Measuring device and its measurement method

Abstract

To provide a measuring apparatus capable of suppressing noise during an EVM measurement when a level of an input signal changes.SOLUTION: A measuring apparatus includes: a first input port 31; a first variable attenuator 32 that attenuates a signal level of an Uplink signal input to the first input port 31 in accordance with a set input level; a first AD converter 33 that converts an analog signal attenuated by the first variable attenuator 32 into a digital signal; a signal analysis part 4 that performs modulation analysis of a section in which the digital signal output from the first AD converter 33 is to be measured; and a control part 7 that changes the input level in accordance with the section to be measured at the time of measuring each section in a case of performing measurement of an input signal having a plurality of sections with different signal levels.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a measuring device that measures radio waves transmitted by a wireless terminal in a mobile communication system.

Background Art

[0002] Regarding wireless terminals that transmit and receive wireless signals corresponding to IEEE802.11ad, 5G cellular, etc. that use broadband signals in the millimeter wave band, which have been developed in recent years, for the antennas for wireless communication provided in the wireless terminals, performance tests are conducted to measure the output level and reception sensitivity of the transmitted radio waves defined for each communication standard and to determine whether a predetermined standard is satisfied.

[0003] One such measurement item is EVM (Error Vector Magnitude). EVM indicates the deviation between the measured signal and the theoretically modulated signal of a signal to which digital modulation is applied.

[0004] Patent Document 1 describes estimating the characteristics of phase error using only signal data corresponding to symbols having an EVM smaller than a predetermined reference value and correcting the phase error based on the characteristics.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] If the signal to be measured is fixed (with the same power and modulation performance), EVM deteriorates as the noise inside the measuring device increases. Therefore, in order to perform highly reliable measurements, it is necessary to sufficiently reduce the noise inside the measuring device.

[0007] Measuring devices have a function that attenuates the input signal and suppresses noise by setting the input level to match the level of the input signal. In measuring devices, if the input level is not set higher than the level of the input signal, the input signal will be distorted, but the higher the input level, the greater the noise inside the measuring device tends to be. If the input level does not match the level of the input signal, the noise suppression effect will not be sufficient.

[0008] According to the 3GPP (3rd Generation Partnership Project) standard, symbols representing changes in the input signal level are also included in the measurement of EVM.

[0009] In such cases, it is necessary to set the input level to the level of the high-level section of the input signal. However, in this case, the signal in the low-level section of the input signal will be measured with an input level setting higher than that level, so there is room for improvement in the noise inside the measuring device for the low-level section of the input signal.

[0010] Therefore, the present invention aims to provide a measuring device that can suppress noise during EVM measurement when the level of the input signal changes by changing the input level according to the level of the input signal. [Means for solving the problem]

[0011] The measuring device of the present invention is The RB receives a signal from a wireless terminal (100) that transmits data. The system comprises at least one input port (31, 34), variable attenuators (32, 35) corresponding to the input port, and a control unit (7) that attenuates the signal input to the input port with the variable attenuator by an amount corresponding to the input level set according to the level of the signal input to the input port. An EVM measuring unit (41) measures the EVM of a predetermined section of the signal attenuated by the variable attenuator, In a measuring device equipped with such a system, when measuring an input signal consisting of multiple sections with different signal levels, the control unit changes the input level to match the section being measured when measuring each section.

[0012] This configuration allows for the measurement of an input signal consisting of multiple sections with different signal levels. The input level is adjusted for each section being measured. This suppresses noise during EVM measurements when the input signal level changes.

[0013] Furthermore, the measuring device of the present invention is The RB receives a signal from a wireless terminal (100) that transmits data. At least two input ports (31, 34), variable attenuators (32, 35) corresponding to the input ports, and a control unit (7) that attenuates the signal input to the input port with the variable attenuators by an attenuation amount corresponding to the input level set according to the level of the signal input to the input port, An EVM measuring unit (41) receives the signal attenuated by each of the aforementioned variable attenuators and measures the EVM of each predetermined section of each signal, A measuring device comprising the following, when measuring an input signal consisting of multiple sections with different signal levels, distributes the input signal to be measured to all of the input ports, and the control unit sets the input level corresponding to each section to each of the input ports. Each The measurement of the interval corresponding to the input level set at the input port is performed using the input signal of the input port.

