JP2018100839A - Calibration device and calibration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calibration device which can perform calibration with a simple configuration and with high precision even in calibrating a device having a multiplicity of antenna elements.SOLUTION: A calibration system 1 comprises a reference signal generator 41 which generates a reference signal and outputs it to an up converter 34, a receiving antenna 44 which receives a radio-frequency signal transmitted from each antenna element of an array antenna 38, a down converter 45 which frequency-converts a received signal the receiving antenna 44 receives from each antenna element of the array antenna 38 into a signal to be analyzed having a center frequency lower than a radio-frequency, a calibration unit 48 which calibrates at least one of a power difference and a phase difference between input signals respectively inputted to each antenna element of the array antenna 38 based on the signal to be analyzed frequency-converted by the down converter 45, and an SW group 37 for switching connections between the reference signal generator 41 and each antenna element of the array antenna 38 at a predetermined timing in series.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a calibration device and a calibration method for calibrating a device including an array antenna, for example.

  Conventionally, as this type of device, there is known an array antenna calibration device that simultaneously outputs signals orthogonal to each other to each antenna element to calculate a phase difference between the antenna elements (see, for example, Patent Document 1).

  Patent Document 1 describes a supply means for supplying original calibration signals orthogonal to each antenna element, a calibration signal radiated from each antenna element and received by an antenna element adjacent thereto, and the reception By calculating the correlation with the original calibration signal related to the calibration signal, the phase amplitude characteristic calculating means for obtaining the phase amplitude characteristic of each antenna element, and between all antenna elements based on the phase amplitude characteristic of each antenna element A relative calibration coefficient calculating means for obtaining a relative calibration coefficient; and a calibration means for calibrating a reference signal to be supplied to each antenna element based on the relative calibration coefficient.

  Patent Document 1 describes that this configuration can correct variations in amplitude and phase characteristics including the radiation characteristics of the antenna element without providing a calibration receiving station outside.

JP 2003-218621 A

  However, the conventional device described in Patent Document 1 has a problem that when the number of antenna elements to be calibrated increases, calibration becomes complicated and the accuracy of calibration deteriorates.

  Specifically, the conventional system is configured to calculate the correlation between the calibration signal received by the antenna element and the original calibration signal, so that there are many such as Massive Multi-Input Multi-Output (MIMO). When calibrating a device having a plurality of antenna elements (for example, 256 elements), there is a problem that the calibration becomes complicated.

  Further, in the conventional apparatus, when a device having a large number of antenna elements is calibrated, interference between components that are not completely orthogonal occurs due to a time difference due to a path difference between the antenna elements, and the calibration accuracy deteriorates. There was a problem to do.

  The present invention has been made in order to solve the conventional problems, and provides a calibration apparatus and a calibration method capable of calibrating with high accuracy with a simple configuration even when calibrating a device having a large number of antenna elements. The purpose is to do.

  The calibration apparatus according to claim 1 of the present invention includes an up-converting means (34) for converting a reference signal into a radio frequency signal, and a plurality of antenna elements (38a to 38a) for transmitting the frequency-converted radio frequency signal. c), and a reference signal generating means (41) for generating the reference signal and outputting the reference signal to the up-converting means, and transmitted from each antenna element. A receiving antenna (44) for receiving the signal of the radio frequency, and down-converting means for frequency-converting the received signal received by the receiving antenna from the antenna elements into an analyzed signal having a center frequency lower than the radio frequency ( 45) and each antenna element based on the analyzed signal frequency-converted by the down-conversion means. Calibration means (48) for calibrating at least one of the power difference and phase difference of the input signals to be input, and switching means (37) for sequentially switching the connection between the reference signal generation means and each antenna element at a predetermined timing; It has the structure provided with.

  With this configuration, the calibration apparatus according to claim 1 of the present invention includes switching means for sequentially switching the connection between the reference signal generating means and each antenna element at a predetermined timing, and therefore calibrates an apparatus having a large number of antenna elements. Even in such a case, unlike the conventional case, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration apparatus according to claim 1 of the present invention can calibrate with high accuracy with a simple configuration even when calibrating an apparatus having a large number of antenna elements.

  The calibration apparatus according to claim 2 of the present invention includes a reference signal generation means (21) for generating a reference signal, an up-conversion means (34) for frequency-converting the reference signal to a radio frequency signal, and frequency-converted. A calibration device for calibrating a device under test (10) having a plurality of antenna elements (38a to 38c) for transmitting radio frequency signals, wherein the radio frequency signals transmitted from the antenna elements are A receiving antenna (44) for receiving, a down-converting means (45) for frequency-converting a received signal received by the receiving antenna from each antenna element into an analyzed signal having a center frequency lower than the radio frequency, and the down-converting Power difference and phase of input signals respectively input to the antenna elements based on the signal to be analyzed whose frequency is converted by the means A calibration unit (48) that calibrates at least one of them, and a switching unit (37) that sequentially switches the connection between the reference signal generation unit and each antenna element at a predetermined timing. .

  With this configuration, the calibration device according to claim 2 of the present invention includes the switching unit that sequentially switches the connection between the reference signal generation unit and each antenna element at a predetermined timing, and thus calibrates a device having a large number of antenna elements. Even in such a case, unlike the conventional case, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration apparatus according to claim 2 of the present invention can calibrate with high accuracy with a simple configuration even when calibrating an apparatus having a large number of antenna elements.

