JP2011205610A - Radio transmitter - Google Patents

Abstract

A wireless communication apparatus that generates a constant output power with respect to a temperature change with a small circuit scale is provided.
A radio transmission apparatus includes a baseband signal level conversion unit that adjusts a level of a baseband signal, a modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal, A high-frequency circuit unit having a variable gain amplifier that amplifies the output signal, and a total correction amount for the transmission level setting value is obtained according to the detected internal temperature of the wireless transmission device, and a fine adjustment amount less than the reference value from the total correction amount And the coarse adjustment amount greater than the reference value, and the gain setting value of the variable gain amplifier is obtained based on the corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value, and based on the fine adjustment amount. A correction calculation unit for obtaining the level correction amount of the baseband signal, adjusts the level of the baseband signal based on the level correction amount, and adjusts the level based on the gain setting value. You have to control the gain of the variable gain amplifier.
[Selection] Figure 1

Description

  The present invention relates to a wireless transmission device.

  The wireless transmission device is mounted on a mobile phone or a portable information terminal. There is a problem in that the transmission power decreases due to the temperature increase in the wireless transmission device during the transmission operation as the size and the density increase. That is, a power amplifier is provided at the final stage of the transmission device, and a transmission signal amplified by the power amplifier is transmitted from the antenna. The transmission power of this power amplifier is reduced due to temperature rise.

  On the other hand, the wireless transmission device is required to receive transmission power information from the base station side, for example, and perform transmission with the designated transmission power. In that case, a decrease in transmission power due to a temperature rise hinders proper communication with the base station.

  In view of this, it has been proposed to provide a variable gain amplifier in the final stage of the transmission device and variably control the gain of the variable gain amplifier in accordance with the internal temperature. There is also known a technique that keeps transmission power constant.

JP 2003-298429 A JP 2005-229535 A Japanese Patent Laid-Open No. 08-191224

  However, if the transmission power fluctuation due to the temperature fluctuation of the power amplifier is compensated by the variable gain amplifier in the previous stage, the dynamic range accuracy of the transmission power cannot be obtained. In addition, it is very difficult to keep track of transmission power that varies with time, and the control method is complicated and it is very difficult to maintain the linearity of the transmission power. In the method of variably controlling the gain of the variable gain amplifier to correct the output power, the circuit scale of the variable gain amplifier must be increased in order to increase the resolution and enable fine power adjustment. For example, in the case of a variable gain amplifier having a configuration in which a plurality of amplification transistors are provided in parallel and an amplification transistor is selected according to a gain control signal, it is desired to increase the number of amplification transistors in order to increase the gain resolution.

  On the other hand, there is a method of correcting the input level of the variable gain amplifier. However, if the input level is increased excessively, the dynamic range of the variable gain amplifier will be exceeded, and it will be difficult to maintain the linearity of the output power. Therefore, in the method of correcting the input level, the temperature range in which the transmission power can be made constant is limited.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wireless transmission apparatus that maintains linearity while maintaining transmission power constant over a wide temperature change.

  A first aspect of the wireless transmission device includes a baseband signal level conversion unit that adjusts the level of the baseband signal, a modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal, A high-frequency circuit unit having a variable gain amplifier that amplifies a high-frequency output signal, and a total correction amount for the transmission level set value is obtained according to the detected internal temperature of the wireless transmitter, and a fine adjustment less than the reference value is obtained from the total correction amount Is calculated based on the corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value and the fine gain correction value. The baseband signal level correction amount to adjust the baseband signal level based on the level correction amount and based on the gain setting value. You have to control the gain of the variable gain amplifier.

  A second aspect of the wireless transmission device includes: a baseband signal level conversion unit that adjusts the level of the baseband signal; a modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal; A total correction amount for the transmission level set value is determined according to the detected internal temperature of the wireless communication device and the frequency of the high-frequency output signal, and a high-frequency circuit unit having a variable gain amplifier that amplifies the high-frequency output signal. Obtain the fine adjustment amount less than the reference value and the coarse adjustment amount greater than the reference value, and obtain the gain setting value of the variable gain amplifier based on the corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value. A correction operation unit for obtaining a level correction amount of the baseband signal based on the fine adjustment amount, and the level of the baseband signal based on the level correction amount. Adjusted to control the gain of the variable gain amplifier based on the gain set value.

  According to the first aspect, it is possible to provide a wireless transmission device that generates a constant transmission power with respect to a temperature change with a small circuit scale.

  According to the second aspect, it is possible to provide a wireless transmission device that generates constant transmission power with respect to temperature change and frequency change with a small circuit scale.

