converted into a digital signal corresponding to the voltage value. This digital signal is input to the CPU 12.

The CPU 12 outputs data specifying the gain of the IF-AGC amplifier 3 to the limiter (LIMIT) 19 in accordance with the value indicated by the digital signal, and outputs data specifying the gain of the RF variable power amplifier 6. D
Output to the / A converter (DAC) 13.

The CPU 12 controls switches 15 and 16 to be described later in accordance with the communication mode, as shown in FIG. Further, the CPU 12 notifies the limiter 19 of the currently used communication mode.

The D / A converter 14 generates an analog signal having a voltage value corresponding to the data based on the data input from the limiter 19 and inputs the analog signal to the switch 15. The switch 15 has two input terminals, one of which receives an analog signal from the D / A converter 14 and the other of which receives an analog signal having a predetermined voltage value. Is done.

The switch 15 is switched and controlled by the CPU 12, and one of the analog signals input to the two input terminals is input to the IF-AGC amplifier 3 as a gain control signal.

The DC signal obtained by the power detector 9 is input to one input terminal of the comparator 10. The other input terminal of the comparator 10 is connected to the output terminal of the switch 16.

The comparator 10 compares the reference voltage input from the switch 16 with the voltage of the DC signal obtained by the power detector 9, and determines that the voltage value of the DC signal matches the reference voltage. The gain is varied by controlling the power supply voltage Vdd of the RF variable power amplifier 6.

The switch 16 has two input terminals,
One input terminal receives D / A data from the CPU 12.
The converter 13 converts the analog signal into an analog signal and inputs the analog signal. The remaining input terminal receives an analog signal having a predetermined voltage value. The switch 16 is connected to the CPU 1
2, and one of the analog signals input to the two input terminals is output to the comparator 10.

An unnecessary frequency component is removed from the RF signal received through the antenna 8 by the antenna duplexer 7.
It is input to the receiver (RX) 17. The receiver 17 performs a receiving process according to the communication mode, and the signal subjected to the predetermined receiving process is transmitted to an A / D converter (ADC) 1
8 is input.

The A / D converter 18 converts an input signal from an analog signal to a digital signal indicating its power level, and outputs it to a baseband signal processing unit (not shown) and a limiter 19.

The limiter 19 monitors the reception level from the digital signal input from the A / D converter 18, and
It operates according to the type of communication mode notified from U12. In the case of analog mode, the digital signal from CPU 12 is transmitted to D / D regardless of the reception level.
The signal is output to the A converter 14.

In the digital mode, the limiter 19 converts the digital signal from the CPU 12 into a digital signal when the digital signal input from the A / D converter 18 indicates a reception level less than the predetermined value th. A converter 1
4 as it is.

On the other hand, when the digital signal input from the A / D converter 18 indicates a reception level equal to or higher than the predetermined value th, the limiter 19 controls the digital power indicating the predetermined value in order to limit the transmission power. D / A converter 14
To limit the gain of the IF-AGC amplifier 3.

Next, the operation of the mobile radio terminal having the above configuration will be described below. First, the operation in the analog mode will be described. The CPU 12 controls the limiter 19
It notifies that the communication mode is the analog mode, whereby the limiter 19 enters a through state in which the digital signal from the CPU 12 is output to the A / D converter 14 as it is.

The CPU 12 controls the switch 15 to selectively output an analog signal having a predetermined voltage value as shown by a broken line in FIG. 3C to the IF-AGC amplifier 3 as a gain control signal. I do. With this, IF
The -AGC amplifier 3 is fixed at a predetermined gain because a predetermined voltage is input from the switch 15 as a gain control signal.

The CPU 12 controls the switch 16 so as to selectively output the analog signal from the D / A converter 13 as a reference voltage to the comparator 10 as shown by a broken line in FIG. I do.

As a result, the RF variable power amplifier 6 sets the power supply voltage Vdd as shown by the broken line in FIG. 3B so that the power level detected by the power detector 9 becomes a predetermined value.
Is variably controlled, and the gain is controlled.

Next, the operation in the digital mode will be described. In the digital mode, the CPU 12 notifies the limiter 19 that the communication mode is the digital mode.
The switching control is performed so that an analog signal having a predetermined voltage value as shown by a solid line is selectively output to the comparator 10 as a reference voltage.

As a result, the comparator 10 has the switch 16
3 is input as a reference voltage from FIG.
The power supply voltage Vdd of a predetermined voltage value as shown by the solid line in FIG.
Is output to the RF variable power amplifier 6. Therefore, RF
The variable power amplifier 6 is fixed at a predetermined gain.

The CPU 12 sends the analog signal from the D / A converter 14 to the switch 15 through the IF-AG
Switching control is performed so as to selectively output the gain control signal to the C amplifier 3.

When the digital signal input from the A / D converter 18 indicates a reception level lower than a predetermined value, the limiter 19 converts the digital signal from the CPU 12 into a D / A signal.
The data is output to the converter 14 as it is.

On the other hand, if the digital signal input from A / D converter 18 indicates a reception level equal to or higher than a predetermined value, limiter 19 sets a limit on the transmission power.
A digital signal indicating a predetermined value is output to the D / A converter 14 to limit the gain of the IF-AGC amplifier 3.