  The calibration apparatus according to claim 3 of the present invention is such that the device under test includes an amplifier (35) for amplifying the power of the input signal between the reference signal generating means and each antenna element, and the input signal. The phase shifter (36) for adjusting the phase of the phase shifter (36) is provided.

  With this configuration, the calibration device according to claim 3 of the present invention can calibrate at least one of the amplifier and the phase shifter.

  A calibration apparatus according to a fourth aspect of the present invention includes a plurality of antenna elements (74a to 74c) that receive radio frequency signals, and a signal to be analyzed whose center frequency is lower than the radio frequency. A calibration device for calibrating a device under test (50) having a frequency conversion down-converting means (73), a reference signal generating means (41) for generating a reference signal, and the generated reference signal Up-conversion means (81) for frequency conversion to a radio frequency signal, transmission antenna (82) for transmitting the frequency-converted radio frequency signal, and reception transmitted from the transmission antenna and received by each antenna element An output signal output from each antenna element based on the signal to be analyzed whose frequency is converted by the down-converting means A reception analysis means (47) for analyzing at least one of a power difference and a phase difference; a calibration means (48) for calibrating based on an analysis result of the reception analysis means; and each of the antenna elements and the reception analysis means. And a switching means (37) for sequentially switching the connection at a predetermined timing.

  With this configuration, the calibration apparatus according to claim 4 of the present invention includes switching means for sequentially switching the connection between each antenna element and the calibration means at a predetermined timing, so even when calibrating a device having a large number of antenna elements. Thus, unlike conventional ones, calibration does not become complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration device according to claim 4 of the present invention can calibrate with high accuracy with a simple configuration even when calibrating a device having a large number of antenna elements.

  A calibration apparatus according to claim 5 of the present invention includes a plurality of antenna elements (74a to 74c) that receive a radio frequency signal, and a signal to be analyzed whose center frequency is lower than the radio frequency of the received radio frequency signal. A calibration device for calibrating a device under test (50) having a frequency conversion down-converting means (73), a reference signal generating means (41) for generating a reference signal, and the generated reference signal An up-conversion means (81) for frequency conversion to a radio frequency signal; and a transmission antenna (82) for transmitting the frequency-converted radio frequency signal, wherein the device under test is transmitted from the transmission antenna. The received signal received by each antenna element is transmitted from each antenna element based on the analyzed signal obtained by frequency-converting the received signal by the down-converting means. Reception analysis means (62) for analyzing at least one of the power difference and phase difference of the output signals output from each output; and calibration means (63) for calibrating based on the analysis result of the reception analysis means. And a switching means (37) for sequentially switching the connection between each antenna element and the reception analyzing means at a predetermined timing.

  With this configuration, the calibration device according to claim 5 of the present invention includes switching means for sequentially switching the connection between each antenna element and the calibration means at a predetermined timing, so even when a device having a large number of antenna elements is calibrated. Thus, unlike conventional ones, calibration does not become complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration apparatus according to claim 5 of the present invention can calibrate with high accuracy with a simple configuration even when calibrating an apparatus having a large number of antenna elements.

  In the calibration device according to claim 6 of the present invention, the device under test includes an amplifier (35) for amplifying the power of the output signal between each antenna element and the reception analysis means, and the output signal. It has a configuration including at least one of a phase shifter (36) for adjusting the phase.

  With this configuration, the calibration device according to claim 6 of the present invention can calibrate the device under measurement by adjusting at least one of the amplifier and the phase shifter to a desired value.

  The calibration apparatus according to claim 7 of the present invention has a configuration in which the reference signal generating means generates a reference signal having a bandwidth that is equal to or greater than a bandwidth that the antenna elements can handle.

  With this configuration, the calibration device according to claim 7 of the present invention can acquire a broadband calibration value at a time.

  The calibration method according to claim 8 of the present invention includes an up-conversion means (34) for converting a reference signal into a radio frequency signal, and a plurality of antenna elements (38a to 38a) for transmitting the frequency-converted radio frequency signal. a calibration method using the calibration device according to claim 1, wherein the reference signal is generated and output to the up-converting means (c). S13), a reception step (S17) for receiving the radio frequency signal transmitted from each antenna element, and a reception signal received from each antenna element in the reception step has a center frequency lower than the radio frequency A down-conversion step (S18) for converting the frequency to the signal to be analyzed, and the frequency conversion in the down-conversion step. A calibration step (S20) for calibrating at least one of a power difference and a phase difference of input signals respectively input to the antenna elements based on the analyzed signal; and the reference signal generating means and the antenna elements And a switching step (S15) for sequentially switching connections at a predetermined timing.

  With this configuration, the calibration method according to claim 8 of the present invention sequentially switches the connection between the reference signal generating means and each antenna element at a predetermined timing, so that even when a device having a large number of antenna elements is calibrated, Thus, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration apparatus according to claim 8 of the present invention can calibrate with high accuracy with a simple configuration even when calibrating an apparatus having a large number of antenna elements.

