Out-of-band useless emission index over-the-air OTA performance test system of wireless equipment
阅读说明:本技术 一种无线设备的带外无用发射指标的空中ota性能测试系统 (Out-of-band useless emission index over-the-air OTA performance test system of wireless equipment ) 是由 宫剑 张明远 付靖 于 2019-10-10 设计创作,主要内容包括:本发明提供了一种无线设备的带外无用发射指标的空中OTA性能测试系统,包括暗室、转台、被测无线设备、信号探测组件、频谱分析仪和控制装置,其中,暗室的路径损耗低于被测无线设备的带外无用发射指标的要求值与频谱分析仪的底噪值之间的差值。本发明采用了具有特定路径损耗值的暗室作为测试场地,通过单个信号探测组件作为探头和可进行水平和竖直旋转的转台配合进行被测无线设备的带外无用发射指标的近场测试,可以有效地保证场地路径损耗和线缆损耗在频谱分析仪上的总体offset补偿值足够小,从而使整个测试系统的底噪可被有效控制,进而获得稳定、良好的带外无用发射指标测试结果,有利于被测无线设备通过指标要求。本测试系统占地面积小、成本低。(The invention provides an over-the-air OTA performance test system of out-of-band useless emission indexes of wireless equipment, which comprises a darkroom, a rotary table, the wireless equipment to be tested, a signal detection assembly, a spectrum analyzer and a control device, wherein the path loss of the darkroom is lower than the difference value between the required value of the out-of-band useless emission indexes of the wireless equipment to be tested and the background noise value of the spectrum analyzer. The invention adopts a darkroom with a specific path loss value as a test field, and performs near field test on the out-of-band useless emission index of the tested wireless equipment by using a single signal detection assembly as a probe and matching with a rotary table capable of horizontally and vertically rotating, so that the total offset compensation value of the field path loss and the cable loss on the spectrum analyzer can be effectively ensured to be small enough, the bottom noise of the whole test system can be effectively controlled, and a stable and good out-of-band useless emission index test result can be obtained, thereby being beneficial to the tested wireless equipment to pass the index requirement. The test system has small floor area and low cost.)
1. An over-the-air OTA performance testing system for out-of-band garbage emission indicators for a wireless device, comprising:
a darkroom;
the rotary table is arranged in the darkroom and is used for rotating in the horizontal and vertical directions under the control of the control device;
the wireless device to be tested is arranged on the rotary table, rotates along with the rotary table and is used for transmitting wireless signals in a specified frequency band;
the signal detection component is arranged in the darkroom and at a preset distance from the wireless device to be detected and is used for receiving a wireless signal transmitted by the wireless device to be detected when the wireless device to be detected rotates;
the spectrum analyzer is connected with the signal detection component and is used for collecting, recording and analyzing the signal from the signal detection component to obtain out-of-band useless emission data of the wireless device to be detected at a preset rotation position; and
the control device is respectively connected with the rotary table and the spectrum analyzer and is used for controlling the rotation of the rotary table, and obtaining an out-of-band useless emission index of the wireless device to be detected according to a preset algorithm based on the out-of-band useless emission data of the wireless device to be detected at a preset rotation position obtained by the spectrum analyzer;
wherein the darkroom has a path loss lower than a difference between a desired value of an out-of-band unwanted emission indicator of the wireless device under test and a background noise value of the spectrum analyzer.
2. The system of claim 1, wherein the wireless device under test is a 5G base station.
3. The system of claim 1, wherein the out-of-band unwanted emission data is an Effective Isotropic Radiated Power (EIRP) of the out-of-band unwanted emissions, and wherein the out-of-band unwanted emission indicator is a Total Radiated Power (TRP) of the out-of-band unwanted emissions.
4. The system of claim 3, wherein the darkroom has a path loss less than or equal to 50 dB.
5. The system of any one of claims 1-4, further comprising:
and the wave trap is arranged on a connecting path of the signal detection assembly and the spectrum analyzer and is used for carrying out frequency filtering on the signal from the signal detection assembly and transmitting the filtered signal to the spectrum analyzer.
6. The system of claim 5, wherein the passband insertion loss of the notch filter is less than or equal to 2 dB;
the stop band rejection of the wave trap is greater than or equal to 80 dB.
7. The system of any of claims 1-4, wherein the spectrum analyzer has a noise floor value of less than or equal to-169 dBm/Hz.
8. The system of claim 1, wherein the signal detection component comprises:
an antenna mount; and
a measuring antenna disposed on the antenna mount;
alternatively, the first and second electrodes may be,
the signal detection assembly includes:
the reflecting surface is arranged opposite to the wireless device to be tested and used for reflecting a wireless signal emitted by the wireless device to be tested when the wireless device to be tested rotates; and
and the feed source antenna is arranged at the focus of the reflecting surface and used for receiving the wireless signal reflected from the reflecting surface and transmitted by the wireless device to be tested.
