JP2012195724A - Radio transmitter, frequency characteristic correction method, and temperature characteristic correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio transmitter and a frequency characteristic correction method for a transmission circuit of the radio transmitter, which can easily obtain a frequency characteristic correction value of the transmission circuit in the case of transmission power with which a detector circuit outputting detection voltage by detecting part of antenna input power at an antenna end of the transmission circuit does not work.SOLUTION: A frequency characteristic correction value of a transmission circuit 30 is calculated from a correction value in a state where a detector circuit 16 is activated, and an analog voltage based on the correction value and an analog voltage having a fixed value output from a gain control part 19 are made to be added and output to a variable gain amplifier 10 of the transmission circuit 30 in the case of low transmission power with which the detector circuit 16 does not work. Thereby, the frequency characteristic correction value of the transmission circuit 30 can easily obtained in the case of transmission power with which the detector circuit 16 does not work.

Description

  The present invention provides a radio transmitter including a feedback circuit that feeds back antenna input power to the transmission power control side, a frequency characteristic correction method, for the purpose of suppressing fluctuations in transmission power due to characteristic changes of a plurality of components constituting the transmission circuit The present invention relates to a temperature characteristic correction method.

  In a wireless transmitter used in a wireless communication device such as a mobile phone, the above-described feedback circuit is often employed. The feedback circuit has a detection circuit for acquiring transmission power (that is, antenna input power) at the antenna input end of the wireless transmitter. Since the detection voltage obtained from this detection circuit is proportional to the transmission power, the feedback circuit operates only in the transmission power range in which the detection voltage can be obtained, and does not operate below that.

  As a wireless transmitter having the above-described detection circuit, those described in Patent Documents 1 to 3 are known. Patent Document 1 has transmission power level control means, stores current value information and transmission power level information flowing into the transmission power amplifier in a memory, and sets the current and transmission power of the transmission power amplifier at the time of readjustment. Is described in comparison with the memory contents to determine whether the adjustment is good or bad. In Patent Document 2, a correction value corresponding to the output level of the detection circuit is read from the storage circuit, converted to analog, and then output to the AGC amplifier in the previous stage of the power amplifier to control the gain of the amplifier. The technology is described. Patent Document 2 also describes that the gain of the AGC amplifier is controlled by detecting the ambient temperature. In Patent Document 3, taking into account variations in the detection characteristics of the detection circuit, data conversion tables T1, T2, and T3 are prepared, and an optimum table number is designated by data D. The transmission power set data is corrected using the table T4 so as to compensate the frequency characteristics of the detector, and is corrected using the table T5 so as to compensate the temperature characteristics, and the corrected transmission power set data and output power data are corrected. Describes a technique for controlling in advance the amount of attenuation of a variable attenuator provided on the front side of the RF amplifier so as to match.

JP 2008-245058 A JP 2006-270276 A JP-A-5-003440

  The antenna input power at the antenna end of the transmission circuit (excluding the feedback circuit) varies for each channel (frequency) to be used, depending on the frequency characteristics of a plurality of components constituting the transmission circuit. This frequency characteristic depends on the frequency characteristic when the detection circuit operates. Usually, since the transmission power needs to be constant for each channel, it is necessary to correct the deviation of the transmission power for each channel when the detector circuit operates and when it does not operate. In particular, when the number of channels is large or a multi-band wireless communication device is used, the number of corrections becomes enormous, so that a great deal of time is spent adjusting the correction values of the transmission circuit using an external measuring instrument. .

  In addition, in a radio transmitter employing a configuration in which a feedback circuit is operated only within a transmission power range in which a detection voltage can be obtained, even if the frequency characteristics of the transmission circuit are adjusted, a detection voltage cannot be obtained when the frequency is below the transmission power range Therefore, the frequency characteristic of the detection circuit cannot be calculated. Similarly, even if the temperature characteristic of the transmission circuit is adjusted, the temperature characteristic of the detection circuit cannot be calculated when it is below the transmission power range. Among Patent Documents 1 to 3 described above, Patent Documents 1 and 2 describe that the frequency characteristic correction value of the transmission circuit is obtained from the stored frequency characteristic correction value. The point that the frequency characteristic of the detection circuit is obtained from the detection voltage when the frequency characteristic of the circuit is adjusted is described. However, in any of Patent Documents 1 to 3, the transmission voltage range within which the detection voltage can be obtained is described. Therefore, the frequency characteristic of the detection circuit cannot be calculated when the frequency is below the transmission power range.