It is a block diagram of the radio | wireless communication apparatus in 1st embodiment. It is a figure which shows the example of a relationship between the gain setting value of a variable gain amplifier, and the output power of a transmitter. It is a figure explaining the correction accompanying the example of a relationship between the gain setting value and output power of FIG. It is a figure which shows the example of a measurement of the change of the output electric power with respect to temperature. It is a figure which shows the structure and characteristic of a baseband signal level conversion part. It is a flowchart figure which shows the correction calculation by the correction calculating part 14 in 1st embodiment, and the correction control of the output electric power by the baseband process part 10 grade | etc.,. It is a figure which shows the relationship between the total correction amount C1 and detected temperature Tsensor. It is a figure which shows the relationship between fine adjustment amount FC and detection temperature Tsensor. It is a figure which shows the relationship between rough adjustment amount RC and detected temperature Tsensor. It is a figure which shows the relationship between correction | amendment transmission level setting value Pset2 and detected temperature Tsensor. It is a figure which shows the example of conversion table 1,2,3. It is a figure which shows the output power TXpower when the output power is corrected by the coarse adjustment amount by the variable gain amplifier in the high frequency circuit. It is a figure which shows output electric power TXpower at the time of correct | amending coarse adjustment amount by the variable gain amplifier in a high frequency circuit, and correct | amending fine adjustment amount by a baseband signal level conversion part. It is a figure which shows the change of the output power with respect to the frequency of a transmission signal. It is a block diagram of the radio | wireless transmitter of 2nd embodiment. It is a figure explaining the calculation method of frequency correction amount Cf. It is a figure which shows the example of the parameter used for calculation of the frequency correction amount Cf. It is a flowchart which shows calculation of the total correction amount C2 by the correction calculating part 14 in 2nd embodiment, and correction control of the output electric power by the calculated | required total correction amount C2. It is a figure which shows the relationship between the total correction amount C2 and detected temperature Tsensor. It is a figure which shows the relationship between fine adjustment amount FC and detection temperature Tsensor. It is a figure which shows the relationship between rough adjustment amount RC and detected temperature Tsensor. It is a figure which shows the relationship between correction | amendment transmission level setting value Pset2 and detected temperature Tsensor. It is a figure which shows the output electric power TXpower with respect to the frequency at the time of performing correction | amendment control in 2nd embodiment.

[First embodiment]
FIG. 1 is a configuration diagram of a wireless communication apparatus according to the first embodiment. The wireless communication apparatus includes a baseband processing unit 10 that generates a baseband signal, a high-frequency circuit unit 20 that generates a high-frequency transmission signal from the baseband signal, and an antenna that transmits the high-frequency transmission signal into the air.

  In the baseband processing unit 10, a baseband signal BBin generated by a digital signal processing circuit (not shown) is converted into an analog signal by a digital / analog converter DAC, and the baseband signal level conversion unit 13 converts the level (amplitude) of the signal. Adjusted according to the corrected baseband level setting value BBset2, and outputs the baseband signal BBout whose level has been adjusted. The high-frequency circuit unit 20 includes a quadrature modulation circuit QMOD that quadrature-modulates the adjusted baseband signal BBout with the local frequency signal FL, and a variable gain amplifier that amplifies the modulated high-frequency signal with a gain corresponding to the gain setting signal Vvga. It has a VGA and a power amplifier PA that amplifies its output.

  The baseband processing unit 10 obtains a total correction amount C1 according to the temperature in the wireless device, and obtains a fine adjustment amount FC less than the reference value and a coarse adjustment amount RC greater than the reference value from the total correction amount C1. A calculation unit 14 is included. Further, the correction calculation unit 14 obtains the gain setting value Gvga of the variable gain amplifier based on the corrected transmission level setting value Pset2 obtained by adding the coarse adjustment amount RC to the transmission level setting value Pset, and based on the fine adjustment amount FC. A baseband level correction amount Cbb is obtained. The correction calculation unit 14 also includes conversion tables 1, 2, and 3.

  As a result, even if the output power of the power amplifier is reduced in accordance with the temperature change, the baseband signal level conversion unit 13 adjusts the level of the fine adjustment amount of the total correction amount corresponding to the reduction amount, and the phase correction amount is calculated. The variable gain amplifier VGA adjusts the level of the coarse adjustment amount obtained by subtracting the fine adjustment amount. As a result, the resolution of the gain of the variable gain amplifier VGA can be reduced to reduce the circuit configuration, and a minute correction amount that cannot be handled by the variable gain amplifier VGA can be adjusted by the baseband signal level conversion unit 13.

  FIG. 2 is a diagram illustrating a relationship example between the gain setting value of the variable gain amplifier and the output power of the transmission device. FIG. 3 shows an example of a result of measuring the output power of the power amplifier PA when the gain setting value Gvga is changed in the transmission device shown in FIG. Increasing the gain setting value Gvga increases the gain of the variable gain amplifier VGA and increases the output power obtained. However, when the detected temperature indicated by the solid line is 30 ° C and when the detected temperature indicated by the broken line is 40 ° C, the output power is different, and when the detected temperature is 40 ° C higher than the reference temperature 30 ° C, Output power is low.

  FIG. 3 is a diagram for explaining the correction associated with the example of the relationship between the gain setting value and the output power in FIG. A table 40 in FIG. 3 shows a transmission level setting value indicating the power to be transmitted from the antenna, a VGA gain setting value Gvga obtained by converting the transmission level setting value by the conversion table 1 in FIG. 1, and a corresponding detection. The relationship with output electric power when temperature is 30 degreeC is shown. The relationship between the VGA gain setting value Gvga and the output power is the same as the solid line in FIG. As described above, the VGA gain setting value Gvga (hexadecimal, HEX) also increases or decreases according to the increase or decrease of the transmission level setting value (dBm), and the output power also increases or decreases accordingly. The detection temperature of 30 ° C. is the reference temperature, and the conversion characteristics of the conversion table 1 are designed so that the output power substantially matches the transmission level setting value at this reference temperature.

  Further, the variable step width of the transmission level setting value is 1.0 dB as shown in the figure.

  On the other hand, when the temperature in the apparatus rises to 40 ° C., the amplification factor of the power amplifier PA decreases, and the output power obtained even with the same VGA gain setting value Gvga decreases as shown in Table 41 of FIG. For example, for the gain setting value Gvga = EC when the transmission level setting value is 21.0 dBm, if the temperature is a reference temperature of 30 ° C., the output power is 21.3 dBm, which is almost equal to the transmission level setting value 21.0 dBm. However, when the temperature rose to 40 ° C, the output power decreased to 19.0 dBm.

