Intermodulation test equipment

Abstract

The invention provides intermodulation test equipment, which comprises a plurality of signal sources working in different frequency bands, each signal source is used for generating a path of mixed signals, and the downlink frequency band of a first signal source is overlapped with the uplink frequency band of a second signal source; the multiplexer is used for outputting the received one-path or multi-path mixed signal as a test signal to a to-be-tested piece and outputting a reflected signal returned by the to-be-tested piece to the controller, and the multiplexer comprises a broadband interface which at least works in the downlink frequency band and the uplink frequency band; and the multiplexing module is used for being electrically connected with the broadband interface and electrically connected with the first signal source or the controller selectively. According to the intermodulation test equipment, through cooperative work of the multiplexer and the multiplexing module, high-isolation combination of the intermodulation test equipment can be achieved, and the problem that high isolation cannot be achieved when a 800MHz downlink frequency band and a 900MHz uplink frequency band of traditional equipment are overlapped is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mobile communications, and particularly relates to an intermodulation test device. Background Art

[0002] With the rapid development of mobile communication technology, its technology and product forms are constantly updated and iterated. Currently, the technical form of RRU (Remote Radio Unit) has gradually evolved from the traditional single-mode form (such as 700M, 800M, 900M, 1.8G, 2.1G, 2.6G, etc.) to the dual-mode form (such as 1.8 + 2.1G, 700 + 900M, 800 + 900M, etc.) and the triple-mode form (such as 700M + 800M + 900M and 1.8G + 2.1G + 2.6G). Correspondingly, the mainstream FDD RRU of macro base stations is configured with 4TR (four transmit and receive), and the antenna has also developed into a 4-port or multi-port broadband antenna. In this case, a single antenna needs to test the passive intermodulation indicators of multiple ports and multiple frequency bands, which poses higher requirements for the intermodulation test device.

[0003] Most of the ordinary intermodulation test devices on the market currently have functional limitations. Generally speaking, these devices only have single-port and dual-port modes, and the operating frequency band only supports single-band testing, that is, a single intermodulation test device can only test a specific frequency band. For the intermodulation test of multi-frequency multi-port antennas and multi-port passive products, it is often necessary to increase the number of intermodulation test devices, and even one or more intermodulation devices with different frequency bands need to be used. This not only makes the test process cumbersome, but also significantly increases the test cost, and cannot meet the requirement of simultaneous testing of each port.

[0004] To improve the test efficiency, a solution of adopting a multi-port intermodulation test system has been proposed. However, this solution usually builds a test system by means of a switch matrix with multiple intermodulation devices of the same or different frequency bands. Although this system improves the test efficiency to a certain extent, there are still many problems. First, the system structure is complex and huge, with numerous cable connections and complex operations; second, the test cost remains high; in addition, since the intermodulation test system introduces components such as a switch matrix and additional connection cables, it not only increases the output power of a single intermodulation instrument, but also easily affects the test accuracy, thus unable to meet the requirements of high-precision testing.

[0005] In addition, when implementing the centralized procurement of the three frequency bands of 700 MHz, 800 MHz, and 900 MHz, a technical problem is faced, that is, there is an overlap between the downlink frequency band of 800 MHz and the uplink frequency band range of 900 MHz, and it is technically difficult to achieve high isolation combining of these two passbands. The traditional solution is to use the frequency retreat method, that is, to separately narrow the downlink high-end passband of 800 MHz or the receiving channel frequency band range of the uplink of 900 MHz. However, this method has obvious defects. For example, if the 800 MHz frequency band is adjusted back by 5 MHz, the downlink passband of 800 MHz will only be 19 MHz. According to the third-order intermodulation frequency calculation formula 2F1 - F2, its third-order intermodulation products will fall outside the uplink 824 - 849 MHz band, thus unable to meet the requirements of the product intermodulation test and restricting the performance evaluation and quality control of the product.

[0006] Therefore, existing intermodulation test equipment and systems have problems such as low test efficiency, high cost, and poor accuracy when facing the test requirements of multi-frequency and multi-port antennas and passive products, and there is an urgent need for an intermodulation test solution with high efficiency, low cost, and high accuracy. Summary of the Invention

[0007] The primary objective of the present invention is to solve at least one of the above problems and provide an intermodulation test device.

[0008] To meet the various objectives of the present invention, the present invention adopts the following technical solutions:

[0009] To meet one of the objectives of the present invention, an intermodulation test device is provided, including:

[0010] Multiple signal sources operating at different frequency bands, each signal source is used to generate a mixed signal, and the downlink frequency band of the first signal source overlaps with the uplink frequency band of the second signal source;

[0011] A multiplexer, which is used to output one or more received mixed signals as test signals to the device under test, and output the reflected signals returned by the device under test to the controller, and the multiplexer includes a broadband interface, and the broadband interface operates at least in the downlink frequency band and the uplink frequency band;

[0012] A multiplexing module, which is electrically connected to the broadband interface and is selectively electrically connected to the first signal source or the controller.