  The present invention has been made in view of such circumstances, and the frequency characteristics of the transmission circuit when the detection circuit that detects a part of the antenna input power at the antenna end of the transmission circuit and outputs a detection voltage does not work. It is an object of the present invention to provide a wireless transmitter, a frequency characteristic correction method, and a temperature characteristic correction method that can easily obtain a correction value.

  A radio transmitter according to the present invention detects a part of antenna input power at an antenna end of a transmission circuit having a variable gain amplifier whose gain is changed by an analog voltage input from the outside, and outputs a detection voltage The detection circuit to be output, the reference voltage output unit that outputs the reference voltage when adjusted to a desired transmission power, and the detection voltage output from the detection circuit and the reference voltage output from the reference voltage output unit are compared. A comparator for extracting the difference, a gain control unit for controlling the gain of the variable gain amplifier according to the output of the comparator, and the transmission based on the output of the comparator at a low transmission power at which the detection circuit does not operate. A frequency characteristic correction value calculating unit for calculating a correction value for correcting the frequency characteristic of the circuit; and the frequency characteristic correction value. A transmission circuit frequency characteristic storage unit that stores the correction value calculated by the output unit; an analog voltage based on the correction value stored in the transmission circuit frequency characteristic storage unit at a low transmission power at which the detection circuit does not operate; And an adder that adds a fixed-value analog voltage output from the gain control unit and outputs the sum to the variable gain amplifier.

  The present invention calculates a frequency characteristic correction value of a transmission circuit from a correction value in a state in which the detection circuit is operated, and outputs an analog voltage based on the correction value and a gain control unit at a low transmission power at which the detection circuit does not operate. Since the fixed value analog voltage is added and output to the variable gain amplifier, it is possible to easily obtain the frequency characteristic correction value of the transmission circuit when the transmission power is such that the detection circuit does not work.

1 is a block diagram showing a schematic configuration of a wireless transmitter according to Embodiment 1 of the present invention. The block diagram which shows schematic structure of the radio | wireless transmitter which concerns on Embodiment 2 of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments for carrying out the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a radio transmitter according to Embodiment 1 of the present invention. In the figure, the wireless transmitter 1 of the present embodiment includes a variable gain amplifier 10, a filter 11, a fixed gain amplifier 12, a filter 13, a directional coupler 14, an antenna 15, a detection circuit 16, a reference voltage output unit 17, A comparator 18, a gain control unit 19, a frequency characteristic correction value calculation unit 20, a transmission circuit frequency characteristic storage unit 21, and an adder 22 are provided. The variable gain amplifier 10, the filter 11, the fixed gain amplifier 12, the filter 13, and the antenna 15 constitute a transmission circuit 30. The directional coupler 14, the detection circuit 16, the reference voltage output unit 17, the comparator 18, and the gain control unit 19 constitute a feedback circuit 40. The frequency characteristic correction value calculation unit 20, the transmission circuit frequency characteristic storage unit 21, and the adder 22 constitute a frequency characteristic correction circuit 50. The gain is a gain.

  In the transmission circuit 30, the variable gain amplifier 10 amplifies the input signal with the set gain and outputs the amplified signal. The filter 11 removes unnecessary waves contained in the signal amplified by the variable gain amplifier 10. The fixed gain amplifier 12 amplifies and outputs the signal that has passed through the filter 11. The filter 13 removes unnecessary waves contained in the signal amplified by the fixed gain amplifier 12.