  Therefore, it is desirable to correct the transmission level setting value of 21.0 dBm to 23.0 dBm so that output power of 21.2 dBm can be obtained even when the temperature is 40 ° C.

FIG. 4 is a diagram illustrating a measurement example of change in output power with respect to temperature. The solid line is the measured value, and the broken line is the approximate straight line. As shown in FIG. 4, when the characteristics of a certain power amplifier are measured, when the temperature rises for a certain input signal, the output power decreases by a linear function. According to the broken straight line that approximates the actual measured value of the solid line, the slope is -0.2 dB / ° C. Therefore, in this case, the amount to be corrected is 0.2 × dT (dB) for the difference temperature dT (= Td−Tbase, (° C.)) of the measured temperature Td with respect to the reference temperature Tbase (= 30 ° C.). I understand that. That is, 0.2 dB / ° C is a correction coefficient, and the total correction amount C1 is as follows.
Total correction amount C1 = 0.2 x dT = 0.2 x (Td-Tbase) (dB) (1)
This total correction amount C1 is a relative amount indicating how many times the set transmission level Pset (dBm) should be corrected, and its unit is dB. On the other hand, the set transmission level Pset is an absolute amount of output power with respect to 1 mW, and its unit is dBm.

  FIG. 5 is a diagram illustrating the configuration and characteristics of the baseband signal level conversion unit. The baseband signal level conversion unit 13 amplifies the baseband signal BBin and outputs the baseband signal BBout after level adjustment, and the corrected baseband setting value BBset2 to the control voltage Vcnt that controls the gain of the amplifier AMP. A digital-to-analog converter D / A for conversion. The amplifier AMP is a variable gain amplifier, and its gain is variably controlled in accordance with the control voltage Vcnt, whereby the amplitude of the adjusted baseband signal BBout is variably controlled.

  Next, correction amount calculation by the correction calculation unit in the first embodiment will be described. In FIG. 1, the correction calculation unit 14 is a CPU that executes a calculation program, for example, and based on the detected temperature Tsensor detected by the temperature detection circuit 32 and the temperature correction coefficient a stored in the storage unit 30 in advance. The total correction amount C1 is obtained, the fine adjustment amount FC and the coarse adjustment amount RC are obtained from the total correction amount C1, and the coarse adjustment amount RC is added to the transmission level setting value Pset to obtain the corrected transmission level setting value Pset2.

  FIG. 6 is a flowchart showing correction calculation by the correction calculation unit 14 and output power correction control by the baseband processing unit 10 and the like in the first embodiment. The output power correction control in the first embodiment will be described with reference to FIGS. 1 and 6.

  First, the transmission level set value Pset (dBm) is set (S1). The transmission level setting value Pset is information on the transmission level to be set by the terminal side in accordance with, for example, the distance to the base station and the communication state. In FIG. 1, the transmission level set value Pset is input to the correction calculation unit 14.

  Next, the correction calculation unit 14 reads the reference temperature Tbase (° C.) and the temperature correction coefficient a (dB / ° C.) stored in the storage unit 30 (S2, S3). The temperature correction coefficient a is as described in the above equation (1).

Next, the correction calculation unit 14 performs correction control of output power in steps S4 to S11 according to the temperature change (YES in S12). The correction calculation unit 14 reads the detected temperature Tsensor (° C.) measured by the temperature detection circuit 32 (S4), and the total correction amount calculation unit 15 calculates the total correction amount C1 according to the equation (1) (S5). That is, it is as follows.
C1 = a × (Tsensor−Tbase) (dB) (1 ′)
FIG. 7 is a diagram showing the relationship between the total correction amount C1 and the detected temperature Tsensor. FIG. 7 shows the relationship among the total correction amount C1, the detected temperature Tsensor, the reference temperature Tbase, and the temperature correction coefficient a according to the above equation (1 ′). When the detected temperature Tsensor is the reference temperature Tbase, the total correction amount C1 becomes zero, and the total correction amount C1 increases or decreases with a linear function of the temperature correction coefficient a according to the difference between the detected temperature Tsensor and the reference temperature Tbase.

  Next, in the correction calculation unit 14, the fine adjustment amount calculator 16 calculates a fine adjustment amount FC smaller than a reference value (for example, 1.0 dB which is a variable step width of the transmission level setting value) in the total correction amount C1 (S6). . When the reference value is 1.0 dB, the correction amount (dB) after the decimal point of the total correction amount C1 becomes the fine adjustment amount FC. In this calculation, the remainder obtained by dividing the total correction amount C1 by the reference value 1.0 dB is obtained as the fine adjustment amount FC. Further, the coarse adjustment amount calculator 17 obtains a coarse adjustment amount RC that is greater than or equal to the reference value in the total correction amount C1 (S7). Simply RC = C1-FC.

  FIG. 8 is a diagram showing the relationship between the fine adjustment amount FC and the detected temperature Tsensor. Of the total correction amount C1 in FIG. 7, the correction amount after the decimal point is the fine adjustment amount FC. That is, the fine adjustment amount FC is any value between 0 and 1.0 dB.

