Measuring device and measuring method thereof

Abstract

Provided is a measurement device capable of suppressing noise when performing EVM measurement when the level of an input signal changes. A measurement device is provided with: a first input port (31); a first variable attenuator (32) that attenuates the signal level of the uplink signal input to the first input port (31) in accordance with the set input level; a first AD converter (33) that converts the analog signal attenuated by the first variable attenuator (32) into a digital signal; a signal analysis unit (4) that performs modulation analysis on a section to be measured of the digital signal output from the first AD converter (33); and a control unit (7) that, when measuring an input signal comprising a plurality of sections and having different signal levels for each section, changes the input level in accordance with the measured section when measuring each section.

Description

Technical Field

[0001] This invention relates to a measuring device for measuring radio waves transmitted by a wireless terminal of a mobile communication system. Background Technology

[0002] For wireless terminals that are being developed in recent years to transmit and receive broadband signals in the millimeter wave band, such as IEEE 802.11ad and 5G cellular, the performance tests are conducted on the wireless communication antennas of the wireless terminals to measure the output level of the transmitted radio waves and the receiving sensitivity set according to each communication standard, and to determine whether they meet the specified benchmarks.

[0003] As one such measurement item, there is EVM (Error Vector Magnitude). EVM represents the deviation between the measured signal and the theoretically modulated signal when digital modulation is applied.

[0004] Patent Document 1 describes the following: a characteristic of estimating phase error using only signal data corresponding to symbols of EVM with a value less than a specified reference value, and correcting phase error based on this characteristic.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-17519

[0006] If the signal of the object being measured is fixed (with the same power and modulation performance), the greater the noise inside the measuring device, the worse the EVM (Electronic Performance Measurement). Therefore, to perform reliable measurements, it is necessary to significantly reduce the noise inside the measuring device.

[0007] The measuring device has the function of attenuating the input signal to suppress noise by setting the input level according to the level of the input signal. In the measuring device, if the input level is not set higher than the input signal level, the input signal will be distorted; however, there is a tendency for the higher the input level, the greater the noise inside the measuring device. If the input level does not match the input signal level, the noise suppression effect cannot be fully achieved.

[0008] In the 3GPP (3rd Generation Partnership Project) standard, the symbol of the input signal when the level changes also becomes the object of EVM measurement.

[0009] In this case, the input level needs to be set to the level of the high range of the input signal. However, this will cause the signal in the low range of the input signal to be measured at an input level higher than that setting. Therefore, there is room for improvement in the noise inside the measuring device for the low range of the input signal. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide a noise measurement device for EVM measurement that can suppress changes in the level of the input signal by changing the input level according to the level of the input signal.

[0011] The measuring device of the present invention includes 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 by means of the variable attenuator with an attenuation amount corresponding to a set input level. When measuring an input signal consisting of multiple intervals with different signal levels in each interval, the control unit changes the input level according to the interval being measured when measuring each interval.

[0012] According to this structure, when measuring an input signal consisting of multiple intervals with different signal levels, the input level is changed according to the interval being measured. Therefore, noise during EVM measurement can be suppressed even when the input signal level changes.

[0013] Furthermore, the measuring device of the present invention includes at least two input ports 31 and 34, variable attenuators 32 and 35 corresponding to the input ports, and a control unit 7 that attenuates the signal input to the input ports by means of the variable attenuators with an attenuation amount corresponding to the set input level. In the case of measuring an input signal consisting of multiple intervals with different signal levels in each interval, the input signal to be measured is distributed to all the input ports. The control unit sets the input level corresponding to each interval to the input port respectively, and the measurement of each interval is performed using the input signal of the input port set with the input level corresponding to each interval.

[0014] According to this structure, when measuring an input signal consisting of multiple intervals with different signal levels, the input signal to be measured is distributed to all input ports. The input level corresponding to each interval is set on each input port, and the measurement of each interval is performed using the input signal of the input port set with the input level corresponding to each interval. Therefore, noise during EVM measurement can be suppressed even when the input signal level changes.

[0015] Furthermore, the measurement method of the present invention is a measurement method of a measuring device, the measuring device having 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 by means of the variable attenuator with an attenuation amount corresponding to a set input level. The measurement method includes the following steps: when measuring an input signal consisting of multiple intervals and each interval having a different signal level, when measuring each interval, the input level is changed according to the interval being measured.

[0016] According to this structure, when measuring an input signal consisting of multiple intervals with different signal levels, the input level is changed according to the interval being measured. Therefore, noise during EVM measurement can be suppressed even when the input signal level changes.

[0017] Furthermore, the measurement method of the present invention is a measurement method for a measuring device, the measuring device having 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 by means of the variable attenuators with an attenuation amount corresponding to a set input level. The measurement method includes the following steps: when measuring an input signal consisting of multiple intervals with different signal levels in each interval, the input signal to be measured is distributed to all the input ports; the input level corresponding to each interval is set at the input port respectively; and the measurement of each interval is performed using the input signal of the input port set with the input level corresponding to each interval.

