JP3916897B2 - Measuring instrument with calibration function and calibration method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to, for example, a measuring device that measures output power, frequency, modulation accuracy, adjacent channel leakage, modulation bandwidth, reception sensitivity, etc. of a mobile terminal, and calibrates transmission output level and reception level. The present invention relates to a measuring instrument with a calibration function to be performed and a calibration method using the same.
[0002]
[Prior art]
For example, a measuring instrument that measures the output power, frequency, modulation accuracy, adjacent channel leakage, modulation bandwidth, reception sensitivity, etc. of a mobile terminal needs to calibrate the transmission output level and reception level in order to perform more accurate measurements. It is performed accordingly.
[0003]
FIG. 4 shows a schematic configuration of a conventional measuring instrument when the transmission output level and the reception level are calibrated.
[0004]
The measuring device 51 shown in FIG. 4 has a quadrature modulator 52 that outputs a baseband signal. An attenuator (ATT) 53 for adjusting the voltage level is connected to the output of the quadrature modulator 52. The output of the attenuator 53 is connected to one input of the transmission side mixer 54. A transmission-side oscillator 55 is connected to the other input of the transmission-side mixer 54. The output of the transmission side mixer 54 is connected to the first coupler 57 via the amplifier 56. A level detector 58 is connected to the output of the amplifier 56, and one input of the comparator 59 is connected to the output of the level detector 58. A reference voltage is input to the other input of the comparator 59. The comparator 59 compares the reference voltage with the detection signal (voltage value) of the level detector 58 and outputs the difference signal.
[0005]
An A / D converter 60 is connected to the output of the comparator 59. A CPU 61 is connected to the A / D converter 60, and a memory 62 and a D / A converter 63 are connected to the CPU 61. Between the attenuator 53 and the comparator 59, a contact is selectively switched between the comparator 59 and the attenuator 53 or between the D / A converter 63 and the attenuator 53 so as to be conductively connected. The switch 64 is connected.
[0006]
Here, an ALC (Automatic Level Control) circuit is formed by the attenuator 53, the transmission-side mixer 54, the amplifier 56, the level detector 58, and the comparator 59 in a state where the contact of the switching unit 64 is switched to the comparator 59 side. is doing. Then, the output level of the transmission signal is detected by the level detector 58, the detected voltage is compared with the reference voltage by the comparator 59, and the voltage value corresponding to the difference signal is set as the attenuation amount of the attenuator 53. The output level is adjusted to a predetermined level. Normally, ALC is OFF in a state where a modulation signal is output. This is because the output level of the modulation signal constantly fluctuates violently, and it is difficult to detect the effective value of the modulation signal at a frequency of several GHz. This is because it is difficult to obtain.
[0007]
Further, as a receiving side configuration, a receiving side mixer 65 is connected to the first coupler 57. A reception-side oscillator 66 is connected to the reception-side mixer 65. A level measuring device 67 is connected to the output of the receiving side mixer 65. A second coupler 68 is connected to the first coupler 57, and a power sensor 69 and an antenna 70 are connected to the second coupler 68.
[0008]
Next, the operation in the case of performing the calibration of the transmission output level and the calibration of the reception level in the measuring instrument 51 having the above-described configuration will be described with reference to the flowcharts of FIGS.