The IF-AGC amplifier 3 changes the power level detected by the power detector 9 to a predetermined value, as shown by the solid line in FIG. 3C, except when the gain is limited by the limiter 19. The gain is variably controlled so that

As described above, the mobile radio terminal having the above configuration is suitable for controlling the transmission power according to the distance from the base station as in the CDMA (Code Division Multiple Access) system. As shown by the solid line of 7,
When using in the digital (CDMA) mode, if the intensity of the signal received from the base station is less than the predetermined value th, the maximum gain value of the IF-AGC amplifier 3 is limited to limit the transmission power. I have. Note that the alternate long and short dash line in FIG. 7 indicates the characteristic in the analog mode.

Therefore, according to the mobile radio terminal having the above configuration, the present invention can be applied to the case where the transmission power is controlled according to the distance from the base station as in the CDMA system.
In the F variable power amplifier 6, the spurious emission characteristics in the digital mode can be improved and the efficiency η in the analog mode can be improved at the same time, and the transmission power in the digital mode can be controlled.

The present invention is not limited to the above embodiment. It goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0070]

As described above, according to the present invention, in the digital mode, the gain of the first amplifying means for amplifying the intermediate frequency signal is variably controlled in the digital mode to amplify the high frequency signal. In the analog mode, the gain of the second amplifying means is fixedly controlled and the gain of the second amplifying means is variably controlled. ing.

Therefore, according to the present invention, in the digital mode, the gain is fixed at a place where the spurious emission characteristic of the second amplifying means is good, and the gain of the first amplifying means is variably controlled to transmit power. Control, while
In the analog mode, the transmission power can be controlled by fixedly controlling the gain of the first amplifying means and variably controlling the gain in a range where the efficiency characteristic of the second amplifying means is good. It is possible to provide a mobile radio terminal device capable of achieving both improvement in spurious emission characteristics in the digital mode and improvement in efficiency characteristics in the analog mode.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a first embodiment of a mobile wireless terminal device according to the present invention.

FIG. 2 is a view for explaining switch switching control by a CPU of the mobile wireless terminal device shown in FIG. 1;

FIG. 3 is a view for explaining a gain control operation of an amplifier in the mobile wireless terminal device shown in FIG. 1;

FIG. 4 is a diagram for explaining a gain control operation of an amplifier in the mobile wireless terminal device shown in FIG.

FIG. 5 is a diagram for explaining a gain control operation of an amplifier in the mobile wireless terminal device shown in FIG. 1;

FIG. 6 is a circuit block diagram showing a configuration of a second embodiment of the mobile wireless terminal device according to the present invention.

FIG. 7 is a diagram for explaining the gain control operation of the amplifier in the mobile wireless terminal device shown in FIG. 6;

FIG. 8 is a circuit block diagram showing a configuration of a conventional mobile wireless terminal device.

FIG. 9 is a diagram for explaining the gain control operation of the amplifier in the mobile wireless terminal device shown in FIG.

FIG. 10 is a diagram for explaining the gain control operation of the amplifier in the mobile wireless terminal device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Modulator 2 ... IF band oscillator 3 ... IF-AGC amplifier 4 ... Up-converter 5 ... Band pass filter 6 ... RF variable power amplifier 7 ... Antenna duplexer 8 ... Antenna 9 ... Power detector (DET) 10 ... Comparator 11, 18: A / D converter (ADC) 12: CPU 13, 14, D / A converter (DAC) 15, 16: Switch 17: Receiver 19: Limiter

Claims (4)

[Claims] 1. A dual mode wireless communication apparatus for selectively using an analog mode and a digital mode for wirelessly connecting to a base station connectable to a network, wherein a first signal for amplifying a modulated intermediate frequency transmission signal is provided. An up-converting means for converting the intermediate frequency signal amplified by the first amplifying means into a high-frequency signal; and a second amplifying means for amplifying the high-frequency signal obtained by the up-converting means. In the digital mode, the gain of the first amplifying means is variably controlled so that the intensity of the transmission signal amplified by the first amplifying means is at a predetermined level, and The gain of the means is fixedly controlled to a predetermined value. On the other hand, in the analog mode, the gain of the first amplifying means is fixedly controlled and the second amplifying means is controlled. And the gain is variably controlled, dual-mode radio communication apparatus characterized by comprising the intensity of the high-frequency signal to be amplified and gain control means for a predetermined level by the second amplifying means. 2. The signal processing apparatus according to claim 1, wherein said gain control means includes: a signal strength detection means for detecting a strength level of the high-frequency signal amplified by said second amplification means; a strength level detected by said signal strength detection means; Comparing means for comparing the levels, wherein in the analog mode, the reference level is set to a desired level, and the gain of the second amplifying means is adjusted so that the comparison result of the comparing means becomes a predetermined value. The dual mode wireless communication device according to claim 1, wherein the dual mode wireless communication device performs control. 3. A reception signal strength detection means for detecting a strength of a signal received from the base station, wherein the gain control means, in the digital mode, according to a detection result of the reception signal strength detection means. , The first
2. The dual mode wireless communication apparatus according to claim 1, wherein the gain of said amplifying means is variably controlled. 4. In the digital mode, the gain control means fixes the gain of the first amplifying means to a predetermined value when a detection result of the received signal strength detecting means is less than a predetermined level. The dual-mode wireless communication device according to claim 3, wherein the control is performed to limit the intensity of the transmitted high-frequency signal.