  FIG. 9 is a diagram showing the relationship between the coarse adjustment amount RC and the detected temperature Tsensor. Of the total correction amount C1 in FIG. 7, the correction amount with the decimal point omitted is the coarse adjustment amount RC. As shown in FIG. 9, the coarse adjustment amount RC becomes a discrete value in increments of 1.0 dB as the detected temperature Tsensor increases.

  Then, in the correction calculation unit 14, the adder 18 adds the coarse adjustment amount RC to the transmission level setting value Pset, which is an ideal value, and obtains a corrected transmission level setting value Pset2 = Pset + RC (dBm) (S8). .

  FIG. 10 is a diagram illustrating the relationship between the corrected transmission level setting value Pset2 and the detected temperature Tsensor. The corrected transmission level setting value Pset2 is a discrete value obtained by adding the transmission level setting value Pset, which is an ideal value, to the coarse adjustment amount RC in FIG.

  Returning to FIG. 6, the baseband processing unit 10 converts the corrected transmission level setting value Pset2 (dBm) obtained by the correction calculation unit 14 into a gain setting value Gvga (HEX) using the conversion table 1 (S9). This conversion table 1 is set in advance based on the characteristics of the variable gain amplifier VGA in the high-frequency circuit unit 20 through experiments.

  Similarly, the corrected transmission level set value Pset2 (dBm) is converted into the baseband level set value BBset (HEX) by the conversion table 2 (S9). This conversion table 2 is also set in advance based on the characteristics of the variable gain amplifier AMP in the baseband signal level conversion unit 13 through experiments.

  Further, the baseband processing unit 10 converts the fine adjustment amount FC (dB) into the baseband level correction amount Cbb (HEX) using the conversion table 3 (S9). This conversion table 3 is also set in advance based on the characteristics of the variable gain amplifier AMP in the baseband signal level conversion unit 13 through experiments.

  FIG. 11 is a diagram illustrating an example of the conversion tables 1, 2, and 3. First, in the conversion table 1, the gain setting value Gvga 69 to FF is associated with the corrected transmission level setting value Pset2 of -40 dBm to 30 dBm. As the expected corrected transmission level setting value Pset2 increases, the gain setting value Gvga also increases, and the gain of the variable gain amplifier VGA of the high-frequency circuit unit 20 increases.

  In the conversion table 2, the baseband level setting value BBset 10 to 12 is associated with the corrected transmission level setting value Pset2 of -40 dBm to 30 dBm. That is, the conversion table 3 is obtained as a result of obtaining the characteristics of the baseband signal level conversion unit 13 through experiments or the like. Even if the corrected transmission level setting value Pset2 changes, the baseband level setting value BBset is Almost no change. The baseband level setting value BBset is a setting value corresponding to the reference gain of the amplifier AMP in the baseband signal level conversion unit 13, and may be a slightly increasing value as shown in FIG. ) However, if the amplifier AMP in the baseband signal level conversion unit 13 has nonlinear characteristics or the variable gain amplifier VGA in the high-frequency circuit unit 20 has nonlinear characteristics, the conversion table 3 is set accordingly. It is desirable to set in advance as shown in FIG.

  In the conversion table 3, the baseband level correction amount Cbb 00 to 09 (HEX) is assigned to the fine adjustment correction amount FC 0.0 to 0.9 dB. The conversion table 3 is a table for obtaining a correction amount for changing the gain of the amplifier AMP in the baseband signal level conversion unit 13 with respect to the fine adjustment amount FC, and the conversion value is larger than that of the conversion table 2. I understand that.

  The conversion table 1 corresponds to the coarse adjustment amount, whereas the conversion table 3 corresponds to the fine adjustment amount. Therefore, the input resolution of both tables is different.

  In the baseband processing unit 10, the adder 19 adds the baseband correction amount Cbb to the baseband set value BBset to generate a corrected baseband set value BBset2 (S10). Then, the corrected baseband set value BBset2 is converted into the control voltage Vcnt of the amplifier AMP in the baseband level conversion unit 13 shown in FIG. 5 and used for level adjustment of the baseband signals BBin and BBout.

  Further, the gain setting value Gvga is converted into a gain setting signal (voltage) Vvga by the DAC, and is set in the variable gain amplifier VGA in the high frequency circuit unit 20 (S11).

  As described above, the coarse transmission correction amount RC (dB) is added to the transmission level setting value Pset (dBm) to obtain the corrected transmission level setting value Pset2, and the gain of the variable gain amplifier VGA in the high-frequency circuit is controlled based on this. Is done. As a result, the output power is corrected by the coarse adjustment amount RC from the output power corresponding to the transmission level set value Pset. Similarly, a corrected baseband level setting value BBset2 obtained by adding the baseband level correction amount Cbb converted from the fine adjustment amount FC to the baseband level setting value BBset converted from the corrected transmission level setting value Pset2 is obtained, and the base The gain of the amplifier AMP of the band signal level conversion unit 13 is controlled. As a result, the output power is further corrected by the fine adjustment amount FC.

  FIG. 12 is a diagram showing the output power TXpower when the output power is corrected by the coarse adjustment amount by the variable gain amplifier in the high frequency circuit. FIG. 12 shows changes in the detected temperature with respect to the elapsed time on the horizontal axis. In this example, the detected temperature Tsensor gradually increases from the reference temperature Tbase and is saturated at a certain temperature. The output power TXpower obtained by correcting the output power with the variable gain amplifier VGA in the high-frequency circuit with the corrected transmission level setting value Pset2 is changed from Pset to Pset + 3.0 in response to such a change in detected temperature. Each time, the power changes between Pset and Pset-1.0.