[0013] In one embodiment, the multiplexer further includes a common interface, the multiplexing module includes a first port, a second port, and a third port, the first port is selectively electrically connected to the second port or the third port, where the first port is electrically connected to the wide-end interface, the second port is electrically connected to the first signal source, the third port and the common interface are electrically connected to the same combiner, and the combiner is also electrically connected to the controller.

[0014] In one embodiment, it further includes a signal cross network and a plurality of the multiplexers. Each signal source is used to generate two carrier signals with different frequencies within the same frequency band. The signal cross network is used to combine the two carrier signals into a mixed wave signal and then divide it into multiple mixed signals. Each multiplexer receives one mixed signal output by the same signal source.

[0015] In one embodiment, the signal cross network is separately provided with a bridge and a power splitter module for each signal source. The bridge is electrically connected to the corresponding signal source and the power splitter module respectively. The bridge is used to combine the two carrier signals output by the signal source into a mixed wave signal, and the power splitter module is used to power split the mixed wave signal output by the bridge into multiple mixed signals.

[0016] In one embodiment, the signal cross network further includes a circulator. Two ends of the circulator are respectively electrically connected to the power splitter module and the multiplexer corresponding to one of the output ports of the power splitter module.

[0017] In one embodiment, the intermodulation test device further includes a signal amplifier, a polling controller, and a digital receiver connected in series in sequence. A combiner is separately configured for each multiplexer, and the multiple combiners are all electrically connected to the signal amplifier. The digital receiver is also electrically connected to the controller.

[0018] In one embodiment, the digital receiver controls the polling controller to perform polling switching to receive the reflected signals output by different multiplexers and poll them to the digital receiver.

[0019] In one embodiment, a power amplifier module is further provided between the signal source and the bridge. The power amplifier module is used to perform power amplification on the carrier signal output from the signal source to the bridge.

[0020] In one embodiment, the signal source includes two signal generators. The two signal generators operate in the same frequency band but generate carrier signals with different frequencies.

[0021] In one embodiment, it includes three signal sources. The operating frequency bands of the three signal sources are 700 MHz, 800 MHz, and 900 MHz respectively. The broadband interface operates simultaneously in the 800 MHz downlink frequency band and the 900 MHz uplink frequency band.

[0022] Compared with the prior art, the present invention has multiple advantages, including but not limited to:

[0023] On the one hand, through the collaborative work of the multiplexer and the multiplexing module, the intermodulation test device of the present invention enables high-isolation combining, solving the problem that traditional devices cannot achieve high isolation when the 800 MHz downlink frequency band and the 900 MHz uplink frequency band overlap. This high-isolation combining ability ensures the accuracy of the test results and meets the requirements of the intermodulation test of the device under test.

[0024] On the other hand, by setting multiple signal sources operating in different frequency bands, the intermodulation test device of the present invention can support the test requirements of multiple frequency bands simultaneously, solving the problem that traditional intermodulation meters can only test a single frequency band. The intermodulation test device of the present invention can complete the intermodulation test of multiple frequency bands, significantly improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the drawings, in which:

[0026] Figure 1 is a circuit principle block diagram of the intermodulation test device of a typical embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0028] Those skilled in the art of the present technology can understand that unless specifically stated otherwise, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more related listed items.

[0029] Those skilled in the art can understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as here.

[0030] The present invention provides an intermodulation test device 100. The intermodulation test device 100 can be provided with a broadband interface in the multiplexer 133 that can simultaneously operate in the downlink frequency band of 800 MHz and the uplink frequency band of 900 MHz, so that the downlink frequency band of 800 MHz and the uplink frequency band of 900 MHz can be multiplexed. In addition, the intermodulation test device 100 has a plurality of multiplexers 133, and each multiplexer 133 can correspond to a test port. It is equivalent to that the intermodulation test device 100 has a plurality of test ports, and each test port can perform intermodulation tests on multiple frequency bands, so that the intermodulation test device 100 can simultaneously perform multi-band intermodulation tests on multiple test pieces, or the intermodulation test device 100 can perform multi-band intermodulation tests on multiple ports of the test piece to improve the intermodulation detection efficiency. The test piece is an external passive device, such as a multi-frequency and / or multi-port antenna, a combiner, a multiplexer, and a coupler.

[0031] In a typical embodiment of the present invention, in combination with Figure 1 , the intermodulation test device 100 includes a controller (not shown), a signal acquisition unit, a signal cross network, a plurality of multiplexers 133, and a plurality of signal sources 120. The controller is electrically connected to the signal acquisition unit, the signal source 120, and the signal cross network respectively, so as to facilitate the controller to control the operation of the intermodulation test device 100.