  A calibration method according to claim 9 of the present invention includes a plurality of antenna elements (74a to 74c) that receive a radio frequency signal, and a signal to be analyzed whose center frequency is lower than the radio frequency of the received radio frequency signal. 5. A calibration method using the calibration device according to claim 4, wherein the device to be measured is calibrated with a down-converting means (73) for frequency conversion to a reference signal generating step (S13) for generating a reference signal. An up-conversion step (S32) for frequency-converting the generated reference signal into a radio frequency signal, a transmission step (S33) for transmitting the frequency-converted radio frequency signal, and transmission from the transmission antenna. A down-conversion step (S18) for frequency-converting a received signal received by each antenna element into the signal to be analyzed; A reception analysis step (S19) for analyzing at least one of a power difference and a phase difference of output signals respectively output from the antenna elements based on the signal to be analyzed frequency-converted in a step, and the reception analysis step A calibration step (S20) for calibrating based on the analysis result of (2), and a switching step (S15) for sequentially switching the connection between each antenna element and the reception analysis means at a predetermined timing.

  With this configuration, the calibration method according to claim 9 of the present invention sequentially switches the connection between each antenna element and the calibration means at a predetermined timing. Therefore, even when a device having a large number of antenna elements is calibrated, Thus, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration device according to claim 9 of the present invention can calibrate with high accuracy with a simple configuration even when a device having a large number of antenna elements is calibrated.

  The present invention can provide a calibration device and a calibration method that have the effect of being able to calibrate with high accuracy with a simple configuration even when a device having a large number of antenna elements is calibrated.

It is a block block diagram in 1st Embodiment of the calibration apparatus which concerns on this invention. It is a flowchart in 1st Embodiment of the calibration apparatus which concerns on this invention. It is a block block diagram in 2nd Embodiment of the calibration apparatus which concerns on this invention. It is a flowchart in 2nd Embodiment of the calibration apparatus which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A calibration system provided with the calibration apparatus of the present invention will be described as an example.

(First embodiment)
First, the configuration of the calibration system according to the first embodiment of the present invention will be described.

  As shown in FIG. 1, a calibration system 1 according to the present embodiment includes a base station 10 as a device to be calibrated, a measurement device 40 that performs measurement for calibrating transmission characteristics of the base station 10, It has.

  The base station 10 includes a main board 20 and an RF / ANT board 30.

  The main board 20 includes a reference signal generator 21, a DAC (digital / analog converter) 22, and a SW (switch) switching unit 23.

  The RF / ANT board 30 includes switching SWs 31 and 32, a SW switching unit 33, a UC (upconverter) 34, an amplifier group 35, a phase shifter group 36, a SW group 37, and an array antenna 38.

  The measuring device 40 includes a reference signal generator 41, a DAC 42, an SW switching unit 43, a reception antenna 44, a DC (down converter) 45, an ADC (analog / digital converter) 46, a reception analysis unit 47, and a calibration unit 48. .

  The calibration system 1 in the present embodiment is a mode for calibrating the RF / ANT board 30 in the base station 10 using a reference signal (described later) from the reference signal generator 41 of the measuring apparatus 40 (hereinafter simply referred to as “ANT board calibration”). Mode) and a mode in which the entire base station 10 is calibrated using a reference signal (described later) from the reference signal generator 21 in the main board 20 of the base station 10 (hereinafter simply referred to as “base station calibration mode”). And having. Hereinafter, a detailed configuration of the calibration system 1 will be described.

  First, the configuration of the main board 20 of the base station 10 will be described.

  The reference signal generator 21 can generate a baseband signal for calibration, and generates a reference signal having a bandwidth that is equal to or greater than the bandwidth that can be handled by each antenna element included in the array antenna 38. This reference signal is a broadband modulated wave signal such as a signal used in an OFDM communication system, for example. The reference signal is specifically a signal with known power and phase, such as a pilot signal used in an OFDM communication system, for example. By using this type of reference signal, the calibration system 1 in the present embodiment can acquire a broadband calibration value in a short time at a time.

  More specifically, if the frequencies that can be handled by each antenna element are, for example, a millimeter wave band with a center frequency of 28 GHz and a bandwidth of 1 GHz, the reference signal generator 21 has a bandwidth of 27.5 GHz to 28.5 GHz or more. A wide-band reference signal having a bandwidth of 1 is generated. The reference signal generator 21 is an example of a reference signal generation unit in the base station calibration mode.

  In the conventional method, when a wideband signal such as a bandwidth of 1 GHz is calibrated, it is necessary to obtain a calibration value for a number of frequencies in consideration of the frequency characteristics within the bandwidth. It took time. On the other hand, in the present embodiment, since the broadband reference signal as described above is used, a broadband calibration value can be acquired at a short time, and the calibration can be shortened.

  The DAC 22 converts the modulated reference signal generated by the reference signal generator 21 from a digital value to an analog value, and outputs the analog value to the RF / ANT board 30.

  The SW switching unit 23 outputs a control signal to the SW group 37 of the RF / ANT board 30 via the switching SW 32 of the RF / ANT board 30, and sequentially switches each SW included in the SW group 37 at a predetermined timing. It has become. For example, when the base station 10 operates in the OFDM communication system, the SW switching unit 23 sets predetermined data such as every frame, every subframe, or every symbol. It is preferable to switch at a switching time interval for each unit. The SW switching unit 23 performs control for sequentially switching the SWs to be turned on by turning on only one SW in the SW group 37 and turning off the other SWs.

