Measuring apparatus and measuring method of the same

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 for measuring radio waves transmitted by a wireless terminal in a mobile communication system. [Background technology]

[0002] For wireless terminals that transmit and receive wireless signals compatible with IEEE802.11ad and 5G cellular, which use wideband signals in the millimeter wave band and have been developed in recent years, performance tests are conducted on the wireless communication antennas equipped on the wireless terminals to measure the output level and receiving sensitivity of the transmitted radio waves specified for each communication standard and determine whether they meet the specified standards.

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

[0004] Patent Document 1 describes a technique in which the characteristics of a phase error are estimated using only signal data corresponding to symbols having an EVM smaller than a predetermined reference value, and the phase error is corrected based on the characteristics. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-17519 Summary of the Invention [Problem to be solved by the invention]

[0006] If the signal to be measured is fixed (with the same power and modulation performance), the EVM worsens as the noise inside the measurement equipment increases. Therefore, to perform reliable measurements, it is necessary to sufficiently reduce the noise inside the measurement equipment.

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

[0008] The 3GPP (3rd Generation Partnership Project) standard now includes symbols when the input signal level changes as targets for EVM measurement.

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

[0010] Therefore, an object of the present invention is to provide a measurement device that can suppress noise during EVM measurement when the input signal level changes by changing the input level in accordance with the level of the input signal. [Means for solving the problem]

[0011] The measuring device of the present invention comprises at least one input port (31, 34), a variable attenuator (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 of attenuation corresponding to an input level that is set according to the level of the signal input to the input port, and 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 when measuring each section.

[0012] With this configuration, when measuring an input signal consisting of multiple sections with different signal levels, the input level is changed to match the section being measured during each measurement, which makes it possible to suppress noise during EVM measurement when the input signal level changes.

[0013] Furthermore, the measuring device of the present invention is a measuring device comprising 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 ports with the variable attenuators by an amount of attenuation corresponding to an input level set in accordance with the level of the signal input to the input ports. 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 input ports, and the control unit sets input levels corresponding to each section to each of the input ports, and measures the section corresponding to the input level set to the input port using the input signal at that 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, input levels corresponding to each section are set for each input port, and the section corresponding to the input level set for the input port is measured using the input signal at that input port.This makes it possible to suppress noise during EVM measurement when the input signal level changes.

[0015] Furthermore, the measurement method of the present invention is a measurement method for a measurement device comprising at least one input port (31, 34), a variable attenuator (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 of attenuation according to an input level that is set according to the level of the signal input to the input port, and when measuring an input signal consisting of multiple sections with different signal levels, the measurement method comprises a step of changing the input level according to the section to be measured when measuring each section.

[0016] With this configuration, when measuring an input signal consisting of multiple sections with different signal levels, the input level is changed to match the section being measured during each measurement, which makes it possible to suppress noise during EVM measurement when the input signal level changes.

[0017] Furthermore, the measurement method of the present invention is a measurement method for a measurement device comprising 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 ports with the variable attenuator by an amount of attenuation according to an input level set in accordance with the level of the signal input to the input ports, and when measuring an input signal consisting of multiple sections with different signal levels, the measurement method comprises the steps of distributing the input signal to be measured to all of the input ports, setting input levels corresponding to each section to each of the input ports, and measuring the section corresponding to the input level set to the input port with the input signal to 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, input levels corresponding to each section are set for each input port, and the section corresponding to the input level set for the input port is measured using the input signal at that input port.This makes it possible to suppress noise during EVM measurement when the input signal level changes. [Effects of the Invention]

[0019] The present invention can provide a measurement device that can suppress noise during EVM measurement when the input signal level changes. [Brief explanation of the drawings]

[0020] [Figure 1]FIG. 1 is a block diagram of a measurement device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the relationship between the input level of a measurement device according to one embodiment of the present invention and noise within the device. [Figure 3] FIG. 3 is a diagram showing an example of a signal to be measured by the measurement device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart illustrating the procedure of the measurement process of the measurement device according to one embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart illustrating the procedure of a measurement process of a measurement device according to another aspect of one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a measuring device according to an embodiment of the present invention will be described in detail with reference to the drawings. 1, a measurement apparatus 1 according to an embodiment of the present invention is connected to a wireless terminal serving as a DUT (Device Under Test) 100 via a wired connection such as a coaxial cable, and performs a measurement test on the DUT 100 by simulating a base station. Note that the measurement apparatus 1 may also be configured to wirelessly transmit and receive RF (radio frequency) signals to and from the DUT 100 via an antenna.