[0018] According to this structure, when measuring an input signal consisting of multiple intervals with different signal levels, the input signal to be measured is distributed to all input ports. The input level corresponding to each interval is set on each input port, and the measurement of each interval is performed using the input signal of the input port set with the input level corresponding to each interval. Therefore, noise during EVM measurement can be suppressed even when the input signal level changes.

[0019] The present invention provides a noise measurement device for EVM measurement that can suppress changes in the level of the input signal. Attached Figure Description

[0020] Figure 1 This is a block diagram of a measuring device according to one embodiment of the present invention.

[0021] Figure 2 This is a diagram illustrating an example of the relationship between the input level of a measuring device according to an embodiment of the present invention and the noise within the device.

[0022] Figure 3 This is a diagram illustrating an example of a signal of the object being measured by a measuring device according to an embodiment of the present invention.

[0023] Figure 4 This is a flowchart illustrating the measurement processing steps of a measuring device according to an embodiment of the present invention.

[0024] Figure 5 This is a flowchart illustrating the measurement processing steps of a measuring device according to another embodiment of the present invention. Detailed Implementation

[0025] Hereinafter, the measuring device according to the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] exist Figure 1 In one embodiment of the present invention, the measuring device 1 is connected in a wired manner to a wireless terminal, which is a DUT (Device Under Test), via a coaxial cable or the like, and performs measurement tests on the DUT 100 by simulating a base station. Alternatively, the measuring device 1 can also wirelessly transmit and receive RF (radio frequency) signals with the DUT 100 via an antenna.

[0027] The measuring device 1 comprises a signal transmitting unit 2, a signal receiving unit 3, a signal analysis unit 4, an operation unit 5, a display unit 6, and a control unit 7.

[0028] Signal transmitting unit 2 transmits downlink signals to DUT 100. Signal transmitting unit 2 has an output port 21. Signal transmitting unit 2 is connected to DUT 100 via output port 21 and transmits downlink signals to DUT 100 from output port 21. The downlink signals contain information required for DUT 100 to transmit signals.

[0029] The signal receiving unit 3 receives the uplink signal from the DUT100 and converts the analog uplink signal into a digital signal.

[0030] 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.

[0031] The signal receiving unit 3 is connected to the DUT100 via the first input port 31 and the second input port 34, and the uplink signal from the DUT100 is input to the first input port 31 and the second input port 34.

[0032] The uplink signal input to the first input port 31 has its signal level adjusted by the first variable attenuator 32, converted into a digital signal by the first AD converter 33, and output to the signal analysis unit 4.

[0033] The uplink signal input to the second input port 34 has its signal level adjusted by the second variable attenuator 35, converted into a digital signal by the second AD converter 36, and output to the signal analysis unit 4.

[0034] The signal analysis unit 4 performs modulation analysis on the interval of the digital signal input from the signal receiving unit 3 that is the object of measurement.

[0035] The signal analysis unit 4 includes an EVM measurement unit 41. The EVM measurement unit 41 measures the EVM of the range of the digital signal input from the signal receiving unit 3 that is the object of measurement, and outputs the result to the control unit 7.

[0036] The operation unit 5 consists of input devices such as a keyboard, mouse, and touch panel, and outputs the measurement-required information to the control unit 7. The display unit 6 consists of an image display device such as a liquid crystal display, and displays images of the measurement-required information, images indicating the measurement status, and images indicating the measurement results.

[0037] The control unit 7 displays the measurement setting screen on the display unit 6 and inputs the information required for the measurement, according to the instructions input to the operation unit 5 on the measurement setting screen. Alternatively, it notifies the signal transmitting unit 2, signal receiving unit 3, and signal analysis unit 4 of the measurement information based on the information input to the operation unit 5. Furthermore, the control unit 7 sends instructions to the signal transmitting unit 2, signal receiving unit 3, and signal analysis unit 4 according to the instructions input to the operation unit 5, and performs the measurement based on the notified information. It also displays the measurement results on the display unit 6 based on the measurement results sent from the signal analysis unit 4.

[0038] Here, the measuring device 1 consists of a computer device (not shown) equipped with a communication module for communicating with the DUT100. This computer device has storage devices (not shown), such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and hard disk drive, as well as input / output ports and a touch panel.

[0039] The computer device stores programs in its ROM and hard disk for functioning as measuring device 1. Specifically, the CPU uses the RAM as its working area to execute the programs stored in the ROM, thus enabling the computer device to function as measuring device 1.

[0040] Thus, in this embodiment, the signal analysis unit 4 and the control unit 7 are composed of CPUs, and the signal transmission unit 2 and the signal receiving unit 3 are composed of communication modules.