  Next, the configuration of the RF / ANT board 30 of the base station 10 will be described.

  The switching SW 31 is configured to connect the DAC 22 or the DAC 42 and the UC 34 based on a control signal from the SW switching unit 33.

  The switching SW 32 is configured to connect the SW switching unit 23 or the SW switching unit 43 and the SW group 37 based on a control signal from the SW switching unit 33.

  The SW switching unit 33 controls the switching operation of the switching SW 31 and the switching SW 32.

  Specifically, the SW switching unit 33 outputs a control signal to the switching SW 31 so as to connect the DAC 42 and the UC 34 of the measuring device 40 in the ANT board calibration mode, and the SW switching unit 43 and the SW group of the measuring device 40. A control signal is output to the switching SW 32 so as to connect to the switch 37. In addition, in the base station calibration mode, the SW switching unit 33 outputs a control signal to the switching SW 31 so as to connect the DAC 22 and the UC 34 of the main board 20, and switches the SW switching unit 23 and the SW group 37 of the main board 20. A control signal is output to the switching SW 32 so as to be connected.

  The UC 34 converts the reference signal input from the DAC 22 or the DAC 42 into a signal of a predetermined radio frequency, distributes the frequency-converted signal to each amplifier included in the amplifier group 35, and outputs the signal.

  The amplifier group 35 includes a plurality of amplifiers that amplify the power of the input signal. The amplifier group 35 includes amplifiers 35a to 35c. The amplification factor of each amplifier included in the amplifier group 35 can be set to a predetermined value by the calibration unit 48.

  The phase shifter group 36 includes a plurality of phase shifters that adjust the phase of the input signal. The phase shifter group 36 includes phase shifters 36a to 36c. The phase adjustment value of each phase shifter included in the phase shifter group 36 can be set to a predetermined value by the calibration unit 48.

  The SW group 37 includes a plurality of SWs that sequentially switch the path between the phase shifter group 36 and the plurality of antenna elements at a predetermined timing based on a control signal from the SW switching unit 23 or the SW switching unit 43. The SW group 37 is configured to sequentially switch the path between the reference signal generator 21 or 41 and each antenna at a predetermined timing. The SW group 37 includes SWs 37a to 37c. For example, the SW switching unit 23 first turns on only the SW 37a and turns off all other SWs, then turns on only the SW 37b, turns off all other SWs, and then turns on only the SW 37c. The switch is controlled such that is on and all other SWs are off. The SW group 37 is an example of a switching unit.

  The array antenna 38 includes a plurality of antenna elements. Each antenna element is constituted by a planar antenna such as a microstrip antenna, for example, and transmits a radio frequency signal (radio wave) to the receiving antenna 44. Array antenna 38 includes antenna elements 38a-38c.

  Next, the configuration of the measuring device 40 will be described.

  Similar to the reference signal generator 21 described above, the reference signal generator 41 generates a wideband reference signal having a bandwidth that is greater than or equal to the bandwidth that can be accommodated by each antenna element included in the array antenna 38. . The reference signal generator 41 is an example of a reference signal generating unit in the ANT board calibration mode.

  The DAC 42 converts the reference signal of the modulated wave generated by the reference signal generator 41 from a digital value to an analog value and outputs it to the RF / ANT board 30.

  Similar to the SW switching unit 23 described above, the SW switching unit 43 outputs a control signal to the SW group 37 of the RF / ANT board 30 via the switching SW 32, and sets each SW included in the SW group 37 at a predetermined timing. It is designed to switch sequentially.

  The timing at which the SW switching unit 43 switches each SW is shared with the base station 10 side. For example, the trigger timing at the start and the clock are shared between the base station 10 side and the measuring apparatus 40 side so that the antenna elements used for transmission are switched at a predetermined timing. Also, for example, a means for exchanging control signals for switching timing between the base station 10 side and the measurement apparatus 40 side is provided, and an antenna element that transmits a radio wave including a reference signal is designated from the measurement apparatus 40 to the base station 10. The base station 10 can determine the antenna element that transmits the radio wave including the reference signal or the reference signal, and can notify the measurement device 40.

  The receiving antenna 44 receives a radio frequency signal (radio wave) transmitted from each antenna element of the array antenna 38 and outputs it to the DC 45. As described above, since the antenna elements of the array antenna 38 are sequentially switched at a predetermined timing by the SW switching unit 23 or 43, the reception antenna 44 sequentially receives the transmission signals of the respective antenna elements at the predetermined timing.

  The DC 45 is configured to frequency-convert the reception signal sequentially received from each antenna element by the reception antenna 44 into a baseband signal and output it to the ADC 46. The DC 45 is an example of down-conversion means.

  The ADC 46 converts the signal frequency-converted by the DC 45 from an analog value to a digital value and outputs the converted signal to the reception analysis unit 47.

  The reception analysis unit 47 analyzes a baseband signal output from the DC 45. Specifically, the reception analysis unit 47 uses the SW switching unit 23 or 43 to sequentially switch the antenna elements of the array antenna 38 at a predetermined timing, with respect to the signal after the frequency conversion from the antenna elements of the array antenna 38. Find the phase. The reception analysis unit 47 constitutes a reception analysis unit.