  In the feedback circuit 40, the directional coupler 14 extracts a part of the input power to the antenna 15. The detection circuit 16 detects the input power taken out by the directional coupler 14 and outputs a detection voltage proportional to the power. The detection voltage output from the detection circuit 16 is an analog voltage. The reference voltage output unit 17 outputs a reference voltage corresponding to transmission power adjusted in advance according to the transmission power level. The comparator 18 compares the detection voltage output from the detection circuit 16 with the reference voltage output from the reference voltage output unit 17, extracts the difference, and outputs the difference. The output of the comparator 18 (hereinafter referred to as “comparator output”) has a different value for each channel. The comparator output for each channel is output to the frequency characteristic correction value calculation unit 20 of the frequency characteristic correction circuit 50. The reference voltage output from the reference voltage output unit 17 is a voltage when adjusted with a desired transmission power, and compensates the frequency characteristics of the detection circuit 16. That is, unless the frequency characteristic of the detection circuit 16 is compensated, the signal fed back to the variable gain amplifier 10 of the transmission circuit 30 is affected by the frequency characteristic of the detection circuit 16, and the transmission power cannot be set to the target value. For this purpose, a reference voltage is generated. When there is a comparator output, the gain control unit 19 outputs an analog voltage for controlling the gain of the variable gain amplifier 10 of the transmission circuit 30 according to the output. By feeding back the comparator output to the variable gain amplifier 10 of the transmission circuit 30, the variation in the transmission power is corrected.

  The gain control unit 19 outputs an analog voltage corresponding to preset transmission power when there is no comparator output. That is, when the transmission power is low and the detection circuit 16 does not operate, an analog voltage corresponding to the preset transmission power is output. The analog voltage output from the gain control unit 19 is added to the analog voltage output from the transmission circuit frequency characteristic storage unit 21 by the adder 22 and provided to the variable gain amplifier 10. As described above, when the transmission power is low and the detection circuit 16 does not operate, the antenna input power is determined by the gain control unit 19 and the transmission circuit frequency characteristic storage unit 21.

  The frequency characteristic correction value calculation unit 20 calculates a correction value of the frequency characteristic in the transmission circuit 30 when the transmission power is low and the detection circuit 16 does not operate. The transmission circuit frequency characteristic storage unit 21 stores the correction value calculated by the frequency characteristic correction value calculation unit 20. When the transmission power is low and the detection circuit 16 does not operate, the transmission circuit frequency characteristic storage unit 21 converts the stored correction value into an analog voltage and outputs the analog voltage. Since the transmission circuit frequency characteristic storage unit 21 does not store the correction value at the initial stage, a process for storing the correction value before the factory shipment of the wireless transmitter 1 is required. Here, the frequency characteristic correction method of the transmission circuit 30 will be described.

  Assume that a fixed-value analog voltage is output from the gain control unit 19 in a state where no data is stored in the transmission circuit frequency characteristic storage unit 21. At this time, it is assumed that the antenna input power when transmission is performed in the order of the channels f1, f2, and f3 is p1, p2, and p3 and the detection voltages d1, d2, and d3. Here, assuming that f2 is a reference channel, the frequency characteristics of the antenna input power and the detection voltage are f1 (p1-p2), (d1-d2), f3 (p3-p2), and (d3-d2). At this time, in order to satisfy p1 = p2 = p3, it is necessary to correct f1 (d1-d2) and f3 (d3-d2) for the comparator output. Therefore, the detection circuit 16 is operated by increasing the transmission power, and the correction of (d−d2) is applied to f1 and (d3−d2) is applied to f3. Accordingly, the correction values fed back from the frequency characteristic correction value calculation unit 20 to the gain control unit 19 become the correction values f1 (p1-p2) and f3 (p3-p2) in the transmission circuit frequency characteristics. By storing these correction values in the transmission circuit frequency characteristic storage unit 21, a correction value of the frequency characteristic of the transmission circuit 30 is obtained.