[0014] With this configuration, when measuring an input signal consisting of multiple sections with different signal levels, the input signal to be measured is distributed to all input ports, and the input level corresponding to each section is set for each input port. Each Measurements are performed using the input signal of the input port for the section corresponding to the input level set for that input port. Therefore, noise during EVM measurement when the input signal level changes can be suppressed.

[0015] Furthermore, the measurement method of the present invention is The RB receives a signal from a wireless terminal (100) that transmits data. The system comprises at least one input port (31, 34), variable attenuators (32, 35) corresponding to the input port, and a control unit (7) that attenuates the signal input to the input port with the variable attenuator by an amount corresponding to the input level set according to the level of the signal input to the input port. An EVM measuring unit (41) measures the EVM of a predetermined section of the signal attenuated by the variable attenuator,A measurement method for a measuring device, comprising the step of changing the input level according to the section being measured when measuring an input signal consisting of multiple sections with different signal levels.

[0016] This configuration allows for the measurement of an input signal consisting of multiple sections with different signal levels. The input level is adjusted for each section being measured. This suppresses noise during EVM measurements when the input signal level changes.

[0017] Furthermore, the measurement method of the present invention is The RB receives a signal from a wireless terminal (100) that transmits data. At least two input ports (31, 34), variable attenuators (32, 35) corresponding to the input ports, and a control unit (7) that attenuates the signal input to the input port with the variable attenuators by an attenuation amount corresponding to the input level set according to the level of the signal input to the input port, An EVM measuring unit (41) receives the signal attenuated by each of the aforementioned variable attenuators and measures the EVM of each predetermined section of each signal, A measurement method for a measuring device comprising the following steps, when measuring an input signal consisting of multiple sections with different signal levels: distributing the input signal to be measured to all of the input ports; and setting the input level corresponding to each section to each of the input ports; Each The method comprises the step of measuring an interval corresponding to the input level set at the input port using the input signal of the input port.

[0018] With this configuration, when measuring an input signal consisting of multiple sections with different signal levels, the input signal to be measured is distributed to all input ports, and the input level corresponding to each section is set for each input port. Each Measurements are performed using the input signal of the input port for the section corresponding to the input level set for that input port. Therefore, noise during EVM measurement when the input signal level changes can be suppressed. [Effects of the Invention]

[0019] The present invention can provide a measuring device capable of suppressing noise during EVM measurement when the level of an input signal changes.

Brief Description of Drawings

[0020] [Figure 1] FIG. 1 is a block diagram of a measuring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the relationship between the input level of a measuring device according to an embodiment of the present invention and the noise inside the device. [Figure 3] FIG. 3 is a diagram showing an example of a signal to be measured by a measuring device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart for explaining the measurement procedure of a measuring device according to an embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart for explaining the measurement procedure of a measuring device according to another aspect of an embodiment of the present invention.

Embodiments of the Invention

[0021] Hereinafter, referring to the drawings, a measuring device according to an embodiment of the present invention will be described in detail. In FIG. 1, a measuring device 1 according to an embodiment of the present invention is connected by wire to a wireless terminal as a DUT (Device Under Test) 100 via a coaxial cable or the like, and simulates a base station to perform a measurement test on the DUT 100. The measuring device 1 may transmit and receive RF (radio frequency) signals to and from the DUT 100 wirelessly via an antenna.

[0022] The measuring device 1 includes a signal transmission unit 2, a signal reception unit 3, a signal analysis unit 4, an operation unit 5, a display unit 6, and a control unit 7.

[0023] The signal transmission unit 2 transmits a Downlink signal to the DUT 100. The signal transmission unit 2 is equipped with an output port 21. The signal transmission unit 2 is connected to the DUT 100 via the output port 21, and the Downlink signal is transmitted from the output port 21 to the DUT 100. The Downlink signal contains the information necessary for the DUT 100 to transmit the signal.

[0024] The signal receiving unit 3 receives the uplink signal from the DUT100 and converts the analog uplink signal into a digital signal.

[0025] The signal receiving unit 3 includes a first input port 31 as an input port, a first variable attenuator 32, a first AD converter 33, a second input port 34 as an input port, a second variable attenuator 35, and a second AD converter 36.

[0026] The signal receiving unit 3 is connected to the DUT 100 via the first input port 31 and the second input port 34, and the uplink signal from the DUT 100 is input to the first input port 31 and the second input port 34.

[0027] The Uplink signal input to the first input port 31 has its signal level adjusted by the first variable attenuator 32, is converted into a digital signal by the first AD converter 33, and is output to the signal analysis unit 4.