[0032] The plurality of signal sources 120 operate in different frequency bands respectively, so that the intermodulation test device 100 can perform multi-band intermodulation tests on the test piece. The signal source 120 is used to generate two carrier signals with different frequencies within the same frequency band.

[0033] Specifically, the signal source 120 includes two signal generators 124, and the two signal generators 124 operate within the same frequency band. The controller is electrically connected to the two signal generators 124. The controller controls one of the two signal generators 124 to operate at a first frequency point and controls the other signal generator 124 to operate at a second frequency point, and the first frequency point is different from the second frequency point.

[0034] In one embodiment, the signal source 120 further includes a frequency controller (not shown), which is electrically connected to the controller and two signal generators 124 of the signal source 120 respectively. The controller sends a frequency point control instruction to the frequency controller, and the frequency controller controls the operating frequency points of the signal generators 124 based on the frequency point control instruction, so that the signal generators 124 can correspondingly change the operating frequency points to adapt to different intermodulation test requirements.

[0035] In a typical implementation of the present invention, the signal cross-network includes a plurality of bridges 131 and a plurality of power splitting modules 132. One bridge 131 and one power splitting module 132 are configured corresponding to one signal source 120 in the signal cross-network.

[0036] Specifically, the two signal generators 124 of the signal source 120 are simultaneously electrically connected to the bridge 131, and the two signal generators 124 respectively generate a carrier signal, that is to say, the two signal generators 124 correspondingly generate two carrier signals. The two carrier signals are input into the bridge 131, and the bridge 131 combines the two carrier signals to generate a mixed wave signal.

[0037] In one embodiment, the bridge 131 can be replaced by a combiner (not shown), and the combiner can play the role of the bridge 131. The combiner can combine the two carrier signals output by the two signal generators 124 of the same signal source 120 well.

[0038] In a typical embodiment of the present invention, a power amplifier module 134 is further provided between the signal generator 124 and the bridge 131. The power amplifier module 134 is electrically connected to the signal generator 124 and the bridge 131 respectively. The power amplifier module 134 amplifies the power of the carrier signal output from the signal generator 124, so that the carrier signal can be used for subsequent intermodulation tests.

[0039] The signal cross-network is provided with a power splitting module 132 corresponding to the bridge 131. The power splitting module 132 is electrically connected to the corresponding bridge 131. The bridge 131 outputs the mixed wave signal to the power splitting module 132, and the power splitting module 132 divides the mixed wave signal into multiple signals. To distinguish from the mixed wave signal, the signals generated by the power splitting of the power splitting module 132 are called mixed signals, that is to say, the power splitting module 132 splits the mixed wave signal output by the bridge 131 into multiple mixed signals. For example, the power splitting module 132 splits the mixed wave signal into two mixed signals or three mixed signals or four mixed signals, etc. In one embodiment, the power splitting module 132 can be a power splitter. For example, the power splitting module 132 is a one-to-three power splitter or a one-to-four power splitter, etc., but it should not be construed as a limitation of the present invention.

[0040] In a typical embodiment of the present invention, the power splitting module 132 includes a plurality of power splitters 135. In this embodiment, the power splitter 135 is taken as a one-to-two power splitter 135 as an example to describe the present invention, but it should not be construed as a limitation of the present invention. The hybrid coupler 131 divides the combined hybrid signal into multiple paths, and the number of the multiple hybrid signals corresponds to the number of the corresponding power splitters 135. The hybrid coupler 131 respectively outputs the multiple hybrid signals to the plurality of power splitters 135.

[0041] After receiving a corresponding path of hybrid signal, the power splitter 135 splits the path of hybrid signal into two paths of mixed signals. In this embodiment, the power splitting module 132 can increase the number of the power splitters 135 to increase the number of paths of the mixed signals generated by power splitting the hybrid signal. For example, the power splitting module 132 can be provided with two power splitters 135 to generate four paths of mixed signals, or three power splitters 135 to generate six paths of mixed signals, or four power splitters 135 to generate eight paths of mixed signals... and so on, which will not be elaborated here.

[0042] In this embodiment, the present invention is described by taking the power splitting module 132 as an example with two power splitters 135, but it should not be construed as a limitation of the present invention. It can be understood that the hybrid coupler 131 respectively outputs a path of hybrid signal to each of the two power splitters 135 of the power splitting module 132. Each of the two power splitters 135 splits the input hybrid signal. Each power splitter 135 splits the hybrid signal into two paths of mixed signals, and the two power splitters 135 correspondingly split the two paths of hybrid signals into four paths of mixed signals.

[0043] The signal cross network is provided with a plurality of multiplexers 133. The number of the multiplexers 133 corresponds to the number of paths of the mixed signals generated by power splitting of a power splitting module 132. The multiple paths of mixed signals generated by power splitting of the power splitting module 132 are respectively output to the plurality of multiplexers 133. That is to say, the plurality of signal sources 120 respectively output a path of mixed signal to each multiplexer 133, so that each multiplexer 133 can receive a path of mixed signal output by a plurality of signal sources 120 operating in different frequency bands. Thus, the multiplexer 133 can mix multiple mixed signals in different frequency bands to form a test signal. The multiplexer 133 is electrically connected to the signal port of the device under test. The multiplexer 133 inputs the test signal to the device under test through the signal port of the device under test to perform an intermodulation test on the device under test.