[0009]
When the transmission output level is calibrated, a non-modulated signal (CW) is output from the quadrature modulator 52 as shown in FIG. In order to generate a non-modulated signal from the quadrature modulator 52, each of the I and Q signals that are input to the quadrature modulator 52 may be fixed to a constant DC voltage. Alternatively, a sine wave whose phase difference between I and Q is +90 or −90 degrees may be input. In this case, if the effective value of the voltage amplitude of the sine wave is the same as the voltage value when a fixed DC voltage is applied, the frequency is I, Q at the same output level as when a fixed voltage is applied. The frequency is shifted by the frequency of the input sine wave (ST21). Subsequently, the contact of the switch 64 is switched to the comparator 59 side, and ALC is turned ON (ST22). Then, the voltage of the amplifier 56 in that state is detected by the level detector 58, the difference signal from the comparator 59 is A / D converted by the A / D converter 60, and the value is stored in the memory 62 (ST23). . Next, the contact of the switch 64 is switched to the D / A converter 63 side, and ALC is turned OFF (ST24). Then, the voltage stored in the memory 62 is applied from the D / A converter 63 to the attenuator 53 (ST25). Thereafter, the modulation signal is output (ST26). At this time, if the effective values of the amplitudes of the modulation signals I and Q to the quadrature modulator 52 are set to the same amplitude as the amplitude of the unmodulated output at ST21, the transmission output level is the same as that when the ALC is ON. The state can be reproduced, and a stable output level that is not affected by temperature fluctuations and changes with time of the mixer 54 and the amplifier 56 can be obtained. Since the modulation signals I and Q are usually generated using a D / A converter, the amplitude is extremely stable as compared with the mixer 54 and the amplifier 56. This operation is executed every time the transmission output frequency is changed. Alternatively, the user executes it manually when necessary.
[0010]
Next, when the reception level is calibrated, as shown in FIG. 6, first, signals of all frequencies in the used frequency band are generated from an external signal generator and input from the antenna 70, and the level for each frequency. Measure. Then, the power sensor 69 is calibrated by correcting the level for each frequency by the difference from the level when a reference signal (for example, a signal of 0 dBm) is input (ST31). Next, a signal having a level at which the measuring instrument 51 operates is input from the antenna 70 (ST32). Subsequently, the level of the signal input from the outside is measured by the power sensor 69 (ST33). Similarly, the level of the signal input from the outside is measured by the level measuring device 67 (ST34). Then, the difference between the value measured by the level measuring device 67 and the value measured by the power sensor 69 is used as a correction value (ST35).
[0011]
[Problems to be solved by the invention]
However, in the conventional measuring instrument 51 described above, when the transmission output level is calibrated, it is necessary to execute it every time the transmission output frequency is changed or manually by the user. It was. Also, it is usually necessary to calibrate the transmission output level every time the transmission output frequency is changed. If this is neglected, the output of the transmission signal is not guaranteed, so that sufficient measurement accuracy cannot be obtained. Invite.
[0012]
In the conventional configuration shown in FIG. 4, when the reception level is calibrated, an external signal generator is required, two couplers 57 and 68 having coupling losses are required, and the reception level is calibrated. Since the power sensor 69 with a built-in device as a reference unit when performing the measurement is indispensable, there is a problem that not only the configuration itself is complicated, but also causes of measurement errors are increased. In addition, since the response speed is slow and the power sensor itself having a narrow dynamic range needs to be calibrated, there is a problem that not only the calibration procedure is troublesome but also the measurement time of the whole measurement including calibration is required.
[0013]
Therefore, the present invention has been made in view of the above problems, and a measuring instrument with a calibration function capable of improving the measurement accuracy by outputting a guaranteed transmission signal and shortening the measurement time and the same are used. The purpose is to provide a calibration method.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a measuring instrument with a calibration function according to the present invention detects the output level of a transmission signal and outputs a value corresponding to the output level as a detection voltage value, and the level detection The detection voltage value output from the unit and the reference voltage are compared, the comparison unit 13 that outputs the difference voltage, the difference voltage output from the comparison unit, and the signal value at the voltage value corresponding to the difference voltage An ALC circuit 19 having a level adjustment unit 8 for adjusting the output level;
An A / D converter 14 for converting the difference voltage of the comparator into digital value data and outputting the data;
A controller 15 for holding data from the A / D converter for each transmission output frequency, and outputting data held in correspondence with the transmission output frequency;
A D / A converter 17 for outputting the digital value data output from the controller as an analog voltage value;
A switching unit 18 for turning on and off the loop of the ALC circuit so that the differential voltage of the comparison unit or the analog voltage value from the D / A conversion unit is selectively set in the level adjustment unit;
A coupler 2 for outputting a transmission signal from the ALC circuit from the antenna 5 and for branching and synthesizing the signal so as to receive an external signal via the antenna;
A short-circuit route switching unit 6 that selectively switches between a route for receiving a signal from the antenna via the coupler and a short-circuit route for allowing the transmission signal to pass without passing through the coupler;
A level measurement unit 22 that measures the level of an external signal input from the antenna via the coupler or the transmission signal input via the short-circuit route;
When the short-circuit route switching unit is selectively switched to the short-circuit route, an unmodulated signal is input to the level adjustment unit, and the level is adjusted while switching the transmission output frequency from the lowest frequency to the highest frequency in a predetermined frequency step. The measurement unit measures the level for each frequency and calibrates the reception level based on the measurement result.