  FIG. 13 shows the output power TXpower when the coarse adjustment amount is corrected by the variable gain amplifier in the high frequency circuit and the fine adjustment amount is corrected by the baseband signal level converter as in the first embodiment. FIG. Similar to FIG. 12, the detected temperature Tsensor increases with time. Since the fine adjustment amount is corrected by the baseband signal level converter, the output power TXpower is stably controlled in the vicinity of the output power with respect to the ideal transmission level setting value Pset.

  According to the wireless transmission device of the first embodiment described above, fluctuations in output power with respect to temperature changes can be minimized with a small circuit scale.

[Second Embodiment]
Next, a second embodiment will be described. In the second embodiment, in addition to the detected temperature, the total correction amount C2 for the transmission level setting value is obtained according to the frequency of the transmission signal, and the fine correction amount FC less than the reference value and the reference value are calculated from the total correction amount C2. The coarse adjustment amount RC greater than the value is obtained.

  FIG. 14 is a diagram illustrating a change in output power with respect to the frequency of the transmission signal. In a wireless transmission device that transmits signals of a large number of frequencies, output is performed according to the frequency of the transmission signal even though the transmission level setting value Pset is the same due to the frequency characteristics of the power amplifier PA and filter of the high-frequency circuit unit 20. The power changes. Therefore, in the second embodiment, in addition to the temperature correction amount Ct obtained in the first embodiment described above (the same value as the total correction amount C1 in the first embodiment), the second embodiment depends on the frequency of the transmission signal. The obtained frequency correction amount Cf is obtained, and the transmission level set value is corrected by the total correction amount C2, which is the total value of the temperature correction amount Ct and the frequency correction amount Cf.

  FIG. 15 is a configuration diagram of the wireless transmission device according to the second embodiment. In comparison with the wireless transmission device of the first embodiment shown in FIG. 1, the total correction amount calculation unit 150 includes a frequency correction amount calculation unit 151, a temperature correction amount calculation unit 152, and an addition unit 153. The temperature correction amount calculation unit 152 corresponds to the total correction amount calculation unit 15 in the first embodiment shown in FIG. 1, and a temperature correction amount Ct (first embodiment) corresponding to the temperature in the wireless transmission device. Is the same as the total correction amount C1). The total correction amount calculation unit 150 according to the second embodiment obtains a frequency correction amount Cf corresponding to the frequency of the transmission signal in addition to the temperature correction amount Ct, and is added by the addition unit 153 as described below. The total value of the temperature correction amount Ct and the frequency correction amount Cf is obtained as the total correction amount C2.

  Similarly to the first embodiment, the fine adjustment amount calculator 16 of the correction calculator 14 obtains a fine adjustment amount FC less than the reference value from the total correction amount C2, and the coarse adjustment amount calculator 17 Calculate the coarse adjustment amount RC greater than the reference value. Further, the correction calculation unit obtains the gain setting value Gvga of the variable gain amplifier based on the corrected transmission level setting value Pset2 obtained by adding the coarse adjustment amount RC to the transmission level setting value Pset, and based on the fine adjustment amount FC. The band level correction amount Cbb is obtained.

  As a result, in addition to a decrease in the output power of the power amplifier due to a temperature change, even if the output power of the power amplifier decreases according to the frequency of the transmission signal, the fine adjustment correction amount of the total correction amount corresponding to the decrease is based on The band signal level converter 13 adjusts the level, and the variable gain amplifier VGA adjusts the level of the coarse adjustment amount obtained by subtracting the fine adjustment amount from the total correction amount. Thus, also in the second embodiment in which level adjustment is performed in accordance with the transmission frequency in addition to the temperature change, the gain resolution of the variable gain amplifier VGA can be reduced, the circuit configuration can be reduced, and the variable gain can be reduced. A slight correction amount that cannot be handled by the amplifier VGA can be adjusted by the baseband signal level converter 13.

  Next, a method for calculating the frequency correction amount Cf will be described. FIG. 16 is a diagram illustrating a method for calculating the frequency correction amount Cf. The frequency correction amount calculation unit 151 calculates the frequency correction amount Cf. When approximating the change in the output power with respect to the frequency by a linear function, the frequency correction amount Cf is expressed by the following equation (2).

Frequency correction amount Cf = α × (transmission frequency setting value Fset−frequency threshold Fth) + β (2)
α is a frequency correction coefficient, β is a frequency correction intercept, and a frequency threshold Fth is a reference frequency for obtaining a difference from a transmission frequency set value Fset. Preferably, as shown in FIG. 16, since the output power change ratio varies depending on the frequency band, the frequency setting range is divided into a plurality of frequency bands, and a frequency correction coefficient is set for each frequency band.

FIG. 17 is a diagram illustrating an example of parameters used for calculating the frequency correction amount Cf. In FIG. 17, corresponding to the example of FIG. 16, the frequency setting range is divided into four bands, and the lower limit frequency thresholds Fth1, Fth2, Fth3, and Fth4 of each band are set in the storage unit 30. That is, the first band is a band from Fth1 to less than Fth2, the second band is a band from Fth2 to less than Fth3, the third band is a band from Fth3 to less than Fth4, and the fourth band is a band from Fth4 or more. . In this case, the storage unit 30 stores the frequency correction coefficient α1 and frequency correction intercept β1 corresponding to the first band, the frequency correction coefficient α2 and frequency correction intercept β2 corresponding to the second band, and the frequency corresponding to the third band. The correction coefficient α3 and the frequency correction intercept β3, and the frequency correction coefficient α4 and the frequency correction intercept β4 corresponding to the fourth band are stored. As shown in FIG. 16, in the first band, the output power is almost constant with respect to the frequency change, so both the frequency correction coefficient α1 and the frequency correction intercept β1 are set to zero. In the calculation of the above equation (2), α, β, and Fth of the frequency band including the transmission frequency setting value Fset are used. For example, when the transmission frequency setting value Fset is a frequency within the second band, frequency correction is performed. The quantity Cf is
Frequency correction amount Cf = α2 × (transmission frequency setting value Fset−frequency threshold Fth2) + β2 (2 ′)
It becomes.