The frequency characteristic correction process of the transmission circuit 30 is represented by steps as follows.
(1) In a state in which a fixed-value analog voltage is output from the gain control unit 19, transmission is performed in the order of the channels f1, f2, and f3 with transmission power at which the detection circuit 16 operates. Step for obtaining antenna input powers p1, p2, p3 and detection voltages d1, d2, d3 corresponding to f3 (2) Frequency characteristics f1 (p1-p2), f3 (frequency characteristics of antenna input power when channel f2 is used as a reference channel d3−d2) and frequency characteristics (d1−d2) and frequency characteristics (d3−d2) of the detection voltage (3) Correction value for the comparator output in which all the antenna input powers corresponding to the channels f1, f2, and f3 are equal. Step of obtaining analog voltage and gain control based on the correction value obtained in the above step at low transmission power at which the detection circuit 16 does not operate A step of adding the fixed value analog voltage output from the unit 19 and outputting it to the variable gain amplifier 10 (4) A step of storing the correction value obtained in the step

Next, the operation of the wireless transmitter 1 according to this embodiment will be described.
When the input signal Si is given to the transmission circuit 30, the input signal Si is amplified by the variable gain amplifier 10 and the fixed gain amplifier 12, and unnecessary components are removed by the filters 11 and 13, and the input signal Si is input to the antenna 15. 15 is emitted. Here, even if the input signal of the variable gain amplifier 10 is a constant value, the antenna input power fluctuates due to changes in the characteristics of each component of the transmission circuit 30 (amplifier gain fluctuation due to temperature, etc.). Correction is performed by the feedback circuit 40. That is, a part of the antenna input power is distributed to the detection circuit 16 by the directional coupler 14 of the feedback circuit 40. A part of the distributed antenna input power is detected by the detection circuit 16, a detection voltage proportional to the power is output, the detection voltage is compared with a reference voltage when adjusted with a desired transmission power, and a difference is extracted. . This difference is fed back to the variable gain amplifier 10 to correct the variation in transmission power.

  On the other hand, when the transmission power is low and the detection circuit 16 does not operate, the fixed value analog voltage output from the gain control unit 19 and the correction value in the transmission circuit frequency characteristic output from the transmission circuit frequency characteristic storage unit 21 are used. The analog voltage based thereon is added by the adder 22 and supplied to the variable gain amplifier 10. Thereby, even when the transmission power is low and the detection circuit 16 does not operate, the frequency characteristic of the transmission circuit 30 is corrected and the transmission power of the target value can be transmitted.

  As described above, according to the wireless transmitter 1 of the present embodiment, the frequency characteristic correction value of the transmission circuit 30 is calculated from the frequency characteristic correction value in a state where the detection circuit 16 is operated, and the detection circuit 16 does not operate. Since the analog voltage based on the frequency characteristic correction value and the fixed value analog voltage output from the gain control unit 19 are added and transmitted to the variable gain amplifier 10 of the transmission circuit 30 at the time of transmission power, the detection circuit 16 It is possible to easily obtain the frequency characteristic correction value of the transmission circuit 30 when the transmission power does not work.

  Note that a program describing the frequency characteristic correction processing of the transmission circuit 30 in the wireless transmitter 1 of the present embodiment is a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), It is also possible to store and distribute in a storage medium such as a magneto-optical disk or a semiconductor memory.

(Embodiment 2)
Next, the radio transmitter according to Embodiment 2 of the present invention will be described.
FIG. 2 is a block diagram showing a schematic configuration of a radio transmitter according to Embodiment 2 of the present invention. In the figure, the same reference numerals are given to the portions common to FIG. 1 described above, and the description thereof is omitted.

  The wireless transmitter 1 according to the first embodiment described above includes a frequency characteristic correction value calculation unit 20 that calculates a correction value for correcting the frequency characteristic of the transmission circuit 30 at low transmission power when the detection circuit 16 does not operate. Although the transmission circuit frequency characteristic storage unit 21 that stores the correction value calculated by the frequency characteristic correction value calculation unit 20 is provided, the wireless transmitter 2 according to the second embodiment has the temperature characteristic of the transmission circuit 30. The temperature characteristic correction value calculation unit 25 that calculates a correction value for correcting the temperature and the transmission circuit temperature characteristic storage unit 26 that stores the correction value calculated by the temperature characteristic correction value calculation unit 25 are provided. . The temperature characteristic correction value calculation unit 25, the transmission circuit temperature characteristic storage unit 26, and the adder 22 constitute a temperature characteristic correction circuit 60. Only differences from the wireless transmitter 1 according to the first embodiment will be described below.