[0022] The measurement device 1 includes a signal transmitting section 2, a signal receiving section 3, a signal analyzing section 4, an operating section 5, a display section 6, and a control section .

[0023] The signal transmitting unit 2 transmits a downlink signal to the DUT 100. The signal transmitting unit 2 has an output port 21. The signal transmitting unit 2 is connected to the DUT 100 via the output port 21, and transmits the downlink signal from the output port 21 to the DUT 100. The downlink signal includes information necessary for the DUT 100 to transmit the signal.

[0024] The signal receiving unit 3 receives an uplink signal from the DUT 100 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 an 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 digital signal input from the signal receiving unit 3 in the section to be measured.

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

[0031] The operation unit 5 is composed of input devices such as a keyboard, mouse, touch panel, etc., and outputs information necessary for measurement that has been input through operation to the control unit 7. The display unit 6 is composed 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, images showing the measurement results, etc.

[0032] The control unit 7 displays a measurement setting screen on the display unit 6 and allows the user to input information necessary for measurement according to instructions input to the operation unit 5, and notifies the signal transmitting unit 2, the signal receiving unit 3, and the signal analyzing unit 4 of information for measurement based on the information input to the operation unit 5 on the measurement setting screen. Furthermore, the control unit 7 sends instructions to the signal transmitting unit 2, the signal receiving unit 3, and the signal analyzing unit 4 according to instructions input to the operation unit 5, causing them to perform measurement based on the notified information, and causing the display unit 6 to display measurement results, etc. based on the measurement results transmitted from the signal analyzing unit 4.

[0033] Here, the measurement device 1 is configured by a computer device (not shown) provided with a communication module for communicating with the DUT 100. This computer device has a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device such as a hard disk drive, an input / output port, and a touch panel (all not shown).

[0034] The ROM and hard disk drive of this computer device store a program for causing the computer device to function as the measurement device 1. That is, the CPU executes the program stored in the ROM using the RAM as a working area, causing the computer device to function as the measurement device 1.

[0035] As described above, in this embodiment, the signal analysis unit 4 and the control unit 7 are configured by a CPU, and the signal transmission unit 2 and the signal reception unit 3 are configured by a communication module.

[0036] In a measuring device 1 configured as described above, as shown in FIG. 2, the noise (the "Noise floor" on the vertical axis in FIG. 2) tends to increase as the input level (the "Input Level" on the horizontal axis in FIG. 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 attenuate the input signal and suppress noise according to the input level set in accordance with the level of the input signal.

[0037] The control unit 7 sets the attenuation amounts of the variable attenuators 32 and 35 of the corresponding input ports 31 and 34 of the signal receiving unit 3 in accordance with the input level set by operating the operation unit 5 .

[0038] Furthermore, the 3GPP standard also includes symbols where the input signal level changes, such as at time t1 in FIG. 3, as targets for EVM measurement.

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

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

[0041] When the user operates the operation unit 5 to select a measurement setting function, the control unit 7 causes, for example, the display unit 6 to display a measurement setting screen, and causes the user to set the input level, the signal to be transmitted to the DUT 100, and so on.

[0042] In the measurement settings when the level of the input signal changes, the control unit 7 sets the input level for a section where the level of the input signal is high and the input level for a section where the level is low.

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

[0044] The control unit 7 sets the intervals on the time axis where the level of the input signal is high or low, and the level of the input signal, for example, by setting the number of RBs (Resource Blocks) for transmitting data.

[0045] The control unit 7 may set 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 in accordance with the set input signal level for the section where the input signal level is high and the input signal level for the section where the input signal level is low.

[0046] The control unit 7 stores the information thus set as setting information in association with the identification information.

[0047] When the user operates the operation unit 5 to select the start of measurement, for example, when one of the setting information is selected from the list of identification information of the setting information displayed on the display unit 6, the control unit 7 starts measurement in accordance with the contents of the selected setting information.

[0048] The control unit 7 creates signal information indicating the content of the signal to be transmitted by the DUT 100 from the setting information, and transmits the signal information to the signal transmitting unit 2.