  In the above description, the frequency setting range is divided into a plurality of bands, and the frequency correction amount Cf is obtained by approximating the change in the output power with respect to the frequency change for each band with a linear function. It is also possible to approximate with a high-order function (for example, a quartic function), and the calculation formula of the frequency correction amount Cf may be given by a high-order function.

  FIG. 18 is a flowchart illustrating the calculation of the total correction amount C2 by the correction calculation unit 14 and the output power correction control using the obtained total correction amount C2 in the second embodiment. The output power correction control in the second embodiment will be described with reference to FIG.

  First, the transmission frequency setting value Fset (kHz) and the transmission level setting value Pset (dBm) are set (S20, S21). The transmission frequency setting value Fset is the frequency of the transmission signal, and is designated from the base station through communication with the base station, for example. When the transmission frequency is different for each adjacent base station, the transmission frequency changes for each handover of the terminal. The setting of the transmission level set value Pset (dBm) is the same process as in step S1 of FIG.

  Next, the correction calculation unit 14 reads the reference temperature Tbase (° C.) and the temperature correction coefficient a (dB / ° C.) stored in the storage unit 30 (S22, S23). Steps S22 and S23 are the same as steps S2 and S3 in FIG.

  Subsequently, the correction calculation unit 14 stores frequency threshold information Fth (kHz), frequency correction coefficient α (dB / 1000 kHz), and frequency correction intercept β (dB) corresponding to the frequency band including the transmission frequency setting value Fset. 30 (S24, S25, S26), the frequency correction amount calculation unit 151 calculates the frequency correction amount Cf according to the above-described equation (2) (S27).

  Next, the correction calculation unit 14 performs output power correction control in steps S28 to S36 according to the temperature change (YES in S37). The correction calculation unit 14 reads the detected temperature Tsensor (° C.) measured by the temperature detection circuit 32 (S28), and the temperature correction amount calculation unit 152 calculates the temperature correction amount Ct according to the equation (1 ′) (S29). Steps S28 and S29 are the same as steps S4 and S5 in FIG. 6, respectively. Then, the correction calculation unit 14 adds the frequency correction amount Cf and the temperature correction amount Ct in the total correction amount calculation unit 150 to obtain the total correction amount C2 (S30). That is, the total correction amount C2 is expressed by the following equation (3).

Total correction amount C2 = Temperature correction amount Ct + Frequency correction amount Cf (3)
FIG. 19 is a diagram showing the relationship between the total correction amount C2 and the detected temperature Tsensor. In comparison with FIG. 7, the total correction amount C2 is a value obtained by adding the frequency correction amount Cf obtained with respect to the transmission frequency setting value Fset to the temperature correction amount Ct that changes according to the temperature, and the detected temperature When Tsensor is the reference temperature Tbase, the temperature correction amount Ct becomes zero, the total correction amount C2 becomes the frequency correction amount Cf, and the total correction is performed with a linear function of the temperature correction coefficient a according to the difference between the detected temperature Tsensor and the reference temperature Tbase. The amount C2 increases or decreases.

  Next, the correction calculation unit 14 obtains a fine adjustment amount FC that is smaller than a reference value (for example, 1.0 dB that is a variable step width of the transmission level setting value) in the total correction amount C2 by the fine adjustment amount calculator 16 (S31). . When the reference value is 1.0 dB, the correction amount (dB) after the decimal point of the total correction amount C2 becomes the fine adjustment amount FC. In this calculation, the remainder obtained by dividing the total correction amount C2 by the reference value 1.0 dB is obtained as the fine adjustment amount FC. Further, the coarse adjustment amount calculator 17 obtains a coarse adjustment amount RC that is greater than or equal to the reference value in the total correction amount C2 (S32). Steps S31 and S32 are the same as steps S6 and S7 in FIG.

  FIG. 20 is a diagram showing the relationship between the fine adjustment amount FC and the detected temperature Tsensor. As in FIG. 8 in the first embodiment, the correction amount after the decimal point in the total correction amount C2 is the fine adjustment amount FC, and the fine adjustment amount is any value between 0 and 1.0 dB. At the reference temperature Tbase, the temperature correction amount Ct is zero, and when the frequency correction amount Cf has a value after the decimal point, as shown in FIG. 20, the fine adjustment amount at the reference temperature Tbase has its frequency. The value after the decimal point of the correction amount Cf.

  FIG. 21 is a diagram showing the relationship between the coarse adjustment amount FC and the detected temperature Tsensor. As in FIG. 9 in the first embodiment, the correction amount obtained by rounding down the decimal portion of the total correction amount C2 becomes the coarse adjustment amount RC, and the coarse adjustment amount RC is 1.0 as the detected temperature Tsensor increases. It is a discrete value in dB steps. In FIG. 21, the frequency correction amount Cf is a value less than 1.0 dB. At the reference temperature Tbase, the temperature correction amount Ct is zero, so the total correction amount C2 is also less than 1.0 dB, and the rough correction at the reference temperature Tbase is achieved. An example in which the adjustment correction amount RC is zero is shown.