  The temperature characteristic correction value calculation unit 25 calculates a correction value of the temperature characteristic in the transmission circuit 30 when the transmission power is low and the detection circuit 16 does not operate. The transmission circuit temperature characteristic storage unit 26 stores the correction value calculated by the temperature characteristic correction value calculation unit 25. The comparator output has a different value for each temperature, and the comparator output for each temperature is output to the temperature characteristic correction value calculation unit 25 of the temperature characteristic correction circuit 60. The gain of the variable gain amplifier 10 of the transmission circuit 30 is adjusted by an analog voltage obtained by adding the analog voltage output from the gain control unit 19 and the analog voltage output from the transmission circuit temperature characteristic storage unit 26. Since the transmission circuit temperature characteristic storage unit 26 does not store the correction value at the initial stage, processing for storing the correction value is required before the wireless transmitter 2 of the present embodiment is shipped from the factory. Here, a temperature characteristic correction method of the transmission circuit 30 will be described.

  Assume that a fixed-value analog voltage is output from the gain control unit 19 in a state where no data is stored in the transmission circuit temperature characteristic storage unit 26. At this time, it is assumed that the antenna input power when the ambient temperature of the device is changed in the order of t1, t2, and t3 is p1, p2, and p3 and the detection voltages d1, d2, and d3. Here, when t2 is a reference temperature, the temperature characteristics of the antenna input power and the detected voltage are t1 (p1-p2), (d1-d2), t3 (p3-p2), and (d3-d2). At this time, in order to satisfy p1 = p2 = p3, it is necessary to correct t1 (d1-d2) and t3 (d3-d2) for the comparator output. Therefore, the detection circuit 16 is operated by increasing the transmission power, and the correction of (d−d2) is applied to t1 and (d3−d2) is applied to t3. Thereby, the correction values fed back from the temperature characteristic correction value calculation unit 25 to the gain control unit 19 become the correction values t1 (p1-p2) and t3 (p3-p2) in the transmission circuit temperature characteristics. By storing these correction values in the transmission circuit temperature characteristic storage unit 26, a correction value for the temperature characteristic of the transmission circuit 30 is obtained.

The temperature characteristic correction process of the transmission circuit 30 is represented by steps as follows.
(1) In a state where a fixed-value analog voltage is output from the gain control unit 19, the ambient temperature of the device is changed in the order of t1, t2, and t3 with the transmission power at which the detection circuit 16 operates. Step for obtaining antenna input powers p1, p2, p3 and detection voltages d1, d2, d3 corresponding to temperatures t1, t2, t3 (2) Temperature characteristics t1 of antenna input power when ambient temperature t2 is a reference temperature ( p1−p2), t3 (d3−d2), and temperature characteristics (d1−d2) and (d3−d2) of the detected voltage are obtained. (3) All antenna input powers corresponding to the ambient temperatures t1, t2, and t3 Step for obtaining a correction value for comparator outputs equal to each other When the transmission power is low and the detection circuit 16 does not operate, the analog voltage based on the correction value obtained in the above step and the gain control unit 1 A step of adding the fixed value analog voltage output from the step 9 and outputting the sum to the variable gain amplifier 10 (4) A step of storing the correction value obtained in the step