[0049] When the signal transmitting unit 2 receives the signal information, it transmits a signal to the DUT 100 to cause the DUT 100 to transmit a signal having the content indicated by the signal information. As a result, the DUT 100 transmits a signal having the same pattern repeatedly, as shown in FIG.

[0050] The signal transmitting unit 2 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 by the DUT 100, for example.

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

[0052] Upon receiving the schedule information, the signal analysis unit 4 measures the EVM at the position on the time axis of the signal to be measured in accordance with the schedule information.

[0053] The control unit 7 sets the attenuation amounts corresponding to the set input levels in the variable attenuators 32 and 35 of the signal receiving unit 3 in accordance with the schedule information.

[0054] In the case of a measurement in which the level of the input signal changes, the control unit 7 switches the input level in accordance with the level of the input signal.

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

[0056] The EVM measurement process performed by the measurement apparatus 1 according to this embodiment configured as described above will be described with reference to Fig. 4. The EVM measurement process described below starts when the user operates the operation unit 5 to select the start of EVM measurement.

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

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

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

[0060] In step S4, the control unit 7 sets the attenuation amount of the second input level corresponding to the second section to be measured in the variable attenuators 32 and 35. After executing the process of step S4, the control unit 7 executes the process of 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 of step S5, the control unit 7 executes the process of step S6.

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

[0063] As described above, in the above embodiment, when measuring an input signal whose level changes, the control unit 7 changes the input level in accordance with the change in the level of the input signal and performs the measurement.

[0064] This allows the input level to be changed in accordance with changes in the input signal level, making it possible to suppress noise during EVM measurement when the input signal level changes.

[0065] In another aspect of this embodiment, in FIG. 1, an uplink signal from the DUT 100 is split into the first input port 31 and the second input port 34 by a splitter or the like.

[0066] The control unit 7 measures the first section using the uplink signal input to the first input port 31, and measures the second section using the uplink signal input to the second input port .

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

[0068] The EVM measurement process performed by the measurement apparatus 1 according to another aspect of this embodiment configured as described above will be described with reference to Fig. 5. The EVM measurement process described below starts when the user operates the operation unit 5 to select the start of EVM measurement.

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

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

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

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

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

[0074] As a result, a first input level is set for the input signal to the first input port 31 and measurement is performed in the first section, and a second input level is set for the input signal to the second input port 34 and measurement is performed in the second section, thereby making it possible to suppress noise during EVM measurement when the input signal level changes.

[0075] Furthermore, the input signal at the first input port 31 and the input signal at the second input port 34 can be measured at the same time, thereby reducing the measurement time.

[0076] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0077] 1. Measuring equipment 2. Signal transmitter 3. Signal receiving section 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); a variable attenuator (32, 35) corresponding to the input port; and a control unit (7) that attenuates a signal input to the input port by the variable attenuator by an amount of attenuation according to an input level that is set in accordance with the level of the signal input to the input port, 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.

2. A measuring device comprising: at least two input ports (31, 34); variable attenuators (32, 35) corresponding to the input ports; and a control unit (7) that attenuates a signal input to the input ports by the variable attenuators by an amount of attenuation according to an input level that is set in accordance with the level of the signal input to the input ports, 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 input ports, The control unit sets an input level corresponding to each section to each of the input ports, and measures the section corresponding to the input level set to the input port using the input signal of the input port.

3. A measurement method for a measurement device comprising at least one input port (31, 34), a variable attenuator (32, 35) corresponding to the input port, and a control unit (7) that attenuates a signal input to the input port by the variable attenuator by an amount of attenuation according to an input level that is set in accordance with the level of the signal input to the input port, When measuring an input signal consisting of multiple sections with different signal levels, A measurement method comprising a step of changing an input level in accordance with the section being measured when measuring each section.

4. A measurement method for a measurement device comprising at least two input ports (31, 34), variable attenuators (32, 35) corresponding to the input ports, and a control unit (7) that attenuates a signal input to the input ports with the variable attenuators by an amount of attenuation according to an input level that is set in accordance with the level of the signal input to the input ports, comprising: When measuring an input signal consisting of multiple sections with different signal levels, Distributing an input signal to be measured to all of the input ports; setting an input level corresponding to each section to each of the input ports; and measuring an input signal to the input port in a section corresponding to an input level set to the input port.

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