  Further, the reception analysis unit 47 obtains a power difference with respect to a predetermined power reference value for each antenna element of the array antenna 38. Further, the reception analysis unit 47 obtains a phase difference with respect to the reference phase for each antenna element of the array antenna 38 using the phase of one predetermined antenna element as a reference phase. The reception analysis unit 47 analyzes data in a range where the data is not affected by switching of the SW group 37 of the RF / ANT board 30.

  The calibration unit 48 calibrates the power difference and phase difference of the input signals respectively input to the antenna elements based on the baseband signal frequency-converted by the DC 45. Specifically, the calibration unit 48 sequentially inputs the power of a signal sequentially input to each antenna element with respect to the power reference value within a predetermined tolerance, and is sequentially input to each antenna element with respect to the reference phase. The power and phase of each antenna element are calibrated so that the signal phase falls within a predetermined tolerance. The calibration unit 48 is an example of a calibration unit.

  In the above-described configuration, the reference signal generator 21 or 41, the receiving antenna 44, the DC 45, the calibration unit 48, and the SW group 37 constitute a calibration device according to the present invention.

  In the present embodiment, the calibration unit 48 calibrates both the power difference and the phase difference of the input signal. However, the calibration unit 48 may calibrate at least one of the power difference and the phase difference of the input signal. Good.

  Next, operation | movement of the calibration system 1 in this embodiment is demonstrated using FIG.

  Initial setting is performed by the user operating the operation units (not shown) of the base station 10 and the measurement apparatus 40 (step S11).

  As an initial setting, a mode setting for specifying either the ANT board calibration mode or the base station calibration mode, a setting of a baseband reference signal to be generated by the reference signal generator 21 or 41, an amplifier group 35 and a phase shifter group 36. There is a setting of the initial value. Note that all SWs included in the SW group 37 are set to OFF in the initial state.

  In the mode setting, the following description will be made assuming that the ANT board calibration mode is set.

  The SW switching unit 33 sets the input side of the switching SW 31 to the DAC 42 side of the measuring device 40 and sets the input side of the switching SW 32 to the SW switching unit 43 side of the measuring device 40 (step S12).

  The reference signal generator 41 generates a baseband reference signal set in the initial setting (step S13) and outputs it to the DAC. The DAC 42 converts the input reference signal from a digital value to an analog value, and outputs it to the UC 34 via the switch SW31.

  The UC 34 converts the input analog value reference signal into a signal of a predetermined radio frequency (step S14), distributes the frequency-converted signal to each amplifier included in the amplifier group 35, and outputs it.

  The amplifier group 35 amplifies the power of the input signal with a preset amplification factor and outputs the amplified signal to the phase shifter group 36. The phase shifter group 36 adjusts the phase of the input signal to a preset phase and outputs it to the SW group 37.

  The SW group 37 sequentially switches each SW at a predetermined timing based on the control signal from the SW switching unit 43 (step S15). Specifically, first, the SW group 37 switches only the SW 37a from off to on, and turns off after a predetermined time. Next, the SW group 37 switches only the SW 37b from off to on, and turns off after a predetermined time. Subsequently, the SW group 37 switches only the SW 37c from off to on, and turns off after a predetermined time.

  The array antenna 38 sequentially transmits radio frequency signals (radio waves) at predetermined timings from the antenna elements 38a, 38b, 38c,... According to the switching operation of the SW group 37 (step S16).

  The receiving antenna 44 sequentially receives radio frequency signals transmitted from the array antenna 38 (step S17) and outputs them to the DC 45.

  The DC 45 frequency-converts the reception signals received sequentially from the antenna elements by the reception antenna 44 into baseband signals (step S18), and outputs them to the ADC 46. The ADC 46 converts the signal frequency-converted by the DC 45 from an analog value to a digital value, and outputs it to the reception analysis unit 47.

  The reception analysis unit 47 analyzes the baseband signal output from the DC 45 (step S19), and obtains a power difference with respect to a predetermined power reference value for each antenna element. In addition, the reception analysis unit 47 uses a predetermined phase of one antenna element as a reference phase, and obtains a phase difference with respect to the reference phase for each antenna element.

  The calibration unit 48 is configured so that the power of the input signal sequentially input to each antenna element with respect to the power reference value is within a predetermined tolerance, and the input signal sequentially input to each antenna element with respect to the reference phase. The power and phase of each antenna element are calibrated so that the phase falls within a predetermined tolerance (step S20).

  In the base station calibration mode, the SW switching unit 23, the reference signal generator 21, and the DAC 22 execute each process in place of the SW switching unit 43, the reference signal generator 41, and the DAC 42, respectively.

  As described above, the calibration system 1 according to this embodiment includes the SW group 37 that sequentially switches the connection between the reference signal generator 21 or 41 and each antenna element of the array antenna 38 at a predetermined timing. Even when a device having the antenna element is calibrated, unlike conventional ones, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals.

  Therefore, the calibration system 1 in this embodiment can calibrate with high accuracy with a simple configuration even when calibrating a device having a large number of antenna elements.

  In the above-described embodiment, the base station has been described as an example of the device to be measured. However, the present invention is not limited to this, and the same applies to, for example, a terminal device that communicates using the OFDM communication method. An effect is obtained.