9. The system of claim 1, wherein the turntable comprises:
a turntable base; and
and the polarization shaft supporting rod is arranged on the rotary table base, and the tested wireless equipment is arranged on the polarization shaft supporting rod.
10. The system of claim 1, wherein the darkroom comprises:
a shield case; and
a wave absorbing material disposed on an inner surface of the shield shell.
Technical Field
The invention relates to the technical field of testing of wireless equipment, in particular to an over-the-air OTA performance testing system with out-of-band useless emission indexes of the wireless equipment.
Background
Currently, although some proposals have been made in relevant international and domestic standards regarding methods for out-of-band unwanted emission OTA (Over the Air) testing of wireless devices, such as 5G base stations, there has been no detailed description of the testing methods to date. Due to the increasing shortage of frequency resources, in order to avoid mutual interference among different systems, the domestic radio administration provides a very strict out-of-band useless transmission OTA test index for wireless transmission equipment (especially a 5G base station below 6 GHz), but does not provide a clear method proposal favorable for passing the test for the strict index.
Disclosure of Invention
In view of the above, the present invention has been developed to provide an over-the-air OTA performance test system for wireless devices that overcomes or at least partially addresses the above-identified problems.
According to an aspect of the embodiments of the present invention, there is provided an over-the-air OTA performance testing system with out-of-band useless emission indicators for wireless devices, including:
a darkroom;
the rotary table is arranged in the darkroom and is used for rotating in the horizontal and vertical directions under the control of the control device;
the wireless device to be tested is arranged on the rotary table, rotates along with the rotary table and is used for transmitting wireless signals in a specified frequency band;
the signal detection component is arranged in the darkroom and at a preset distance from the wireless device to be detected and is used for receiving a wireless signal transmitted by the wireless device to be detected when the wireless device to be detected rotates;
the spectrum analyzer is connected with the signal detection component and is used for collecting, recording and analyzing the signal from the signal detection component to obtain out-of-band useless emission data of the wireless device to be detected at a preset rotation position; and
the control device is respectively connected with the rotary table and the spectrum analyzer and is used for controlling the rotation of the rotary table, and obtaining an out-of-band useless emission index of the wireless device to be detected according to a preset algorithm based on the out-of-band useless emission data of the wireless device to be detected at a preset rotation position obtained by the spectrum analyzer;
wherein the darkroom has a path loss lower than a difference between a desired value of an out-of-band unwanted emission indicator of the wireless device under test and a background noise value of the spectrum analyzer.
Optionally, the wireless device under test is a 5G base station.
Optionally, the out-of-band unwanted emission data is an effective isotropic radiated power EIRP of the out-of-band unwanted emission, and the out-of-band unwanted emission indicator is a total radiated power TRP of the out-of-band unwanted emission.
Optionally, a path loss of the darkroom is less than or equal to 50 dB.
Optionally, the system further comprises:
and the wave trap is arranged on a connecting path of the signal detection assembly and the spectrum analyzer and is used for carrying out frequency filtering on the signal from the signal detection assembly and transmitting the filtered signal to the spectrum analyzer.
Optionally, a passband insertion loss of the trap is less than or equal to 2 dB;
the stop band rejection of the wave trap is greater than or equal to 80 dB.
Optionally, the spectrum analyzer has a noise floor value less than or equal to-169 dBm/Hz.
Optionally, the signal detection assembly comprises:
an antenna mount; and
a measuring antenna disposed on the antenna mount;
alternatively, the first and second electrodes may be,
the signal detection assembly includes:
the reflecting surface is arranged opposite to the wireless device to be tested and used for reflecting a wireless signal emitted by the wireless device to be tested when the wireless device to be tested rotates; and
and the feed source antenna is arranged at the focus of the reflecting surface and used for receiving the wireless signal reflected from the reflecting surface and transmitted by the wireless device to be tested.
Optionally, the turntable comprises:
a turntable base; and
and the polarization shaft supporting rod is arranged on the rotary table base, and the tested wireless equipment is arranged on the polarization shaft supporting rod.
Optionally, the darkroom comprises:
a shield case; and
a wave absorbing material disposed on an inner surface of the shield shell.