[0028] The Uplink signal input to the second input port 34 has its signal level adjusted by the second variable attenuator 35, is converted into a digital signal by the second AD converter 36, and is output to the signal analysis unit 4.

[0029] The signal analysis unit 4 performs modulation analysis of the section of the digital signal input from the signal receiving unit 3 that is being measured.

[0030] The signal analysis unit 4 includes an EVM measurement unit 41. The EVM measurement unit 41 measures the EVM of the section of the digital signal input from the signal receiving unit 3 and outputs the result to the control unit 7.

[0031] The operation unit 5 consists of input devices such as a keyboard, mouse, and touch panel, and outputs information necessary for measurement that has been input to the control unit 7. The display unit 6 consists of an image display device such as a liquid crystal display, and displays images for inputting information necessary for measurement, images showing the status during measurement, and images showing the measurement results.

[0032] The control unit 7, in accordance with the instructions input to the operation unit 5, displays the measurement settings screen on the display unit 6 and allows the user to input the information necessary for measurement. Based on the information input to the operation unit 5 on the measurement settings screen, it also notifies the signal transmission unit 2, signal reception unit 3, and signal analysis unit 4 of the information necessary for measurement. Furthermore, the control unit 7, in accordance with the instructions input to the operation unit 5, transmits instructions to the signal transmission unit 2, signal reception unit 3, and signal analysis unit 4 to execute measurements based on the notified information, and displays the measurement results on the display unit 6 based on the measurement results transmitted from the signal analysis unit 4.

[0033] Here, the measuring device 1 is composed of a computer device (not shown) equipped with a communication module for communicating with the DUT 100. This computer device includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device such as a hard disk drive, input / output ports, and a touch panel (not shown).

[0034] The ROM and hard disk drive of this computer device store programs that enable the computer device to function as measuring device 1. In other words, the CPU executes the programs stored in the ROM using the RAM as a working area, thereby enabling the computer device to function as measuring device 1.

[0035] Thus, in this embodiment, the signal analysis unit 4 and the control unit 7 are composed of a CPU, and the signal transmission unit 2 and the signal reception unit 3 are composed of a communication module.

[0036] In a measuring device 1 with this configuration, for example, as shown in Figure 2, the noise (Noise floor on the vertical axis in Figure 2) tends to increase as the input level (the horizontal axis in Figure 2) increases. In measuring device 1, the input signal will be distorted unless the input level is set higher than the level of the input signal. For this reason, measuring device 1 has a function to suppress noise by attenuating the input signal according to the input level set to match the level of the input signal.

[0037] The control unit 7 sets the attenuation amount of the variable attenuators 32 and 35 of the corresponding input ports 31 and 34 of the signal receiving unit 3 to match the input level set by the operation of the operation unit 5.

[0038] Furthermore, the 3GPP standard now includes symbols for EVM measurements when the input signal level changes, as shown at time t1 in Figure 3.

[0039] The measuring device 1 needs to set its input level to the level of the high-level section of the input signal shown in Figure 3A. However, in this case, the signal in the low-level section of the input signal shown in Figure 3B will be measured with an input level setting higher than that level, resulting in increased noise during EVM measurement within the measuring device 1.

[0040] Therefore, the measuring device 1 of this embodiment reduces noise during EVM measurement in both high and low input signal levels by switching the input level of the measuring device 1 during measurement.

[0041] When the user selects a measurement setting function through operation of the control unit 5, the control unit 7, for example, displays a measurement setting screen on the display unit 6 to set the input level, the signal to be sent to the DUT 100, and so on.

[0042] When setting up measurements where the input signal level changes, the control unit 7 sets the input level for the section where the input signal level is high and the input level for the section where the input signal level is low.

[0043] The control unit 7 sets the intervals on the time axis where the input signal level is high and intervals where the input signal level is low as schedule information.

[0044] The control unit 7, for example, sets the number of Resource Blocks (RBs) to which data is transmitted, thereby setting the intervals on the time axis and the input signal levels for high and low intervals of the input signal.

[0045] The control unit 7 may set the input level for the high-level input signal section and the input level for the low-level input signal section according to the set input signal levels for the high-level input signal section and the low-level input signal section.

[0046] The control unit 7 stores the information set in this way as setting information, associating it with the identification information.

[0047] The control unit 7 is activated when the user operates the operation unit 5 and selects to start a measurement. For example, when one of the setting information is selected from the list of setting information identification information displayed on the display unit 6, the control unit 7 starts the measurement according to the content of the selected setting information.