[0044] The multiplexer 133 is provided with a plurality of TX ports (transmission ports), so that the multiplexer 133 can be electrically connected to a plurality of power splitter modules 132 through the plurality of TX ports, facilitating the multiplexer 133 to receive mixed signals of a plurality of different frequency bands. Since the plurality of signal sources 120 respectively operate at different frequency points, the frequency bands of the mixed signals generated by the plurality of signal sources 120 respectively through the corresponding hybrids 131 and the power splitter modules 132 are different, so that the frequency bands of the mixed signals output by the plurality of power splitter modules 132 to the same multiplexer 133 are different.

[0045] In this embodiment, taking the example that the intermodulation test device 100 has three signal sources 120 operating at different frequency bands to describe the present invention, but it should not be construed as a limitation to the present invention. Since the intermodulation test device 100 has three signals operating at different frequency bands, the intermodulation test device 100 can perform third-order and higher-order intermodulation tests, expanding the intermodulation range of the intermodulation test device 100.

[0046] In this embodiment, for the convenience of description, taking the example that the power splitter module 132 includes two power splitters 135 and can split to generate four mixed signals to describe the present invention, but it should not be construed as a limitation to the present invention. The signal cross network is provided with four multiplexers 133, and the four mixed signals generated by splitting the power splitter module 132 are respectively output to the four multiplexers 133.

[0047] In this embodiment, the intermodulation test device 100 is provided with three signal sources 120. The signal cross network separately configures components such as power amplifier modules 134, hybrids 131, and power splitter modules 132 for each signal source 120. Each power splitter module 132 outputs four mixed signals, and the three power splitter modules 132 corresponding to the three signal sources 120 output a total of twelve mixed signals.

[0048] The signal cross network configures three power splitter modules 132 for the three signal sources 120. The three power splitter modules 132 respectively correspond to the three signal sources 120. The three signal sources 120 are respectively called the first signal source 121, the second signal source 122, and the third signal source 123. Among them, the power splitter module corresponding to the first signal source 121 is the first power splitter module 1321, the power splitter module corresponding to the second signal source 122 is the second power splitter module 1322, and the power splitter module corresponding to the third signal source 123 is the third power splitter module 1323.

[0049] Among them, one of the mixed signals output by the first power splitter module 1321 (this mixed signal is called the first mixed signal) is output to the multiplexer 133, one of the mixed signals output by the second power splitter module 1322 (this mixed signal is called the second mixed signal) is output to the multiplexer 133, and one of the mixed signals output by the third power splitter module 1323 (this mixed signal is called the third mixed signal) is output to the multiplexer 133, so that the multiplexer 133 can receive these three mixed signals with different frequency bands.

[0050] When an intermodulation test of a frequency band needs to be performed on the device under test, the controller controls one of the three signal sources 120 to work. Taking the controller controlling the first signal source 121 to work and the second signal source 122 and the third signal source 123 not working as an example, the present invention is described, but it should not be construed as a limitation of the present invention. The controller controls the first signal source 121 to work. The two carrier signals output by the first signal source 121 pass through the power amplifier module 134, the bridge 131 and the first power splitter module 1321 in sequence to generate the first mixed signal. The first mixed signal is output to the multiplexer 133, and the multiplexer 133 outputs the first mixed signal as a test signal to the signal port of the device under test to perform an intermodulation test on the device under test.

[0051] Specifically, since the two signal generators 124 of the first signal source 121 can generate two carrier signals with different frequencies in the same frequency band, when performing an intermodulation test on the device under test, the first signal source 121 controls one of the signal generators 124 (this signal generator is called the first signal generator 1241) to generate a carrier signal with a fixed frequency point (this carrier signal is called the first carrier signal), and the first signal source 121 controls the other signal generator 124 (this signal generator is called the second signal generator 1242) to generate a second carrier signal with a continuously changing frequency point. The first carrier signal and the second carrier signal are combined to generate the first mixed signal. Since the frequency point of the second carrier signal continuously changes, the first mixed signal continuously changes. The continuously changing first mixed signal is used as a test signal and output to the device under test to perform a third-order intermodulation test on the device under test corresponding to the frequency band where the first signal source 121 is located.

[0052] For example, the first signal source 121 operates at 800 MHz, the frequency point of the first carrier signal is fixed at 869 MHz, and the second carrier signal is 894 MHz, but steps down by 1 MHz. The frequency point of the second carrier signal sweeps down from 894, 893, 892... 869 MHz in sequence. The first carrier signal and the second carrier signal are combined to continuously generate different first mixed signals. The multiplexer 133 outputs the first mixed signal as a test signal to the device under test to continuously perform an intermodulation test on the device under test.