[0041] In the measuring device 1 of this structure, for example, as Figure 2 As shown, it has an input level (in Figure 2 The higher the "Input Level" (horizontal axis), the greater the noise (in...). Figure 2 The "Noise floor" (vertical axis) tends to increase. In measuring device 1, if the input level is not set higher than the input signal level, the input signal will be distorted. Therefore, measuring device 1 has the function of attenuating the input signal according to the input signal level to suppress noise.

[0042] The control unit 7 sets the attenuation of the variable attenuators 32 and 35 of the corresponding input ports 31 and 34 of the signal receiving unit 3 based on the input level set by the operation of the operation unit 5.

[0043] Furthermore, in the 3GPP standard, such as Figure 3 At time t1, the symbol of the input signal when the level changes also becomes the object of EVM measurement.

[0044] Measuring device 1 needs to set the input level to Figure 3 The input signal level represented by A is in the high-level range, but in this case, it will lead to... Figure 3 The signal in the low range of the input signal represented by B is measured at a higher input level setting, which will cause the noise during EVM measurement in the measuring device 1 to increase.

[0045] Therefore, the measuring device 1 of this embodiment reduces the noise during EVM measurement in both the high and low ranges of the input signal by switching the input level of the measuring device 1 during measurement.

[0046] If the user selects the measurement setting function through the operation unit 5, the control unit 7 will display the measurement setting screen on the display unit 6, and set the input level, the signal sent to the DUT100, etc.

[0047] In setting the measurement when the level of the input signal changes, the control unit 7 sets the input level for the high range and the input level for the low range of the input signal.

[0048] The control unit 7 sets the intervals with high input signal levels and low input signal levels on the time axis as scheduling information.

[0049] Control unit 7, for example, sets the number of RBs (Resource Blocks) for transmitting data, and sets the level of the input signal on the time axis for the high and low ranges of the input signal level.

[0050] The control unit 7 can also set the input level of the high range and the input level of the low range of the input signal based on the input signal level of the high range and the input signal level of the low range of the input signal.

[0051] The control unit 7 associates and stores the information set in this way with the identification information as setting information.

[0052] The user selects the start of the measurement by operating the operation unit 5. For example, if a setting information is selected from the list of identification information displayed on the display unit 6, the control unit 7 will start the measurement according to the content of the selected setting information.

[0053] The control unit 7 generates signal information representing the content of the signal to be sent to the DUT100 based on the setting information, and sends the signal information to the signal transmitting unit 2.

[0054] If a signal is received, the signal transmitting unit 2 will send a signal to the DUT100 containing the content shown in the signal information. Thus, the DUT100 sends a signal as shown in the signal information. Figure 3 The signal shown is a repeating pattern.

[0055] For example, the signal transmitting unit 2 notifies the DUT100 of the number of RBs allocated in each interval on the time axis and specifies the signal to be transmitted to the DUT100.

[0056] The control unit 7 sends scheduling information, which indicates the position of the signal that is being measured on the time axis, to the signal analysis unit 4 based on the setting information.

[0057] If scheduling information is received, the signal analysis unit 4 performs EVM measurement at the position on the time axis of the signal that is being measured, according to the scheduling information.

[0058] According to the scheduling information, the control unit 7 sets the attenuation amount corresponding to the set input level to the variable attenuators 32 and 35 of the signal receiving unit 3.

[0059] When measuring changes in the level of the input signal, the control unit 7 switches the input level according to the level of the input signal.

[0060] Control unit 7, for example, upon first receiving... Figure 3When repeatedly receiving the signal that is being measured, the attenuation of the input level corresponding to the high level range of the input signal, i.e., the first range, is set in the variable attenuators 32 and 35. During the second reception, the attenuation of the input level corresponding to the low level range of the input signal, i.e., the second range, is set in the variable attenuators 32 and 35.

[0061] refer to Figure 4 The EVM measurement process performed by the measuring device 1 according to this embodiment, configured as described above, will be explained. Furthermore, if the user selects to start the EVM measurement via operation of the operation unit 5, the EVM measurement process described below will begin.

[0062] In step S1, the control unit 7 notifies the DUT100 of the RF signal transmission level via the signal transmission unit 2. After performing the processing in step S1, the control unit 7 performs the processing in step S2.

[0063] In step S2, the control unit 7 sets the attenuation amount of the first input level corresponding to the first interval of the measurement object to the variable attenuators 32 and 35. After performing the processing in step S2, the control unit 7 performs the processing in step S3.

[0064] In step S3, the control unit 7 measures the EVM of the first interval using the EVM measurement unit 41. After performing the processing in step S3, the control unit 7 performs the processing in step S4.