Next, the operation of the wireless transmitter 2 of the present embodiment will be described.
When the input signal Si is given to the transmission circuit 30, the input signal Si is amplified by the variable gain amplifier 10 and the fixed gain amplifier 12, and unnecessary components are removed by the filters 11 and 13, and the input signal Si is input to the antenna 15. 15 is emitted. Here, even if the input signal of the variable gain amplifier 10 is a constant value, the antenna input power fluctuates due to characteristic changes of each component of the transmission circuit 30 (amplifier gain fluctuation due to temperature, etc.). It is corrected by the circuit 40. That is, a part of the antenna input power is distributed to the detection circuit 16 by the directional coupler 14 of the feedback circuit 40. A part of the distributed antenna input power is detected by the detection circuit 16, a detection voltage proportional to the power is output, the detection voltage is compared with a reference voltage when adjusted with a desired transmission power, and a difference is extracted. . This difference is fed back to the variable gain amplifier 10 to correct the variation in transmission power.

  On the other hand, when the transmission power is low and the detection circuit 16 does not operate, the fixed value analog voltage output from the gain control unit 19 and the correction value in the transmission circuit temperature characteristic output from the transmission circuit temperature characteristic storage unit 26 are used. The analog voltage based thereon is added by the adder 22 and supplied to the variable gain amplifier 10. Thereby, even when the transmission power is low and the detection circuit 16 does not operate, the temperature characteristic of the transmission circuit 30 is corrected and the transmission power of the target value can be transmitted.

  As described above, according to the wireless transmitter 2 of the present embodiment, the temperature characteristic correction value of the transmission circuit 30 is calculated from the temperature characteristic correction value in a state where the detection circuit 16 is operated, and the detection circuit 16 does not operate. At the time of transmission power, the analog voltage based on the temperature characteristic correction value and the fixed value analog voltage output from the gain control unit 19 are added and output to the variable gain amplifier 10 of the transmission circuit 30. It is possible to easily obtain the temperature characteristic correction value of the transmission circuit 30 when the transmission power does not work.

  The radio transmitter 2 of the present embodiment does not include the frequency characteristic correction value calculation unit 20 and the transmission circuit frequency characteristic storage unit 21 of the radio transmitter 1 of the first embodiment, but may include the same ones. Of course it is possible.

  In addition, a program describing the temperature characteristic correction processing of the transmission circuit 30 in the wireless transmitter 2 of the present embodiment is stored in a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD-ROM, DVD, etc.), It is also possible to store and distribute in a storage medium such as a magneto-optical disk or a semiconductor memory.

  The present invention can be applied to a wireless transmitter used in a wireless communication device such as a mobile phone.

DESCRIPTION OF SYMBOLS 1, 2 Radio transmitter 10 Variable gain amplifier 11, 13 Filter 12 Fixed gain amplifier 14 Directional coupler 15 Antenna 16 Detection circuit 17 Reference voltage output part 18 Comparator 19 Gain control part 20 Frequency characteristic correction value calculation part 21 Transmission circuit frequency Characteristic storage unit 22 Adder 25 Temperature characteristic correction value calculation unit 26 Transmission circuit temperature characteristic storage unit 30 Transmission circuit 40 Feedback circuit 50 Frequency characteristic correction circuit 60 Temperature characteristic correction circuit

Claims (6)