  In the above-described embodiment, the path from the reference signal generator 21 to the array antenna 38 is described as one path. However, the present invention is not limited to this, and the path is divided into a plurality of parallel paths. It is good also as a structure.

(Second Embodiment)
First, the configuration of the calibration system according to the second embodiment of the present invention will be described.

  As shown in FIG. 3, the calibration system 2 in the present embodiment includes a base station 50 as a device to be calibrated as a calibration target, a measurement device 80 that performs measurement for calibrating the reception characteristics of the base station 50, It has. In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment (refer FIG. 1), and description of the overlapping structure is abbreviate | omitted.

  The base station 50 includes a main board 60 and an RF / ANT board 70.

  The main board 60 includes a SW switching unit 23, an ADC 61, a reception analysis unit 62, and a calibration unit 63.

  The RF / ANT board 70 includes switching SWs 31, 32 and 71, SW switching unit 72, DC 73, array antenna 74, adder 75, amplifier group 35, phase shifter group 36, and SW group 37.

  The measurement device 80 includes a reference signal generator 41, a DAC 42, a UC 81, a transmission antenna 82, a SW switching unit 43, an ADC 46, a reception analysis unit 47, and a calibration unit 48. The reception analysis unit 47 in this embodiment is an example of a reception analysis unit.

  The calibration system 2 in the present embodiment includes an ANT board calibration mode in which the RF / ANT board 70 in the base station 50 is calibrated using the calibration unit 48 of the measuring device 80, and a calibration unit 63 in the main board 60 of the base station 50. And a base station calibration mode for calibrating the entire base station 50. Hereinafter, a detailed configuration of the calibration system 2 will be described.

  First, the configuration of the main board 60 of the base station 50 will be described.

  The ADC 61 converts the signal frequency-converted by the DC 73 from an analog value to a digital value and outputs the converted signal to the reception analysis unit 62.

  The reception analysis unit 62 analyzes a baseband signal output from the ADC 61. Specifically, the reception analysis unit 62 performs frequency conversion on the received signal output from the antenna element of the array antenna 74 as the antenna element of the array antenna 74 is sequentially switched at a predetermined timing by the SW switching unit 23. Find power and phase. Further, the reception analysis unit 62 obtains a power difference with respect to a predetermined power reference value for each antenna element. In addition, the reception analysis unit 62 uses a predetermined phase of one antenna element as a reference phase, and obtains a phase difference with respect to the reference phase for each antenna element. The reception analysis unit 62 is an example of a reception analysis unit.

  The calibration unit 63 calibrates the power difference and phase difference of the output signals output from each antenna element of the RF / ANT board 70 based on the baseband signal frequency-converted by the DC 73 of the RF / ANT board 70. It has become. Specifically, the calibration unit 63 sequentially outputs the power of the output signal sequentially output from each antenna element with respect to the power reference value within a predetermined tolerance, and sequentially outputs from each antenna element with respect to the reference phase. The power and phase of each antenna element are calibrated so that the phase of the output signal is within a predetermined tolerance. The calibration unit 63 is an example of a calibration unit.

  Next, the configuration of the RF / ANT board 70 of the base station 50 will be described.

  The switching SW 71 connects the calibration unit 48 or 63, the amplifier group 35, and the phase shifter group 36 based on a control signal from the SW switching unit 72.

  The SW switching unit 72 controls the switching operation of the switching SWs 31, 32, and 71.

  Specifically, the SW switching unit 72 outputs a control signal to the switching SW 71 so as to connect the calibration unit 48 of the measuring device 80 to the amplifier group 35 and the phase shifter group 36 in the ANT board calibration mode. ing. Further, the SW switching unit 72 outputs a control signal to the switching SW 71 so as to connect the calibration unit 63 of the main board 60, the amplifier group 35, and the phase shifter group 36 in the base station calibration mode.

  The adder 75 adds the radio frequency signals input from the amplifier group 35 and outputs the result to the DC 73.

  The DC 73 frequency-converts the radio frequency signal input from the adder 75 into a baseband signal and outputs the frequency-converted signal to the switch SW31.

  The array antenna 74 includes a plurality of antenna elements, and receives radio frequency signals (radio waves) from the transmission antenna 82. Array antenna 74 includes antenna elements 74a-74c. The radio frequency signal received by the array antenna 74 is input to the DC 73 via the SW group 37, the phase shifter group 36, the amplifier group 35, and the adder 75 in order.

  Next, the configuration of the measuring device 80 will be described.

  The UC 81 converts the reference signal input from the DAC 42 into a signal having a predetermined radio frequency, and outputs the frequency-converted signal to the transmission antenna 82.

  The transmission antenna 82 transmits a radio frequency signal (radio wave) to the array antenna 74.

  In the above-described configuration, the reference signal generator 41, the UC 81, the transmission antenna 82, the calibration unit 48 or 63, and the SW group 37 constitute a calibration device according to the present invention.

  In the present embodiment, the calibration units 48 and 63 calibrate both the power difference and phase difference of the input signal, but calibrate at least one of the power difference and phase difference of the input signal. May be.

  Next, operation | movement of the calibration system 2 in this embodiment is demonstrated using FIG.

  Initial setting is performed by the user operating the operation units (not shown) of the base station 50 and the measuring apparatus 80 (step S11).