[0015]
A measuring instrument with a calibration function according to another invention is the measuring instrument with a calibration function according to claim 1,
When the non-modulated signal is input to the level adjustment unit 8 and the loop of the ALC circuit 19 is ON, the comparison unit at each frequency while switching the transmission output frequency in a predetermined frequency step from the lowest frequency to the maximum frequency 13 is stored as digital value data of the differential voltage, and when the loop of the ALC circuit is turned OFF, a voltage value corresponding to data corresponding to the transmission output frequency is set in the level adjusting unit among the stored data Then, the transmission output level is calibrated.
[0016]
A measuring instrument with a calibration function according to another invention is the measuring instrument with a calibration function according to claim 1,
When a non-modulated signal is input to the level adjustment unit 8 and the loop of the ALC circuit 19 is ON, the comparison unit 13 at each frequency when the transmission output frequency is set to a plurality of designated frequencies. Stored as digital value data of the differential voltage, linearly interpolates data of other frequencies based on the data of the specified frequency, and corresponds to the transmission output frequency of the data when the loop of the ALC circuit is turned OFF. The transmission output level is calibrated by setting a voltage value corresponding to data in the level adjustment unit.
[0017]
A calibration method using a measuring instrument with a calibration function according to another invention is a calibration method using the measuring instrument with a calibration function according to claim 1,
Setting the short-circuit route;
Inputting an unmodulated signal to the level adjusting unit 8;
And a step of measuring the level at each frequency by the level measuring unit 22 while switching the transmission output frequency from the lowest frequency to the highest frequency in predetermined frequency steps.
[0018]
A calibration method using a measuring instrument with a calibration function according to another invention is the calibration method according to claim 4,
Inputting an unmodulated signal to the level adjusting unit 8;
The loop of the ALC circuit 19 is turned ON, and the transmission output frequency is switched from the lowest frequency to the maximum frequency in a predetermined frequency step in this state, and stored as digital value data of the differential voltage of the comparison unit 13 for each frequency; ,
And a step of turning off the loop of the ALC circuit and setting a voltage value corresponding to data corresponding to a transmission output frequency among the stored data in the level adjusting unit.
[0019]
A calibration method using a measuring instrument with a calibration function according to another invention is the calibration method according to claim 4,
Inputting an unmodulated signal to the level adjusting unit 8;
A step of turning on the loop of the ALC circuit 19 and setting the transmission output frequency to a designated frequency at a plurality of points in this state, and storing the data as digital value data of the differential voltage of the comparison unit 13 at each designated frequency;
Linearly interpolating data of other frequencies based on the data of the specified frequency;
And a step of turning off the loop of the ALC circuit and setting a voltage value corresponding to data corresponding to a transmission output frequency among the data in the level adjusting unit.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an outline of the internal configuration of a measuring instrument with a calibration function according to the present invention, FIG. 2 is a flowchart at the time of output level calibration by the measuring instrument with the calibration function, and FIG. 3 is an output level by the measuring instrument with the calibration function. FIG.
[0021]
The measuring device with a calibration function of this example is applied to a measuring device that measures, for example, output power, frequency, modulation accuracy, adjacent channel leakage, modulation bandwidth, reception sensitivity, etc. of a mobile terminal, and a transmission output level. Calibration and reception level calibration.
[0022]
As shown in FIG. 1, the measuring instrument 1 with a calibration function of this example has a divider 2 as a coupler for branching and synthesizing signals. A transmitter 3, a receiver 4 and an antenna 5 are connected to the divider 2. Between the transmission unit 3 and the reception unit 4, a short-circuit route switching unit 6 for passing a signal from the transmission unit 3 directly to the reception unit 4 without passing through the divider 2 is connected in parallel to the divider 2. ing.