A transmission circuit having a variable gain amplifier whose gain changes according to an analog voltage input from the outside;
A detection circuit that detects a part of the antenna input power at the antenna end of the transmission circuit and outputs a detection voltage;
A reference voltage output unit that outputs a reference voltage when adjusted to a desired transmission power;
A comparator that compares the detection voltage output from the detection circuit and the reference voltage output from the reference voltage output unit, and extracts a difference;
A gain control unit for controlling the gain of the variable gain amplifier according to the output of the comparator;
A frequency characteristic correction value calculating unit that calculates a correction value for correcting the frequency characteristic of the transmission circuit based on the output of the comparator at the time of low transmission power at which the detection circuit does not operate;
A transmission circuit frequency characteristic storage unit that stores the correction value calculated by the frequency characteristic correction value calculation unit;
The variable gain amplifier by adding an analog voltage based on a correction value stored in the transmission circuit frequency characteristic storage unit and an analog voltage of a fixed value output from the gain control unit at low transmission power at which the detection circuit does not operate An adder that outputs to
With wireless transmitter. A transmission circuit having a variable gain amplifier whose gain is changed by an analog voltage input from the outside, a detection circuit for detecting a part of the antenna input power at the antenna end of the transmission circuit and outputting a detection voltage, and a desired transmission A reference voltage output unit that outputs a reference voltage when adjusted to power, a comparator that compares a detection voltage output from the detection circuit with a reference voltage output from the reference voltage output unit, and extracts a difference; In the method for correcting frequency characteristics of a transmission circuit of a wireless transmitter, comprising: a gain control unit that controls the gain of the variable gain amplifier according to the output of the comparator;
In a state where a fixed-value analog voltage is output from the gain control unit, transmission is performed in order on a plurality of channels with transmission power at which the detection circuit operates, and antenna input power and detection voltage corresponding to each channel are transmitted. Step to get the
Determining one of the plurality of channels as a reference channel and obtaining frequency characteristics of antenna input power and detection voltage for the reference channel; and
Obtaining a correction value for the output of the comparator in which all of the antenna input power corresponding to each channel are equal;
A step of adding an analog voltage based on the correction value obtained in the step and a fixed value analog voltage output from the gain control unit to the variable gain amplifier at a low transmission power at which the detection circuit does not operate; When,
A method of correcting frequency characteristics of a transmission circuit of a wireless transmitter comprising:   The method for correcting a frequency characteristic of a transmission circuit of a wireless transmitter according to claim 2, further comprising a step of storing the correction value obtained in the step. A transmission circuit having a variable gain amplifier whose gain changes according to an analog voltage input from the outside;
A detection circuit that detects a part of the antenna input power at the antenna end of the transmission circuit and outputs a detection voltage;
A reference voltage output unit that outputs a reference voltage when adjusted to a desired transmission power;
A comparator that compares the detection voltage output from the detection circuit and the reference voltage output from the reference voltage output unit, and extracts a difference;
A gain control unit for controlling the gain of the variable gain amplifier according to the output of the comparator;
A temperature characteristic correction value calculation unit that calculates a correction value for correcting the temperature characteristic of the transmission circuit based on the output of the comparator at the time of low transmission power at which the detection circuit does not operate;
A transmission circuit temperature characteristic storage unit that stores the correction value calculated by the temperature characteristic correction value calculation unit;
The variable gain amplifier by adding an analog voltage based on a correction value stored in the transmission circuit temperature characteristic storage unit and an analog voltage of a fixed value output from the gain control unit at low transmission power at which the detection circuit does not operate An adder that outputs to
With wireless transmitter. A transmission circuit having a variable gain amplifier whose gain is changed by an analog voltage input from the outside, a detection circuit for detecting a part of the antenna input power at the antenna end of the transmission circuit and outputting a detection voltage, and a desired transmission A reference voltage output unit that outputs a reference voltage when adjusted to power, a comparator that compares a detection voltage output from the detection circuit with a reference voltage output from the reference voltage output unit, and extracts a difference; In the method for correcting temperature characteristics of a radio transmitter, comprising: a gain control unit that controls the gain of the variable gain amplifier according to the output of the comparator;
The antenna input power corresponding to each temperature is obtained by sequentially changing the ambient temperature of the device to a plurality of temperatures with the transmission power at which the detection circuit operates in a state where a fixed value analog voltage is output from the gain control unit. And obtaining a detection voltage;
Determining one of the plurality of temperatures as a reference temperature and obtaining temperature characteristics of the antenna input power and the detection voltage with respect to the reference temperature; and
Obtaining a correction value for the output of the comparator in which all of the antenna input power corresponding to each temperature are equal;
A step of adding an analog voltage based on the correction value obtained in the step and a fixed value analog voltage output from the gain control unit to the variable gain amplifier at a low transmission power at which the detection circuit does not operate; When,
A method for correcting temperature characteristics of a wireless transmitter comprising:   The method for correcting a temperature characteristic of a wireless transmitter according to claim 5, further comprising a step of storing the correction value obtained in the step.

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