[0065] In step S4, the control unit 7 sets the attenuation amount of the second input level corresponding to the second interval of the measurement object to the variable attenuators 32 and 35. After performing the processing in step S4, the control unit 7 performs the processing in step S5.

[0066] In step S5, the control unit 7 measures the EVM of the second interval using the EVM measurement unit 41. After performing the processing in step S5, the control unit 7 performs the processing in step S6.

[0067] In step S6, the control unit 7 displays the measurement results on the display unit 6. After executing the processing in step S6, the control unit 7 ends the EVM measurement process.

[0068] Thus, in the above embodiment, when the level of the input signal changes, the control unit 7 changes the input level and performs measurement according to the change in the level of the input signal.

[0069] Therefore, the input level changes according to the level of the input signal. This allows for the suppression of noise during EVM measurements even when the input signal level changes.

[0070] As another aspect of this implementation, Figure 1In the process, the uplink signal from DUT100 is distributed to the first input port 31 and the second input port 34 through a distributor, etc.

[0071] The control unit 7 performs a measurement of the first interval based on the uplink signal input to the first input port 31, and performs a measurement of the second interval based on the uplink signal input to the second input port 34.

[0072] At this time, the control unit 7 sets the attenuation amount of the first input level corresponding to the first interval to the first variable attenuator 32, and sets the attenuation amount of the second input level corresponding to the second interval to the second variable attenuator 35.

[0073] refer to Figure 5 The EVM measurement process performed by the measuring device 1 according to another embodiment of this invention, configured as described above, will be explained. Furthermore, if the user selects to start the EVM measurement via operation of the operation unit 5, the EVM measurement process described below will begin.

[0074] In step S11, the control unit 7 notifies the DUT100 of the RF signal transmission level via the signal transmission unit 2. After executing step S11, the control unit 7 executes step S12.

[0075] In step S12, the control unit 7 sets the attenuation amount of the first input level corresponding to the first interval for the first variable attenuator 32 connected to the first input port 31, and sets the attenuation amount of the second input level corresponding to the second interval for the second variable attenuator 35 connected to the second input port 34. After executing the processing in step S12, the control unit 7 executes the processing in step S13.

[0076] In step S13, the control unit 7 measures the EVM of the first interval via 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 the second interval via the EVM measurement unit 41 based on the signal from the second AD converter 36 connected to the second input port 34. After performing the processing in step S13, the control unit 7 performs the processing in step S14.

[0077] In step S14, the control unit 7 displays the measurement results on the display unit 6. After executing the processing in step S14, the control unit 7 ends the EVM measurement process.

[0078] Thus, in the above 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, performs measurement of the first interval using the input signal of the first input port 31, and performs measurement of the second interval using the input signal of the second input port 34.

[0079] Therefore, a first input level is set for the input signal at the first input port 31 to perform a measurement in the first interval, and a second input level is set for the input signal at the second input port 34 to perform a measurement in the second interval. Thus, noise during EVM measurement can be suppressed even when the input signal level changes.

[0080] Furthermore, the measurement of the input signal at the first input port 31 and the input signal at the second input port 34 can be performed at the same time, thus shortening the measurement time.

[0081] Embodiments of the present invention have been disclosed, but it will be apparent to those skilled in the art that additional modifications can be made without departing from the scope of the invention. Of course, all such modifications and equivalents are included within the scope of this technical solution.

[0082] Symbol Explanation

[0083] 1-Measuring device, 2-Signal transmitting unit, 3-Signal receiving unit, 4-Signal analysis unit, 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 measuring unit, 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) for attenuating a signal input to the input port by means of the variable attenuator by an attenuation amount corresponding to a set input level, wherein, When measuring an input signal consisting of multiple intervals with different signal levels in each interval, the control unit changes the input level according to the interval being measured.

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 the signal input to the input ports by means of the variable attenuators with an attenuation amount corresponding to a set input level, wherein, When measuring an input signal consisting of multiple intervals with different signal levels, the input signal to be measured is distributed to all the input ports. The control unit sets the input level corresponding to each interval to the input port respectively, and the measurement of each interval is performed using the input signal of the input port set with the input level corresponding to each interval.

3. A measurement method, which is a measurement method of a measuring device, the 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 the signal input to the input port by means of the variable attenuator by an attenuation amount corresponding to a set input level, the measurement method comprising the following steps: When measuring an input signal consisting of multiple intervals, each with a different signal level, When measuring each interval, the input level is changed according to the interval being measured.

4. A measurement method, which is a measurement method of a measuring device, the measuring device having 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 by means of the variable attenuators with an attenuation amount corresponding to a set input level, the measurement method comprising the following steps: When measuring an input signal consisting of multiple intervals, each with a different signal level, The input signal that will be measured will be distributed to all the input ports; The input level corresponding to each interval is set at the input port respectively; and Measurements for each interval are performed using input signals from input ports that are configured with input levels corresponding to each interval.

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