[0023]
The transmission unit 3 includes a quadrature modulator 7, a level adjustment unit 8, a transmission-side oscillator 9, a transmission-side mixer 10, an amplifier 11, a level detection unit 12, a comparison unit 13, an A / D conversion unit 14, and a control unit (CPU) 15. , A storage unit 16, a D / A conversion unit 17, and a switching unit 18.
[0024]
The modulation signal output of the quadrature modulator 7 is input to the level adjustment unit 8. The quadrature modulator 7 outputs a non-modulated signal (CW) when calibrating an output level and a reception level, which will be described later.
[0025]
The level adjustment unit 8 is configured by a voltage control type variable attenuator, and an attenuation amount corresponding to the voltage value from the D / A conversion unit 17 or an attenuation amount corresponding to the difference signal (difference voltage) of the comparison unit 13 is set. Is done. The level adjusting unit 8 adjusts the voltage level of the baseband signal from the quadrature modulator 7 by the set attenuation amount. The level-adjusted baseband signal is input to the transmission-side mixer 10.
[0026]
The transmission-side oscillator 9 is composed of a local oscillator that can be varied to an optimum frequency according to the transmission output frequency, and an oscillation signal having a predetermined frequency corresponding to the transmission output frequency is input to the transmission-side mixer 10.
[0027]
The transmission-side mixer 10 mixes the baseband signal whose level is adjusted by the level adjustment unit 8 and the oscillation signal from the transmission-side oscillator 9 and inputs the mixed signal to the amplifier 11.
[0028]
The amplifier 11 amplifies the signal mixed by the transmission side mixer 10 with a predetermined amplification degree and inputs the amplified signal to the divider 2. A signal input to the divider 2 is transmitted from the antenna 5 as a transmission signal to a mobile terminal (DUT) that is a measurement object.
[0029]
The level detection unit 12 detects a signal output from the amplifier 11 and inputs a value corresponding to the detected output level to one input terminal of the comparison unit 13 as a detection voltage value.
[0030]
In the comparison unit 13, the detection signal (detection voltage value) from the level detection unit 12 is input to one input terminal, and the reference voltage is input to the other input terminal. The comparison unit 13 calculates a difference between signals input to both input terminals, and inputs the difference signal (difference voltage) to the A / D conversion unit 14 or the level adjustment unit 8.
[0031]
Here, the reference voltage is set to an appropriate voltage according to the transmission output frequency. When the transmission output frequency is changed, the reference voltage is appropriately variably controlled by the control unit 15 in accordance with the change in the transmission output frequency.
[0032]
The level adjustment unit 8, the transmission-side oscillator 9, the transmission-side mixer 10, the amplifier 11, the level detection unit 12, and the comparison unit 13 change the baseband signal so that the difference signal (difference voltage) of the comparison unit 13 becomes zero. An ALC (Automatic Level Control) circuit 19 that automatically adjusts to a level corresponding to the transmission output frequency is configured.
[0033]
The A / D conversion unit 14 converts the difference signal (difference voltage) from the comparison unit 13 into a digital value and inputs the digital value to the control unit 15.
[0034]
The control unit (CPU) 15 controls each part of the transmission unit 3, the reception unit 4, and the short-circuit route switching unit 6 at the time of measurement and at the time of calibration described later. In addition, the control unit 15 stores the digital value data converted by the A / D conversion unit 14 when the transmission output level is calibrated (including the case where the transmission output level is calibrated when the reception level is calibrated). The information is stored in the unit 16. The storage of the data (digital value) in the storage unit 16 is performed for each transmission output frequency. Further, the control unit 15 outputs a value stored in the storage unit 16 corresponding to the transmission output frequency to the D / A conversion unit 17.
[0035]
The D / A converter 17 converts the digital value output from the controller 15 into an analog voltage value. The converted analog voltage value is set as a set attenuation amount in the level adjustment unit 8 when the switching unit 18 is switched to connect the D / A conversion unit 17 and the level adjustment unit 8. The
[0036]
The switching unit 18 selectively switches whether the output of the comparison unit 13 is connected to the level adjustment unit 8 or the output of the D / A conversion unit 17 is connected to the level adjustment unit 8 under the control of the control unit 15. .