[0053] Alternatively, the frequency point of the second carrier signal is fixed at 894 MHz, and the frequency point of the first carrier signal is 869 MHz, but steps upward by 1 MHz. The frequency point of the first carrier signal scans upward from 869, 870, 8871... The first carrier signal and the second carrier signal are combined to continuously generate different first mixed signals. The multiplexer 133 outputs the first mixed signal as a test signal to the device under test to continuously perform intermodulation testing on the device under test.

[0054] Alternatively, when it is necessary to perform intermodulation testing on the device under test by combining two frequency bands, the controller controls two of the three signal sources 120 to work. Taking the controller controlling the first signal source 121 and the second signal source 122 to work and the third signal source 123 not working as an example, the present invention is described, but it should not be construed as a limitation to the present invention. The controller simultaneously controls the first signal source 121 and the second signal source 122 to work. The first signal source 121 generates a first mixed signal through the first power amplifier module 134, and the second signal source 122 generates a second mixed signal through the second power splitter module 1322.

[0055] The multiplexer 133 receives the first mixed signal and the second mixed signal. The multiplexer 133 combines the first mixed signal and the second mixed signal to form a test signal. The multiplexer 133 outputs the test signal to the signal port of the device under test to perform intermodulation testing on the test device.

[0056] It can be seen from this that when the intermodulation test device 100 has three signal sources 120 operating in different frequency bands, a total of four intermodulation test modes can be formed to implement the three-frequency intermodulation function of the intermodulation test device 100. Let the first signal source 121 operate in the first frequency band, the second signal source 122 operate in the second frequency band, and the third signal source 123 operate in the third frequency band. The first frequency band, the second frequency band, and the third frequency band do not overlap. The four intermodulation test modes are respectively: the first frequency band, the second frequency band, the third frequency band, and the intermodulation test in which the first frequency band falls into the uplink frequency band of the second frequency band. For example, here the first frequency band is 700 MHz, the second frequency band is 800 MHz, and the third frequency band is 900 MHz.

[0057] Since the intermodulation test device 100 has multiple multiplexers 133, each multiplexer 133 plays the same role, and each multiplexer 133 generates the same test signal at the same time, so that the multiple multiplexers 133 can correspondingly test multiple test pieces to improve the intermodulation test efficiency. Or, if the test piece has multiple signal ports, the multiple multiplexers 133 of the intermodulation test device 100 are respectively electrically connected to the multiple signal ports of the test piece, so that the intermodulation test device 100 can perform intermodulation tests on the multiple signal ports of the test piece simultaneously to improve the test efficiency of the test piece with multiple ports.

[0058] In an embodiment of the present invention, since the intermodulation test device 100 has four multiplexers 133, the intermodulation test device 100 can perform intermodulation tests by the four multiplexers 133 working simultaneously. In other words, the four multiplexers 133 are equivalent to four test ports of the intermodulation test device 100, and the intermodulation test efficiency is improved through the four test ports. Moreover, since the intermodulation test device 100 has three signal sources 120 operating in different frequency bands, the intermodulation test device 100 constitutes a three-frequency four-port intermodulation test device 100.

[0059] In this embodiment, when the intermodulation test device 100 of the present invention tests a test piece with multiple ports and operating in multiple frequency bands, the number of cable pluggings and unpluggings can be significantly reduced, the intermodulation test efficiency can be improved, and the test time can be reduced.

[0060] For example, when a traditional single-frequency two-port intermodulation tester tests a four-port broadband (700 MHz, 800 MHz, 900 MHz) base station antenna, since each frequency band needs to be tested separately and each port needs to be connected separately, the cable needs to be plugged and unplugged multiple times. Specifically, for a base station antenna with 3 frequency bands and 4 ports, the number of ports to be tested is 3×4 = 12. Each cable needs to be plugged and unplugged twice, with one end of the cable plugged into the intermodulation tester and the other end plugged into the base station antenna. Therefore, the cable needs to be plugged and unplugged 24 times in total.

[0061] However, when using the intermodulation test device 100 of the present invention, since the intermodulation test device 100 of the present invention has four multiplexers 133, which is equivalent to having four test ports, the intermodulation test device 100 of the present invention can connect the 4 ports of the base station antenna at one time and can test 3 frequency bands simultaneously. Thus, only 4 cables need to be connected between the intermodulation test device 100 of the present invention and the base station antenna, and each cable is connected twice, with one end of the cable plugged into the intermodulation test device 100 of the present invention and the other end plugged into the base station antenna. In total, only 8 cable pluggings and unpluggings are needed. Therefore, the number of cable pluggings and unpluggings is reduced from 24 times to 8 times, the efficiency is increased by 3 times, and the test time is also reduced by more than half.