[0048] The control unit 7 creates signal information indicating the content of the signal to be sent to the DUT 100 from the setting information, and sends the signal information to the signal transmission unit 2.

[0049] When the signal transmission unit 2 receives signal information, it sends a signal to the DUT 100 instructing it to send a signal corresponding to the content of the signal information. As a result, the DUT 100 transmits a signal that repeats the same pattern, as shown in Figure 3.

[0050] The signal transmission unit 2, for example, notifies the DUT 100 of the number of RBs to be allocated in each section on the time axis and specifies the signal to be transmitted to the DUT 100.

[0051] The control unit 7 transmits schedule information indicating the position of the signal to be measured on the time axis, based on the setting information, to the signal analysis unit 4.

[0052] When the signal analysis unit 4 receives schedule information, it measures the EVM at the position on the time axis of the signal to be measured, according to the schedule information.

[0053] The control unit 7 sets the attenuation amount corresponding to the set input level in the variable attenuators 32 and 35 of the signal receiving unit 3 according to the schedule information.

[0054] When the level of the input signal changes during measurement, the control unit 7 switches the input level according to the level of the input signal.

[0055] For example, when receiving a signal to be measured that is repeatedly received, as shown in Figure 3, the control unit 7 sets the input level attenuation amount corresponding to the first section, which is a section where the input signal level is high, to the variable attenuators 32 and 35 during the first reception, and sets the input level attenuation amount corresponding to the second section, which is a section where the input signal level is low, to the variable attenuators 32 and 35 during the second reception.

[0056] The EVM measurement process using the measuring device 1 configured as described above according to this embodiment will be explained with reference to Figure 4. The EVM measurement process described below is started when the user selects to start EVM measurement by operating the operation unit 5.

[0057] In step S1, the control unit 7 notifies the DUT 100 of the RF signal transmission level via the signal transmission unit 2. After executing the process in step S1, the control unit 7 executes the process in step S2.

[0058] In step S2, the control unit 7 sets the attenuation amount of the first input level corresponding to the first section of the measurement target to the variable attenuators 32 and 35. After executing the process in step S2, the control unit 7 executes the process in step S3.

[0059] In step S3, the control unit 7 measures the EVM of the first section using the EVM measurement unit 41. After performing the process in step S3, the control unit 7 performs the process in step S4.

[0060] In step S4, the control unit 7 sets the attenuation amount of the second input level corresponding to the second section of the measurement target to the variable attenuators 32 and 35. After executing the process in step S4, the control unit 7 executes the process in step S5.

[0061] In step S5, the control unit 7 measures the EVM of the second section using the EVM measurement unit 41. After executing the process in step S5, the control unit 7 executes the process in step S6.

[0062] In step S6, the control unit 7 displays the measurement results on the display unit 6. After executing the process in step S6, the control unit 7 terminates the EVM measurement process.

[0063] Thus, in the above-described embodiment, when the control unit 7 measures an input signal whose signal level is changing, it changes the input level in accordance with the change in the input signal level and then measures it.

[0064] This allows the input level to be changed in accordance with changes in the input signal level. Therefore, noise during EVM measurement when the input signal level changes can be suppressed.

[0065] In another aspect of this embodiment, as shown in Figure 1, the Uplink signal from the DUT 100 is distributed to the first input port 31 and the second input port 34 by a distributor or the like.

[0066] The control unit 7 measures the first section based on the Uplink signal input to the first input port 31, and measures the second section based on the Uplink signal input to the second input port 34.

[0067] At this time, the control unit 7 sets the first variable attenuation amount of the first input level corresponding to the first section in the first variable attenuation unit 32, and sets the second variable attenuation amount of the second input level corresponding to the second section in the second variable attenuation unit 35.

[0068] An EVM measurement process using the measuring device 1 according to another embodiment of this model, configured as described above, will be explained with reference to Figure 5. The EVM measurement process described below is started when the user selects to start EVM measurement by operating the operation unit 5.

[0069] In step S11, the control unit 7 notifies the DUT 100 of the RF signal transmission level via the signal transmission unit 2. After executing the process in step S11, the control unit 7 executes the process in step S12.

[0070] In step S12, the control unit 7 sets a first input level attenuation amount corresponding to the first interval in the first variable attenuator 32 connected to the first input port 31, and sets a second input level attenuation amount corresponding to the second interval in the second variable attenuator 35 connected to the second input port 34. After executing the process in step S12, the control unit 7 executes the process in step S13.