[0037]
In this example, the state in which the contact 18a of the switching unit 18 is switched to the output side of the comparison unit 13, that is, the state in which an ALC loop is formed by the ALC circuit 19, is set to ON. On the other hand, the state in which the contact point 18a of the switching unit 18 is switched to the output side of the D / A conversion unit 17 is OFF.
[0038]
The reception unit 4 includes a reception-side oscillator 20, a reception-side mixer 21, and a level measurement unit 22.
[0039]
The reception-side oscillator 20 is formed of a frequency variable local oscillator similar to the transmission-side oscillator 9. The reception-side oscillator 20 inputs an oscillation signal having the same frequency as that of the transmission-side oscillator 9 to the reception-side mixer 21.
[0040]
The reception-side mixer 21 mixes the signal input from the divider 2 via the antenna 5 or the signal input from the transmission unit 3 via the short-circuit route switching unit 6 and the oscillation signal from the reception-side oscillator 20. This is input to the level measuring unit 22.
[0041]
The level measurement unit 22 measures the level of the signal mixed by the reception-side mixer 21, and uses the measured level as a measurement value.
[0042]
The short-circuit route switching unit 6 is provided with switching units 6B and 6C at both ends of the line 6A. The switching unit 6B is disposed between the amplifier 11 and the divider 2 and the switching unit 6C is configured between the divider 2 and the receiving mixer. 20 between. In the short-circuit route switching unit 6, the contact 6Ba of the switching unit 6B and the contact 6Ca of the switching unit 6C are normally switched to the divider 2 side. On the other hand, when the reception level calibration described later is performed, the control unit 15 switches the contacts 6Ba and 6Ca of the switching units 6B and 6C to the line 6A side.
[0043]
Next, the operation of the measuring instrument 1 with the calibration function configured as described above will be described. Here, description will be made with reference to FIG. 2 and FIG. 3 separately for calibration of the transmission output level and calibration of the reception level.
[0044]
When the transmission output level is calibrated, an unmodulated signal (CW) is first output from the quadrature modulator 7 as shown in FIG. As described above, the unmodulated signal is a sine in which each of the I and Q signals that are input to the quadrature modulator 7 is fixed to a constant DC voltage, or the phase difference between I and Q is +90 or −90 degrees. It is obtained by inputting a wave (ST1). Subsequently, the contact 18a of the switching unit 18 is switched to the comparison unit 13 side, and ALC is turned on (ST2). In this state, the transmission output frequency is sequentially switched from the lowest frequency to the highest frequency in predetermined frequency steps. Then, the level detector 12 detects the output voltage of the amplifier 11 at each frequency that is sequentially switched (ST4). Subsequently, the difference signal between the detection signal of the level detection unit 12 and the reference voltage is A / D converted by the A / D conversion unit 14, and the digital value for each frequency is stored in the storage unit 16 (ST5). When the transmission output frequency is changed, the reference voltage and the frequency of the transmission-side oscillator 9 are also varied according to the frequency. When the transmission output frequency to be actually used is set, the contact 18a of the switching unit 18 is switched to the D / A conversion unit 17 side, and ALC is turned off (ST6). Then, a digital value corresponding to the transmission output frequency is read from the storage unit 16, this digital value is D / A converted by the D / A conversion unit 17, and a voltage value obtained thereby is set in the level adjustment unit 8 (ST7). ). Thereafter, the I and Q signals having the same effective values as those at the time of non-modulation output are input to the quadrature modulator 7 and a modulation signal is output (ST8).
[0045]
The calibration operation described above is an example of an all-frequency calibration mode in which calibration is performed at a predetermined frequency step from the lowest output frequency to the highest output frequency. Specifically, in this all frequency calibration mode, calibration is performed in steps of 10 MHz from the minimum output frequency of 30 MHz to the maximum output frequency of 2.7 GHz.