The air performance test system of the wireless equipment with the out-of-band useless emission indexes provided by the embodiment of the invention adopts a darkroom with a specific path loss value as a test field, and performs near field test of the out-of-band useless emission indexes of the tested wireless equipment by using a single signal detection assembly as a probe and matching with a turntable which can rotate horizontally and vertically. Because the path loss of the darkroom in the system is lower than the difference value between the required value of the out-of-band useless emission index of the tested wireless equipment and the background noise value of the spectrum analyzer, specifically, less than or equal to 50dB, the total offset compensation value of the field path loss and the cable loss on the spectrum analyzer can be effectively ensured to be small enough, so that the background noise of the whole test system can be effectively controlled, a stable and good out-of-band useless emission index test result is obtained, and the tested wireless equipment can pass the index requirement. Meanwhile, the testing system of the embodiment of the invention has the advantages of small occupied area and low cost due to the adoption of the near-field testing darkroom with the single probe.
Further, the test system provided by the embodiment of the invention further comprises a wave trap arranged on a connecting path of the signal detection assembly and the spectrum analyzer. By selecting a wave trap with specific passband insertion loss (less than or equal to 2dB) and stop band rejection (more than or equal to 80dB), the spectrum analyzer can be effectively ensured to work under the condition of optimal background noise, and the overall offset compensation value on the spectrum analyzer can be further reduced, so that the background noise of the whole system can be controlled to be lower. In addition, a spectrum analyzer with high dynamic range performance (the bottom noise value is less than or equal to-169 dBm/Hz) is matched and selected, so that a better out-of-band useless emission index test result can be obtained.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a block diagram of an over-the-air performance testing system with out-of-band garbage emission indicators for wireless devices according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an over-the-air performance testing system for out-of-band unwanted emission indicators of wireless devices according to another embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Today, relevant international and domestic standards have imposed increasingly stringent pass limit requirements on out-of-band spurious emission OTA test metrics for wireless transmitting devices. Taking the 5G base station as an example, the requirement of the out-of-band useless emission index is more severe than the past, and the limit value of the out-of-band useless emission index is not more than ten or even dozens of dB higher than the actual measurement value as before, so that the actual measurement value of the out-of-band useless emission index of many measured emission systems is quite close to the required limit value or the margin is not high.
The inventor finds that the out-of-band unwanted emission indicator test result is susceptible to the influence of the background noise performance of the test system, so that under the condition that the measured out-of-band unwanted emission indicator values of a plurality of current tested emission systems are quite close to the requirement limit value or the margin is not high, the fluctuation of the measured out-of-band unwanted emission indicator values caused by the background noise of the test system becomes the key for determining whether the test is passed or not. However, no standard and feasible test scheme for the out-of-band useless emission index of the wireless device exists at present, so that the measured out-of-band useless emission index can truly reflect the actual out-of-band useless emission level of the measured wireless device, and the measured wireless device can pass strict index requirements.
To solve the above technical problem, an embodiment of the present invention provides an over-the-air (OTA) performance testing system with out-of-band useless emission indicators for wireless devices.
Fig. 1 shows a schematic structural diagram of an over-the-air
The darkroom (also called anechoic chamber) 7 is a sealed shielded room for radiation measurement. The
The
As shown in fig. 1, the
The
The
The control means 3 may be a means with a built-in control software program, which is connected to the
The OTA performance test system with the out-of-band useless emission indexes of the wireless equipment provided by the embodiment of the invention can be used for testing out-of-band useless emission Total Radiated Power (TRP), stray TRP and the like.
As indicated in the background art, the performance of the background noise (also referred to as background noise) of the test system is crucial to the test result of the out-of-band useless emission indicator, and especially at the present time that the frequency resources are increasingly tight, so that the use condition of the wireless devices in each frequency band is more complicated, the requirements on the out-of-band useless emission indicator of the wireless devices are more severe than before in order to avoid mutual interference and improve compatibility between devices or systems in different frequency bands. In this case, in order to obtain better out-of-band spurious emission test results as much as possible to meet the increasingly stringent specification requirements, controlling the noise floor of the test system becomes the key to determining whether the out-of-band spurious emission test of the wireless device can pass the standard specification requirements. Factors affecting the noise floor of the test system mainly include the path loss of the test site, the dynamic performance of the spectrum analyzer (e.g., the lowest noise floor achievable), and the performance of the trap. In the embodiment of the invention, the path loss of the
The air performance test system of the wireless equipment with the out-of-band useless emission indexes provided by the embodiment of the invention adopts a darkroom with a specific path loss value as a test field, and performs near field test of the out-of-band useless emission indexes of the tested wireless equipment by using a single signal detection assembly as a probe and matching with a turntable which can rotate horizontally and vertically. Because the path loss of the darkroom in the system is lower than the difference value between the required value of the out-of-band useless emission index of the tested wireless equipment and the background noise value of the spectrum analyzer, the total offset compensation value of the field path loss and the cable loss on the spectrum analyzer can be effectively ensured to be small enough, so that the background noise of the whole test system can be effectively controlled, a stable and good out-of-band useless emission index test result is obtained, and the passing of the index requirement of the tested wireless equipment is facilitated. Meanwhile, the testing system of the embodiment of the invention has small occupied area and low cost due to the adoption of the near-field testing darkroom with the single probe.