[0062] Thus, the intermodulation test device 100 of the present invention completely changes the cumbersome process of replacing intermodulation meters with different frequency bands for multiple tests in traditional intermodulation tests, greatly reduces the number of cable pluggings and unpluggings, effectively reduces the loss of expensive intermodulation test cables, and also reduces the requirement for anechoic chambers in intermodulation tests, further significantly reducing the overall cost of intermodulation tests.

[0063] In a typical embodiment of the present invention, the intermodulation test device 100 having three signal sources 120 operating in different frequency bands and four multiplexers 133 is taken as an example for illustration, but this should not be regarded as a limitation to the present invention. After understanding the technical solution of the present invention, those skilled in the art can adaptively increase the number of signal sources 120 operating in different frequency bands and the number of multiplexers 133 to expand the application scope of the intermodulation test device 100. These technical solutions that can be achieved without creative labor based on the present invention all fall within the protection scope of the present invention. For example, on the basis that the intermodulation test device 100 has three signal sources 120 operating in different frequency bands and four multiplexers 133, one more signal source 120 operating in a different frequency band and one more multiplexer 133 are further added, so that the intermodulation test device 100 has four signal sources 120 operating in different frequency bands and five multiplexers 133.

[0064] In one embodiment, the signal cross network is provided with a plurality of circulators 136 corresponding to one multiplexer 133. The plurality of circulators 136 are arranged corresponding to the plurality of TX ports of the multiplexer 133. The mixed wave signals respectively input from the plurality of power splitting modules 132 to the multiplexer 133 need to pass through the corresponding circulators 136 first and then are input to the multiplexer 133 through the corresponding TX ports. The circulator 136 is used to isolate the mixed wave signals transmitted from the power splitting module 132 to the multiplexer 133 to block reverse signal interference, reduce signal distortion and interference, and improve the accuracy of intermodulation tests.

[0065] Furthermore, during the intermodulation test, the standing wave ratio of the device under test significantly affects the intermodulation test accuracy. The standing wave ratio is an indicator to measure the matching degree between an antenna or a transmission line and a load. When the standing wave ratio is large (for example, greater than 1.5), it will cause uneven power distribution among the shunt channels of the power splitter module 132, thereby affecting the test accuracy. The intermodulation test device 100 realizes the simultaneous transmission of test signals by all multiplexers 133 through power splitting. However, if the standing wave ratio of the signal port of a device under test in the intermodulation test is high, that is, there is a large reflection, it will affect the power distribution of each multiplexer 133, resulting in unstable output power of each multiplexer 133 and unable to perform accurate tests. To solve this problem, in the present invention, a circulator 136 corresponding to the frequency band is connected in series before the TX port of the multiplexer 133. The circulator 136 can withstand power reflection for a short time, thereby ensuring that the power of each multiplexer 133 is equal and solving the test accuracy problem when the port is adapted or open-circuited.

[0066] In a typical embodiment of the present invention, the signal acquisition unit of the intermodulation test device 100 includes a signal amplifier 141, a polling controller 142, and a digital receiver 143. The multiplexer 133 further includes an RX port (reception port). After the multiplexer 133 outputs a test signal to the device under test to perform an intermodulation test, the device under test will generate a reflected signal. The multiplexer 133 receives the reflected signal, and the multiplexer 133 outputs the reflected signal to the signal amplifier 141 through the RX port. The signal amplifier 141 amplifies the power of the reflected signal. Then, the signal amplifier 141 outputs the reflected signal to the digital receiver 143 through the polling controller 142. After receiving the reflected signal, the digital receiver 143 transmits the reflected signal to the controller, and the controller generates test data based on the reflected signal, thereby obtaining the intermodulation test data of the device under test.

[0067] Specifically, the multiple multiplexers 133 share the same signal amplifier 141, or each multiplexer 133 is respectively configured with a signal amplifier 141. In this embodiment, the multiple multiplexers 133 share the same polling controller 142. After the reflected signals output by the multiple multiplexers 133 are output through the corresponding signal amplifiers 141, they are output to the polling controller 142.

[0068] The digital receiver 143 is used to control the operation of the polling controller 142, so that the polling controller 142 polls and receives the reflected signals output by a plurality of multiplexers 133. That is to say, under the control of the digital receiver 143, the polling controller 142 only receives the reflected signal output by one multiplexer 133 at a time through time-division multiplexing, so as to avoid the mixing and interference of the reflected signals output by the plurality of multiplexers 133. In this embodiment, it is recommended that the polling controller 142 be a single-pole multi-throw electronic switch, but it should not be construed as a limitation of the present invention.