  In the mode setting, the following description will be made assuming that the ANT board calibration mode is set.

  The SW switching unit 72 has the output side of the switching SW 31 on the ADC 46 side of the measuring device 80, the input side of the switching SW 32 on the SW switching unit 43 side of the measuring device 80, and the input side of the switching SW 71 on the calibration unit 48 of the measuring device 80. Are set respectively on the side (step S31).

  The reference signal generator 41 generates a baseband reference signal set in the initial setting (step S13) and outputs it to the DAC. The DAC 42 converts the input reference signal from a digital value to an analog value and outputs it to the UC 81.

  The UC 81 frequency-converts the input analog baseband signal to a signal of a predetermined radio frequency (step S32), and outputs the frequency-converted signal to the transmission antenna 82.

  The transmission antenna 82 transmits a radio frequency signal (radio wave) output from the UC 81 (step S33).

  The array antenna 74 receives a radio frequency signal (radio wave) from the transmission antenna 82 (step S34).

  The SW group 37 sequentially switches each SW at a predetermined timing based on the control signal from the SW switching unit 43 (step S15), and outputs it to the phase shifter group 36. The phase shifter group 36 sequentially adjusts the phase of the input signal to a preset phase and outputs it to the amplifier group 35. The amplifier group 35 sequentially amplifies the power of the input signal with a preset amplification factor and outputs the amplified signal to the adder 75. The adder 75 adds the radio frequency signals input from the amplifier group 35 and outputs the result to the DC 73.

  The DC 73 frequency-converts the signal from the adder 75 into a baseband signal (step S18), and outputs it to the ADC 46. The ADC 46 converts the signal frequency-converted by the DC 73 from an analog value to a digital value, and outputs it to the reception analysis unit 47.

  The reception analysis unit 47 analyzes the baseband signal output from the ADC 46 (step S19), and obtains a power difference with respect to a predetermined power reference value for each antenna element. In addition, the reception analysis unit 47 uses a predetermined phase of one antenna element as a reference phase, and obtains a phase difference with respect to the reference phase for each antenna element.

  The calibration unit 48 ensures that the power of the output signal sequentially output from each antenna element with respect to the power reference value falls within a predetermined tolerance, and the output signal sequentially output from each antenna element with respect to the reference phase. The power and phase of each antenna element are calibrated so that the phase falls within a predetermined tolerance (step S20).

  In the base station calibration mode, the SW switching unit 23, the ADC 61, the reception analysis unit 62, and the calibration unit 63 perform the processes in place of the SW switching unit 43, the ADC 46, the reception analysis unit 47, and the calibration unit 48, respectively. Run.

  As described above, the calibration system 2 in the present embodiment is configured to include the SW group 37 that sequentially switches the connection between each antenna element of the array antenna 74 and the reception analysis unit 47 or 62 at a predetermined timing. Even when a device having an element is calibrated, calibration is not complicated, and interference between components that are not completely orthogonal does not occur between calibration signals, unlike the conventional apparatus.

  Therefore, the calibration system 2 in the present embodiment can calibrate with high accuracy with a simple configuration even when a device having a large number of antenna elements is calibrated.

  In the above-described embodiment, the base station has been described as an example of the device to be measured. However, the present invention is not limited to this, and the same applies to, for example, a terminal device that communicates using the OFDM communication method. An effect is obtained.

  In the above-described embodiment, the route from the array antenna 74 to the reception analysis unit 62 has been described as one route. However, the present invention is not limited to this, and the route is divided into a plurality of parallel routes. It is good also as a structure.

  As described above, the calibration device and the calibration method according to the present invention have the effect that even when a device having a large number of antenna elements is calibrated, the calibration can be performed with high accuracy with a simple configuration. The present invention is useful as a calibration device and a calibration method for calibrating a provided device.

1, 2, Calibration system 10, 50 Base station (device under test)
21, 41 Reference signal generator (reference signal generating means)
34 UC (up-conversion means)
35 amplifier group 35a-35c amplifier 36 phase shifter group 36a-36c phase shifter 37 SW group (switching means)
37a-37c SW
38, 74 Array antennas 38a-38c, 74a-74c Plural antenna elements 40, 80 Measuring device 44 Receiving antenna 45, 73 DC (down-converting means)
47, 62 Reception analysis unit (reception analysis means)
48, 63 Calibration section (calibration means)
81 UC (up-conversion means)
82 Transmitting antenna

Claims (9)