  Then, in the correction calculation unit 14, the adder 18 adds the coarse adjustment amount RC to the ideal transmission level setting value Pset to obtain a corrected transmission level setting value Pset2 = Pset + RC (dBm) (S33). . Step S33 is the same processing as step S8 of FIG.

  FIG. 22 is a diagram showing the relationship between the corrected transmission level setting value Pset2 and the detected temperature Tsensor. Similarly to FIG. 10, the corrected transmission level setting value Pset2 is a discrete value obtained by adding the transmission level setting value Pset, which is an ideal value, to the coarse adjustment amount RC in FIG.

  Returning to FIG. 18, the processing after step S34 is the same as the processing after step S9 of the processing of FIG. 6 in the first embodiment. That is, the baseband processing unit 10 converts the corrected transmission level setting value Pset2 (dBm) obtained by the correction calculation unit 14 into a gain setting value Gvga (HEX) using the conversion table 1 shown in FIG. 11 (S34). Similarly, the corrected transmission level setting value Pset2 (dBm) is converted into the baseband level setting value BBset (HEX) by the conversion table 2 shown in FIG. 11 (S34). Further, the baseband processing unit 10 converts the fine adjustment amount FC (dB) into the baseband level correction amount Cbb (HEX) using the conversion table 3 shown in FIG. 11 (S34).

  Subsequently, in the baseband processing unit 10, the adder 19 adds the baseband level correction amount Cbb to the baseband set value BBset to generate a corrected baseband set value BBset2 (S35). Then, the corrected baseband set value BBset2 is converted into the control voltage Vcnt of the amplifier AMP in the baseband level conversion unit 13 shown in FIG. 5 and used for level adjustment of the baseband signals BBin and BBout.

  Further, the gain setting value Gvga is converted into a gain setting signal (voltage) Vvga by the DAC, and is set in the variable gain amplifier VGA in the high frequency circuit unit 20 (S36).

  As described above, also in the second embodiment, as in the first embodiment, the coarse adjustment amount RC (dB) is added to the transmission level setting value Pset (dBm) to obtain the corrected transmission level setting value Pset2. Based on this, the gain of the variable gain amplifier VGA in the high-frequency circuit is controlled. As a result, the output power is corrected by the coarse adjustment amount RC from the output power corresponding to the transmission level set value Pset. Similarly, a corrected baseband level setting value BBset2 obtained by adding the baseband level correction amount Cbb converted from the fine adjustment amount FC to the baseband level setting value BBset converted from the corrected transmission level setting value Pset2 is obtained, and the base The gain of the amplifier AMP of the band signal level conversion unit 13 is controlled. As a result, the output power is further corrected by the fine adjustment amount FC. Thereby, also in the second embodiment, as shown in FIG. 13, the output power TXpower is stably controlled in the vicinity of the output with respect to the ideal transmission level setting value Pset with respect to the temperature change. , A decrease in output power due to a change in the frequency of the transmission signal is also suppressed.

  FIG. 23 is a diagram illustrating output power TXpower with respect to frequency when correction control is performed in the second embodiment. By performing the correction with the total correction amount C2 including the frequency correction amount Cf, the output power TXpower is stably controlled in the vicinity of the output power with respect to the ideal transmission level setting value Pset. The fluctuation range of electric power can be suppressed within ± 0.1 to 0.2 dB.

  According to the wireless transmission device of the second embodiment, fluctuations in output power with respect to temperature changes and frequency changes can be minimized with a small circuit scale.

  The main technical features of the embodiment described above are as follows.

(Appendix 1)
In a wireless transmission device that performs wireless communication,
A baseband signal level converter for adjusting the level of the baseband signal;
A modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal;
A high-frequency circuit unit having a variable gain amplifier for amplifying the high-frequency output signal;
A total correction amount for a transmission level setting value is obtained according to the detected internal temperature of the wireless transmission device, and a fine adjustment amount less than a reference value and a coarse adjustment amount greater than the reference value are obtained from the total correction amount, A gain setting value of the variable gain amplifier is obtained based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value, and a level correction amount of the baseband signal is calculated based on the fine adjustment amount. A correction calculation unit to be obtained,
A radio transmission apparatus that adjusts a level of the baseband signal based on the level correction amount and controls a gain of the variable gain amplifier based on the gain setting value.

(Appendix 2)
In Appendix 1,
The wireless transmission device that obtains the total correction amount based on the detected internal temperature and a temperature correction coefficient of a correction amount that is obtained in advance.

(Appendix 3)
In a wireless communication device that performs wireless communication,
A baseband signal level converter for adjusting the level of the baseband signal;
A high-frequency circuit unit including a modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal; and a variable gain amplifier that amplifies the high-frequency output signal;
A total correction amount for a transmission level setting value is obtained according to the detected internal temperature of the wireless communication device and the frequency of the high-frequency output signal, and a fine adjustment correction amount less than a reference value and a coarse correction amount greater than the reference value are calculated from the total correction amount. And obtaining a gain setting value of the variable gain amplifier based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value, and determining the base value based on the fine adjustment amount. A correction calculation unit for obtaining the level correction amount of the band signal,
A radio transmission apparatus that adjusts a level of the baseband signal based on the level correction amount and controls a gain of the variable gain amplifier based on the gain setting value.