[0069] The polling controller 142 outputs the reflected signals received at different times to the digital receiver 143, and the digital receiver 143 converts the reflected signals into digital signals, so as to facilitate the controller to analyze the digital signals and obtain the intermodulation test data of the specimen to be tested. In this embodiment, the digital receiver 143 converts signal characteristics such as the amplitude, frequency, and phase of the reflected signal into digital signals. For example, through steps such as analog-to-digital conversion, down-conversion, quadrature demodulation, and digital signal processing, accurate measurement and analysis of the reflected signal are realized. The digital signal provides an accurate data basis for the subsequent analysis of the controller, so as to facilitate the generation of accurate test data. In this embodiment, it is recommended that the controller be a computer, but it should not be construed as a limitation of the present invention.

[0070] In a typical implementation of the present invention, the first signal source 121 operates in a first frequency band, and the second signal source 122 operates in a second frequency band, where the downlink frequency band of the first frequency band overlaps with the uplink frequency band of the second frequency band. For example, the first frequency band is 800 MHz, and the downlink frequency band of the first frequency band is 869 MHz - 894 MHz; the second frequency band is 900 MHz, and the uplink frequency band of the second frequency band is 880 MHz - 915 MHz; the downlink frequency band and the uplink frequency band have an overlapping frequency band of 880 MHz - 894 MHz.

[0071] Therefore, one of the interfaces of the multiplexer 133 is made into a broadband interface 1331, and the broadband interface 1331 operates at least in the downlink frequency band and the uplink frequency band. The intermodulation test device 100 also separately configures a multiplexing module 160 for the multiplexer 133. The multiplexing module 160 has three ports, which are a first port 161, a second port 162, and a third port 163 respectively. The first port 161 is electrically connected to the broadband interface 1331 of the corresponding multiplexer 133, the second port 162 is electrically connected to one of the output ports of the first power splitting module 1321, and the third port 163 is electrically connected to the signal amplifier 141. In this embodiment, it is recommended that the multiplexing module 160 be a multiplexing switch, preferably a single-pole double-throw electronic switch, but it should not be construed as a limitation of the present invention.

[0072] The controller controls the multiplexing module 160 to work, so that the first port 161 of the multiplexing module 160 is selectively electrically connected to the second port 162 or the third port 163. It can be understood that when the first port 161 is electrically connected to the second port 162 and the first port 161 is not electrically connected to the third port 163, the broadband interface 1331 can receive the first mixed signal output by the first power splitting module 1321 from the first signal source 121. Further, the first power splitting module 1321 can output the first mixed signal including one of the frequency points in the downlink frequency band to the broadband interface 1331. Then, the multiplexer 133 outputs the first mixed signal as a test signal to the device under test for intermodulation testing.

[0073] When the first port 161 is electrically connected to the third port 163 and the first port 161 is not electrically connected to the second port 162, the first power splitting module 1321 can no longer output the first mixed signal including one of the frequency points in the downlink frequency band to the broadband interface 1331, making the broadband interface 1331 in an idle state. The second signal source 122 can output the second mixed signal including one of the frequency points in the uplink frequency band to the multiplexer 133 through the second power splitting module 13224. Then, the multiplexer 133 outputs the second mixed signal as a test signal to the device under test for intermodulation testing.

[0074] The device under test responds to the second mixed signal and returns a corresponding reflected signal (referred to as the second reflected signal) to the multiplexer 133. The frequency of the second reflected signal is the same as that of the second mixed signal, that is to say, the second reflected signal also includes the frequency points in the downlink frequency band corresponding to the second mixed signal. Since the broadband interface 1331 of the multiplexer 133 also operates in the downlink frequency band and is in an idle state, the second reflected signal can pass through the broadband interface 1331, then through the first port 161 and the third port 163 of the multiplexing module 160, and is output to the signal amplifier 141.

[0075] Thus, with the cooperation of the multiplexing module 160, the broadband interface 1331 of the multiplexer 133 can be multiplexed by the downlink frequency band of the first frequency band and the uplink frequency band of the second frequency band, so that the intermodulation test equipment 100 can arrange the uplink frequency band and the downlink frequency band at the same time to expand the intermodulation test range of the intermodulation test equipment 100.

[0076] In one embodiment, the multiplexer 133 is further provided with a common interface 1332, and the common interface 1332 can be used to receive reflected signals of frequency bands other than the downlink frequency band. Moreover, the intermodulation test device 100 also separately configures a combiner 170 for the multiplexer 133. The third port 163 of the multiplexing module 160 and the common interface 1332 are both electrically connected to the combiner 170, and the combiner 170 is also electrically connected to the signal amplifier 141.

[0077] When the intermodulation test device 100 performs an intermodulation test by combining two frequency bands, and one of the frequency bands includes the downlink frequency band, the mixed signals corresponding to the two frequency bands are mixed to form a test signal, and the test signal is output to the device under test for intermodulation testing. The reflected signal returned by the device under test can be divided into a first path signal including the downlink frequency band and a second path signal not including the downlink frequency band. The first path signal is output to the combiner 170 through the broadband interface 1331, and the second path signal is output to the combiner 170 through the common interface 1332. The combiner 170 then combines the first path signal and the second path signal into the reflected signal, and then outputs the reflected signal to the digital receiver 143.