The following describes the selection of the path loss value of the
When the wireless device under
At present, the limit value of TRP (total radiated power) of the out-of-band useless emission of the 5G base station by domestic and foreign standards is-40 dBm/MHz, which means that the minimum EIRP of each point on a radiation spherical surface of the 5G base station obtained by scanning is ensured to be below-40 dBm/MHz (the single polarization measurement result is-43 dBm/MHz), and the 5G base station to be measured can pass the limit value requirement. At present, the background noise of a general spectrum analyzer can reach-170 dBm/Hz to-160 dBm/Hz, namely-110 dBm/MHz to-100 dBm/MHz under the condition that an internal attenuator is 0 and a preamplifier (or preamplifier) is opened. For the test system provided by the embodiment of the invention, the offset value required to be compensated to the spectrum analyzer during the test comprises field path loss (namely, path loss of darkroom 2) and radio frequency cable loss. It can be found from the calculation that if the background noise of the
In some embodiments, with continued reference to fig. 1, the present invention provides an airborne
When the
TABLE 1
Signal frequency (GHz)
Insertion loss (dB)
2.4835
1.2649
2.50
2.3738
2.515
-74.776
2.675
-89.684
2.70
1.6908
2.90
0.7940
In addition, the stop-band rejection characteristics of the wave trap also influence the TRP test result, and a deeper stop-band rejection degree is more favorable for the test result. The peak EIRP of a 5G base station below 6GHz is generally greater than 74dBm (the maximum peak EIRP can reach more than 77 dBm), and if the stopband rejection of the notch filter is not large enough, a signal entering the spectrum analyzer is large, which may cause that a preamplifier of the spectrum analyzer cannot be turned on, and a built-in attenuator cannot be 0, and in this case, the spectrum analyzer cannot be guaranteed to work under the condition of optimal background noise, and further may cause that the out-of-band OTA test condition for useless TRP emission cannot be satisfied. Therefore, the trap with a larger degree of stop band suppression is more advantageous for the spectrum analyzer to exhibit the best noise suppression capability. For example, for a signal at 2.515GHz, the recommended notch rejection is about 74dB, while for a signal at 2.675GHz, the recommended notch rejection is about 89 dB. Preferably, in the embodiment of the present invention, the stop band rejection of the
In addition, in the out-of-band unwanted emission index test of the 5G base station, the interval between the useful signal of the low frequency band and the unwanted emission signal outside the tested band is only 15MHz, the interval between the useful signal of the high frequency band and the unwanted emission signal outside the tested band is only 25MHz, and the transition from the pass band insertion loss of 2dB to the stop band rejection of 70-80dB needs to be met at the interval, so that higher requirements are provided for the manufacture of a wave trap.
In some embodiments, the
In some embodiments, the aforementioned
Further, with continued reference to fig. 2, the
According to any one or a combination of multiple optional embodiments, the embodiment of the present invention can achieve the following advantages:
the air performance test system of the wireless equipment with the out-of-band useless emission indexes provided by the embodiment of the invention adopts a darkroom with a specific path loss value as a test field, and performs near field test of the out-of-band useless emission indexes of the tested wireless equipment by using a single signal detection assembly as a probe and matching with a turntable which can rotate horizontally and vertically. Because the path loss of the darkroom in the system is lower than the difference value between the required value of the out-of-band useless emission index of the tested wireless equipment and the background noise value of the spectrum analyzer, specifically, less than or equal to 50dB, the total offset compensation value of the field path loss and the cable loss on the spectrum analyzer can be effectively ensured to be small enough, so that the background noise of the whole test system can be effectively controlled, a stable and good out-of-band useless emission index test result is obtained, and the tested wireless equipment can pass the index requirement. Meanwhile, the testing system of the embodiment of the invention has the advantages of small occupied area and low cost due to the adoption of the near-field testing darkroom with the single probe.
Further, the test system provided by the embodiment of the present invention further includes a wave trap disposed on a connection path between the signal detection module and the spectrum analyzer. By selecting a wave trap with specific passband insertion loss (less than or equal to 2dB) and stop band rejection (more than or equal to 80dB), the spectrum analyzer can be effectively ensured to work under the condition of optimal background noise, and the overall offset compensation value on the spectrum analyzer can be further reduced, so that the background noise of the whole system can be controlled to be lower. In addition, a spectrum analyzer with high dynamic range performance (the bottom noise value is less than or equal to-169 dBm/Hz) is matched and selected, so that a better out-of-band useless emission index test result can be obtained.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments can be modified or some or all of the technical features can be equivalently replaced within the spirit and principle of the present invention; such modifications or substitutions do not depart from the scope of the present invention.
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