(Appendix 4)
In Appendix 3,
The correction calculation unit obtains a temperature correction amount for the transmission level setting value according to the detected internal temperature, further obtains a frequency correction amount for the transmission level setting value according to the frequency of the high-frequency output signal, A wireless transmission device that obtains the total correction amount from the sum of the temperature correction amount and the frequency correction amount.

(Appendix 5)
In Appendix 4,
The correction calculation unit obtains the temperature correction amount based on the detected internal temperature and a predetermined temperature correction coefficient, and based on the frequency of the high-frequency output signal and the predetermined frequency correction coefficient. A wireless transmission device for obtaining the frequency correction amount.

(Appendix 6)
In any one of appendices 1 to 5,
The correction calculation unit obtains a corrected baseband level setting value obtained by adding a level correction amount of the baseband signal to a baseband level setting value obtained based on the corrected transmission level setting value;
The baseband signal level converting unit adjusts the level of the baseband signal according to the corrected baseband level setting value.

(Appendix 7)
In any one of appendices 1 to 6,
The high-frequency circuit further includes a power amplifier that amplifies an output signal of the variable gain amplifier.

(Appendix 8)
In any one of appendices 1 to 7,
A wireless transmission device in which the reference value is equal to or less than a variable step width of a transmission power setting value.

(Appendix 9)
In the level adjustment method in the wireless transmission device,
Adjust the baseband signal level,
Modulating the adjusted baseband signal to a high frequency output signal;
Amplifying the high frequency output signal;
Calculate the total correction amount for the transmission level setting value according to the detected internal temperature of the wireless transmission device,
Obtain a fine adjustment amount less than a reference value and a coarse adjustment amount greater than the reference value from the total correction amount,
Obtaining a gain setting value of the variable gain amplifier based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value;
Obtaining a level correction amount of the baseband signal based on the fine adjustment amount;
Adjusting the level of the baseband signal based on the level correction amount;
A level adjustment method for controlling the gain of the variable gain amplifier based on the gain setting value.

10: Baseband processing unit 20: High-frequency signal circuit 13: Baseband signal level conversion unit 14: Correction calculation unit
VGA: Variable gain amplifier Pset: Transmission level setting value
Pset2: Correction transmission level setting value Gvga: Gain setting value
C1, C2: Total correction amount FC: Fine adjustment amount
RC: Coarse adjustment amount Cbb: Baseband level correction amount

Claims (6)

In a wireless transmission device that performs wireless communication,
A baseband signal level converter for adjusting the level of the baseband signal;
A modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal;
A high-frequency circuit unit having a variable gain amplifier for amplifying the high-frequency output signal;
A total correction amount for a transmission level setting value is obtained according to the detected internal temperature of the wireless transmission device, and a fine adjustment amount less than a reference value and a coarse adjustment amount greater than the reference value are obtained from the total correction amount, A gain setting value of the variable gain amplifier is obtained based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value, and a level correction amount of the baseband signal is calculated based on the fine adjustment amount. A correction calculation unit to be obtained,
A radio transmission apparatus that adjusts a level of the baseband signal based on the level correction amount and controls a gain of the variable gain amplifier based on the gain setting value. In claim 1,
The wireless transmission device that obtains the total correction amount based on the detected internal temperature and a temperature correction coefficient of a correction amount that is obtained in advance. In a wireless communication device that performs wireless communication,
A baseband signal level converter for adjusting the level of the baseband signal;
A high-frequency circuit unit including a modulation unit that modulates the baseband signal adjusted by the baseband signal level conversion unit into a high-frequency output signal; and a variable gain amplifier that amplifies the high-frequency output signal;
A total correction amount for a transmission level setting value is obtained according to the detected internal temperature of the wireless communication device and the frequency of the high-frequency output signal, and a fine adjustment correction amount less than a reference value and a coarse correction amount greater than the reference value are calculated from the total correction amount. And obtaining a gain setting value of the variable gain amplifier based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value, and determining the base value based on the fine adjustment amount. A correction calculation unit for obtaining the level correction amount of the band signal,
A radio transmission apparatus that adjusts a level of the baseband signal based on the level correction amount and controls a gain of the variable gain amplifier based on the gain setting value. In claim 3,
The correction calculation unit obtains a temperature correction amount for the transmission level setting value according to the detected internal temperature, further obtains a frequency correction amount for the transmission level setting value according to the frequency of the high-frequency output signal, A wireless transmission device that obtains the total correction amount from the sum of the temperature correction amount and the frequency correction amount. In claim 4,
The correction calculation unit obtains the temperature correction amount based on the detected internal temperature and a predetermined temperature correction coefficient, and based on the frequency of the high-frequency output signal and the predetermined frequency correction coefficient. A wireless transmission device for obtaining the frequency correction amount. In the level adjustment method in the wireless transmission device,
Adjust the baseband signal level,
Modulating the adjusted baseband signal to a high frequency output signal;
Amplifying the high frequency output signal;
Calculate the total correction amount for the transmission level setting value according to the detected internal temperature of the wireless transmission device,
Obtain a fine adjustment amount less than a reference value and a coarse adjustment amount greater than the reference value from the total correction amount,
Obtaining a gain setting value of the variable gain amplifier based on a corrected transmission level setting value obtained by adding the coarse adjustment amount to the transmission level setting value;
Obtaining a level correction amount of the baseband signal based on the fine adjustment amount;
Adjusting the level of the baseband signal based on the level correction amount;
A level adjustment method for controlling the gain of the variable gain amplifier based on the gain setting value.

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