[0046]
In this example, in addition to the all-frequency calibration mode, a frequency designation calibration mode is prepared. In this frequency designation calibration mode, calibration is performed at output frequencies of a plurality of points arbitrarily designated by the user, for example, frequencies of three points of upper, middle, and lower, and calibration between these three points is performed by linear interpolation. This is the mode to perform. For example, in the case of W-CDMA, calibration is performed with three points of frequency (upper (2.2 GHz), middle (2.05 GHz), and lower (1.9 GHz), and other frequency sections of these output frequencies. Are linearly interpolated. In addition, the frequency designated in this frequency designation calibration mode is not limited to the above three, upper, middle, and lower, and a plurality of frequencies can be designated, and may be at least one.
[0047]
Next, when the reception level is calibrated, the output signal of the quadrature modulator 7 when the ALC is ON is used as a calibration signal. In this example, the transmission output level is corrected together with the reception level. As shown in FIG. 3, first, the contacts 6Ba and 6Ca of the switching units 6B and 6C of the short circuit route switching unit 6 are switched to the line 6A side to set a short circuit route (ST11). Then, the output of the quadrature modulator 7 is converted to a non-modulated signal (ST12). In this state, the transmission output frequency is switched in a predetermined frequency step from the lowest frequency to the highest frequency. Specifically, switching is performed in 10 MHz steps from the lowest output frequency 30 MHz to the highest output frequency 2.2 GHz (ST13). Then, the level measurement unit 22 measures the level at each frequency (ST14).
[0048]
The measured value at each frequency by the level measuring unit 22 is as follows: measured value = raw measured value−short circuit route level measured value + (factory short circuit route level measured value−true level measured value). In the above equation, the raw measurement value is a measurement value of a signal input from the divider 2 via the antenna 5. The short-circuit route level measurement value is a short-circuit route switching unit. This is a measured value when the short-circuit route is set to 6. The short-circuit route level measurement value and the true level measurement value at the time of shipment are stored in advance as calibration data at the time of shipment. The value is an appropriate level measurement value for each frequency in the short circuit route, and the true level measurement value is a measurement value when a specific signal (for example, 0 dB signal) is input from the antenna 5.
[0049]
Thus, according to the measuring instrument with a calibration function and the calibration method of this example, it is possible to output a transmission signal guaranteed with respect to the transmission output frequency actually used. Thereby, the measurement accuracy can be improved. In addition, the measurement time of the entire measurement including calibration can be shortened. For example, in the configuration of the conventional measuring instrument 51 shown in FIG. 4, when the transmission output frequency is changed, it takes 0.5 sec from the start of calibration to the measurement. According to this, calibration can be performed in about 0.2 sec, and the measurement time can be further shortened.
[0050]
Further, the conventional measuring instrument 51 shown in FIG. 4 has a configuration in which the power sensor 69 is built in. However, in this example, the configuration of the power sensor 69 becomes unnecessary and only one divider is required. Can be simplified.
[0051]
【The invention's effect】
As is clear from the above description, according to the present invention, compared with a conventional measuring instrument, the internal calibration of the apparatus can be simplified, and a transmission signal guaranteed for the operating frequency can be output to improve the measurement accuracy. The measurement time of the whole measurement including calibration can be shortened.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of the internal configuration of a measuring instrument with a calibration function according to the present invention. FIG. 2 is a flowchart at the time of output level calibration by the measuring instrument with a calibration function in FIG. Flowchart at the time of calibration of the reception level by the measuring device [FIG. 4] A diagram showing an example of the internal configuration of the conventional measuring device when the output level and the reception level are calibrated. [FIG. Flowchart during calibration [FIG. 6] Flowchart during reception level calibration by the measuring instrument of FIG.
DESCRIPTION OF SYMBOLS 1 ... Measuring device with a calibration function, 2 ... Divider (coupler), 5 ... Antenna, 6 ... Short circuit route switching part, 8 ... Level adjustment part, 12 ... Level detection part, 13 ... Comparison part, 14 ... A / D conversion 15, a control unit (CPU), 17 a D / A conversion unit, 18 a switching unit, 19 an ALC circuit, 22 a level measurement unit.