[0071] In step S13, the control unit 7 measures the EVM of a first section using the EVM measurement unit 41 based on the signal from the first AD converter 33 connected to the first input port 31, and measures the EVM of a second section using the EVM measurement unit 41 based on the signal from the second AD converter 36 connected to the second input port 34. After executing the process in step S13, the control unit 7 executes the process in step S14.

[0072] In step S14, the control unit 7 displays the measurement results on the display unit 6. After executing the process in step S14, the control unit 7 terminates the EVM measurement process.

[0073] As described above, in the embodiment, the control unit 7 sets a first input level corresponding to the first interval to the first input port 31, sets a second input level corresponding to the second interval to the second input port 34, measures the first interval using the input signal from the first input port 31, and measures the second interval using the input signal from the second input port 34.

[0074] As a result, a first input level is set for the input signal of the first input port 31, and measurement of the first section is performed, and a second input level is set for the input signal of the second input port 34, and measurement of the second section is performed. Therefore, noise during EVM measurement when the level of the input signal changes can be suppressed.

[0075] Furthermore, the measurement of the input signal from the first input port 31 and the input signal from the second input port 34 can be performed at the same time, thereby shortening the measurement time.

[0076] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of symbols]

[0077] 1. Measuring device 2. Signal transmission unit 3. Signal receiving unit 4 Signal analysis section 7 Control Unit 31. First Input Port (Input Port) 32. First Variable Attenuator (Variable Attenuator) 33. First AD Converter 34. Second input port (input port) 35. Second Variable Attenuator (Variable Attenuator) 36. Second AD Converter 41 EVM measurement section 100 DUT

Claims

1. A measuring device comprising: at least one input port (31, 34) that receives a signal from a wireless terminal (100) that transmits data by RB; variable attenuators (32, 35) corresponding to the input port; a control unit (7) that attenuates the signal input to the input port with the variable attenuator by an attenuation amount corresponding to an input level set to match the level of the signal input to the input port; and an EVM measuring unit (41) that measures the EVM of a predetermined section of the signal attenuated by the variable attenuator, wherein When measuring an input signal consisting of multiple sections with different signal levels, the control unit changes the input level according to the section being measured during measurement of each section.

2. A measuring device comprising: at least two input ports (31, 34) that receive signals from a wireless terminal (100) that transmits data by RB; variable attenuators (32, 35) corresponding to the input ports; a control unit (7) that attenuates the signals input to the input ports with the variable attenuators by an attenuation amount corresponding to an input level set to match the level of the signals input to the input ports; and an EVM measuring unit (41) that receives the signals attenuated by each of the variable attenuators and measures the EVM of each predetermined section of each signal, wherein When measuring an input signal consisting of multiple sections with different signal levels, the input signal to be measured is distributed to all of the aforementioned input ports. The control unit sets an input level corresponding to each section for each of the input ports, and the measuring device measures the section corresponding to the input level set for each of the input ports using the input signal of the input port.

3. A measurement method for a measuring device comprising: at least one input port (31, 34) that receives a signal from a wireless terminal (100) that transmits data by RB; variable attenuators (32, 35) corresponding to the input port; a control unit (7) that attenuates the signal input to the input port with the variable attenuator by an attenuation amount corresponding to an input level set to match the level of the signal input to the input port; and an EVM measuring unit (41) that measures the EVM of a predetermined section of the signal attenuated by the variable attenuator, the method being used When measuring an input signal consisting of multiple sections with different signal levels, A measurement method that includes a step of changing the input level according to the section being measured when measuring each section.

4. A measurement method for a measuring device comprising: at least two input ports (31, 34) that receive signals from a wireless terminal (100) that transmits data by RB; variable attenuators (32, 35) corresponding to the input ports; a control unit (7) that attenuates the signals input to the input ports with the variable attenuators by an attenuation amount corresponding to an input level set to match the level of the signals input to the input ports; and an EVM measuring unit (41) that receives the signals attenuated by each of the variable attenuators and measures the EVM of each predetermined section of each signal, wherein When measuring an input signal consisting of multiple sections with different signal levels, The steps include distributing the input signal to be measured to all of the input ports, The steps include setting the input level corresponding to each section for each of the input ports, A measurement method comprising the step of measuring an interval corresponding to the input level set for each of the aforementioned input ports using the input signal of the input port.

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