A device under test (10) having up-conversion means (34) for converting a reference signal into a radio frequency signal and a plurality of antenna elements (38a to 38c) for transmitting the frequency-converted radio frequency signal. A calibration device for calibrating
Reference signal generation means (41) for generating the reference signal and outputting it to the up-conversion means;
A receiving antenna (44) for receiving the radio frequency signal transmitted from each antenna element;
Down-converting means (45) for frequency-converting the received signal received by the receiving antenna from each antenna element into an analyzed signal having a center frequency lower than the radio frequency;
Calibration means (48) for calibrating at least one of a power difference and a phase difference of input signals respectively input to the antenna elements based on the signal to be analyzed that has been frequency-converted by the down-conversion means;
Switching means (37) for sequentially switching the connection between the reference signal generating means and each antenna element at a predetermined timing;
A calibration apparatus comprising: Reference signal generating means (21) for generating a reference signal, up-converting means (34) for converting the reference signal into a radio frequency signal, and a plurality of antenna elements for transmitting the frequency-converted radio frequency signal (38a-c), a calibration device for calibrating the device under measurement (10),
A receiving antenna (44) for receiving the radio frequency signal transmitted from each antenna element;
Down-converting means (45) for frequency-converting the received signal received by the receiving antenna from each antenna element into an analyzed signal having a center frequency lower than the radio frequency;
Calibration means (48) for calibrating at least one of a power difference and a phase difference of input signals respectively input to the antenna elements based on the signal to be analyzed that has been frequency-converted by the down-conversion means;
Switching means (37) for sequentially switching the connection between the reference signal generating means and each antenna element at a predetermined timing;
A calibration apparatus comprising:   The device under test includes an amplifier (35) for amplifying the power of the input signal and a phase shifter (36) for adjusting the phase of the input signal between the reference signal generating means and each antenna element. The calibration device according to claim 1, wherein at least one of the calibration devices is provided. A plurality of antenna elements (74a-c) for receiving radio frequency signals; and down-converting means (73) for frequency-converting the received radio frequency signals into an analyzed signal having a center frequency lower than the radio frequency; A calibration device for calibrating a device under test (50) having:
Reference signal generating means (41) for generating a reference signal;
Up-conversion means (81) for frequency-converting the generated reference signal into a radio frequency signal;
A transmitting antenna (82) for transmitting the frequency-converted radio frequency signal;
A power difference and a phase difference of output signals respectively output from the antenna elements based on the analyzed signals transmitted from the transmitting antenna and received by the antenna elements and frequency-converted by the down-conversion means. Receiving analysis means (47) for analyzing at least one of
Calibration means (48) for calibrating based on the analysis result of the reception analysis means;
Switching means (37) for sequentially switching the connection between each antenna element and the reception analysis means at a predetermined timing;
A calibration apparatus comprising: A plurality of antenna elements (74a-c) for receiving radio frequency signals; and down-converting means (73) for frequency-converting the received radio frequency signals into an analyzed signal having a center frequency lower than the radio frequency; A calibration device for calibrating a device under test (50) having:
Reference signal generating means (41) for generating a reference signal;
Up-conversion means (81) for frequency-converting the generated reference signal into a radio frequency signal;
A transmitting antenna (82) for transmitting the frequency-converted radio frequency signal;
With
The device under test is
A power difference and a phase difference of output signals respectively output from the antenna elements based on the analyzed signals transmitted from the transmitting antenna and received by the antenna elements and frequency-converted by the down-conversion means. Receiving analysis means (62) for analyzing at least one of
Calibration means (63) for calibrating based on the analysis result of the reception analysis means;
With
A calibration apparatus comprising switching means (37) for sequentially switching the connection between each antenna element and the reception analysis means at a predetermined timing.   The device under test includes an amplifier (35) that amplifies the power of the output signal and a phase shifter (36) that adjusts the phase of the output signal between each antenna element and the reception analysis means. 6. The calibration apparatus according to claim 4, wherein at least one of them is provided.   7. The reference signal generation unit according to claim 1, wherein the reference signal generation unit generates a reference signal having a bandwidth that is equal to or greater than a bandwidth that can be handled by each antenna element. 8. The calibration device described. A device under test (10) having up-conversion means (34) for converting a reference signal into a radio frequency signal and a plurality of antenna elements (38a to 38c) for transmitting the frequency-converted radio frequency signal. A calibration method using the calibration device according to claim 1, wherein
A reference signal generation step (S13) for generating the reference signal and outputting it to the up-conversion means;
A receiving step (S17) of receiving the radio frequency signal transmitted from each antenna element;
A down-conversion step (S18) for frequency-converting the reception signal received from each antenna element in the reception step into an analyzed signal having a center frequency lower than the radio frequency;
A calibration step (S20) for calibrating at least one of a power difference and a phase difference of input signals respectively input to the antenna elements based on the signal to be analyzed whose frequency is converted in the down-conversion step;
A switching step (S15) for sequentially switching the connection between the reference signal generating means and each antenna element at a predetermined timing;
A calibration method comprising: A plurality of antenna elements (74a-c) for receiving radio frequency signals; and a down-convert means (73) for converting the received radio frequency signals into an analyzed signal having a center frequency lower than the radio frequency; A calibration method using the calibration device according to claim 4, wherein the device under test is calibrated.
A reference signal generation step (S13) for generating a reference signal;
An up-conversion step (S32) for frequency-converting the generated reference signal into a radio frequency signal;
A transmission step (S33) for transmitting the frequency-converted radio frequency signal;
A down-conversion step (S18) for frequency-converting a received signal transmitted from the transmitting antenna and received by each antenna element into the analyzed signal;
A reception analysis step (S19) for analyzing at least one of a power difference and a phase difference of the output signals respectively output from the antenna elements based on the signal to be analyzed that is frequency-converted in the down-conversion step;
A calibration step (S20) for calibrating based on the analysis result of the reception analysis step;
A switching step (S15) for sequentially switching the connection between each antenna element and the reception analysis means at a predetermined timing;
A calibration method comprising:

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