Claims (6)

A level detection unit (12) that detects an output level of a transmission signal and outputs a value corresponding to the output level as a detection voltage value, and compares the detection voltage value output from the level detection unit with a reference voltage, A comparator (13) that outputs the difference voltage, and a level adjuster (8) that receives the difference voltage output from the comparator and adjusts the output level of the signal with a voltage value corresponding to the difference voltage. An ALC circuit (19);
An A / D conversion section (14) for converting the difference voltage of the comparison section into digital value data and outputting the data;
A controller (15) for holding data from the A / D converter for each transmission output frequency, and outputting data held corresponding to the transmission output frequency;
A D / A converter (17) for outputting the digital value data output from the controller as an analog voltage value;
A switching unit (18) for turning on and off the loop of the ALC circuit so that the differential voltage of the comparison unit or the analog voltage value from the D / A conversion unit is selectively set in the level adjustment unit;
A coupler (2) for outputting a transmission signal from the ALC circuit from an antenna (5) and for branching and combining the signals so as to receive an external signal via the antenna;
A short-circuit route switching unit (6) for selectively switching a route for receiving a signal from the antenna via the coupler and a short-circuit route for allowing the transmission signal to pass without passing through the coupler;
A level measurement unit (22) for measuring the level of an external signal input from the antenna via the coupler or the transmission signal input via the short-circuit route;
When the short-circuit route switching unit is selectively switched to the short-circuit route, an unmodulated signal is input to the level adjustment unit, and the level is adjusted while switching the transmission output frequency from the lowest frequency to the highest frequency in a predetermined frequency step. A measuring instrument with a calibration function, characterized in that a level is measured at each frequency by a measuring unit, and a reception level is calibrated based on the measurement result. When a non-modulated signal is input to the level adjustment unit (8) and the loop of the ALC circuit (19) is ON, the transmission output frequency is switched at a predetermined frequency step from the lowest frequency to the maximum frequency at each frequency. When the ALC circuit loop is turned off, a voltage value corresponding to the data corresponding to the transmission output frequency is stored among the stored data. The measuring device with a calibration function according to claim 1, wherein the transmission output level is calibrated by setting in the level adjustment unit. When a non-modulated signal is input to the level adjustment unit (8) and the loop of the ALC circuit (19) is ON, the transmission output frequency is set to a plurality of designated frequencies. Stored as digital value data of the differential voltage of the comparison unit (13), linearly interpolate data of other frequencies based on the data of the specified frequency, and when the loop of the ALC circuit is turned OFF, 2. The measuring device with a calibration function according to claim 1, wherein a voltage value corresponding to data corresponding to a transmission output frequency is set in the level adjusting unit to calibrate the transmission output level. A calibration method using the measuring instrument with a calibration function according to claim 1,
Setting the short-circuit route;
Inputting an unmodulated signal to the level adjusting unit (8);
Calibration using a measuring instrument with a calibration function, comprising the step of measuring the level at each frequency with the level measuring unit (22) while switching the transmission output frequency from the lowest frequency to the highest frequency in predetermined frequency steps. Method. Inputting an unmodulated signal to the level adjusting unit (8);
The loop of the ALC circuit (19) is turned on, and in this state, the transmission output frequency is switched in a predetermined frequency step from the lowest frequency to the maximum frequency, and as the digital value data of the differential voltage of the comparison unit (13) for each frequency. Memorizing step;
5. The step of turning off the loop of the ALC circuit and setting a voltage value corresponding to data corresponding to a transmission output frequency among the stored data in the level adjustment unit. Calibration method using a measuring instrument with calibration function. Inputting an unmodulated signal to the level adjusting unit (8);
The step of turning on the loop of the ALC circuit (19), setting the transmission output frequency to a designated frequency at a plurality of points in this state, and storing it as digital value data of the differential voltage of the comparison unit (13) at each designated frequency When,
Linearly interpolating data of other frequencies based on the data of the specified frequency;
5. The calibration function according to claim 4, further comprising: turning off the loop of the ALC circuit and setting a voltage value corresponding to data corresponding to a transmission output frequency among the data in the level adjustment unit. Calibration method using a measuring instrument.

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