[0078] In one embodiment, the intermodulation test device 100 further includes a local oscillator source 145, and the local oscillator source 145 is electrically connected to the polling controller 142 or the signal amplifier 141. When the controller controls the intermodulation test device 100 to generate a high-frequency test signal, the device under test will correspondingly return a high-frequency reflected signal. Since the frequency of the high-frequency reflected signal is relatively high, it is difficult to directly process these high-frequency signals.

[0079] For this reason, the controller controls the local oscillator source 145 to generate a local oscillator signal, and mixes the local oscillator signal with the high-frequency reflected signal received by the polling controller 142 or the signal amplifier 141 to convert the high-frequency reflected signal into an intermediate-frequency signal, thereby reducing the frequency of the reflected signal and making it easier for the subsequent digital receiver 143 to perform digital processing on the intermediate-frequency signal.

[0080] In one embodiment, the intermodulation test device 100 further includes a reference source interface (not shown), and the reference source interface is used to be electrically connected to an external reference source. The reference source interface is disposed on the controller, and the controller provides a high-precision clock signal for the intermodulation test device 100 based on the reference source to ensure the frequency stability of multiple signal sources 120 and the local oscillator source 145 of the intermodulation test device 100, and improve the test accuracy of the intermodulation test device 100.

[0081] In this embodiment, the reference source is a temperature-compensated crystal oscillator (TCXO) or an oven-controlled crystal oscillator (OCXO). In this embodiment, it is recommended that the reference source be an oven-controlled crystal oscillator, and the frequency accuracy and long-term frequency stability of the oven-controlled crystal oscillator are at least several orders of magnitude higher than those of a general temperature-compensated crystal oscillator. Using an oven-controlled crystal oscillator as the reference source can significantly improve the phase noise performance of the signal source 120, reduce carrier spurs, and thus improve the overall performance of the intermodulation test device 100.

[0082] In one embodiment, the intermodulation test device 100 further includes a first housing 151 and a second housing 152. The signal source 120, the digital receiver 143, the polling controller 142, and the local oscillator 145 are installed in the first housing 151, and the signal crossover network and the multiplexer 133 are installed in the second housing 152. Components such as the signal source 120 and the digital receiver 143 generate electromagnetic radiation during operation, while the signal crossover network is vulnerable to external interference or becomes a radiation source. Placing them in different housings can reduce electromagnetic interference between different components and improve the electromagnetic compatibility of the device. In addition, installing different functional modules in different housings helps to achieve modularization and integration of functions. Components such as the signal source 120, the digital receiver 143, the polling controller 142, and the local oscillator 145 are mainly responsible for signal generation, reception, and processing, while the signal crossover network is responsible for signal distribution and routing. By installing them in different housings respectively, it is possible to better achieve functional partitioning and integration.

[0083] In a typical embodiment of the present invention, the intermodulation test device 100 is further provided with a display screen (not shown). The controller is electrically connected to the display screen, and the controller can output the intermodulation test data of the test piece to be tested to the display screen for display, so that the user can directly obtain the test data of the test piece through the display screen.

[0084] In one embodiment, the controller is further provided with a communication interface (not shown). The controller performs data communication with an external control device through the communication interface. Specifically, the controller submits test data to the external control device through the communication interface, and at the same time, the controller can also receive test instructions output by the external control device through the communication interface. Based on the test instructions, the controller can control the working state and test process of the intermodulation test device 100, enabling the intermodulation test device 100 to perform effective data interaction and instruction control with the external control device, improving the automation degree and test efficiency of the device. For example, during third-order intermodulation testing, the controller can accurately control the output frequency and power of the signal source 120 according to the instructions of the external control device, so as to achieve testing of different frequency bands and different power combinations.

[0085] In addition, the communication interface can also be used to receive test instructions output by an external control device, enabling the controller to control the operation of the intermodulation test device 100 based on the test instructions, further improving the flexibility and efficiency of the test. In this embodiment, it is recommended that the communication interface support multiple interfaces such as LAN, USB, and GBIP, and be compatible with the SCPI standard protocol, ensuring unobstructed data interaction with various programming languages.

[0086] In summary, the intermodulation test device of the present invention has multiple test ports and multiple test frequency bands, enabling the intermodulation test device to simultaneously perform third-order or higher-order intermodulation tests on multiple test pieces to be tested or multiple signal ports of the same test piece to be tested, thereby improving the intermodulation test efficiency.

[0087] The above description is only a preferred embodiment of the present invention and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solution formed by the specific combination of the above technical features. At the same time, it should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with (but not limited to) technical features having similar functions in the present invention.

[0088] Although the subject matter has been described in language specific to structural features and / or methodological act logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. On the contrary, the specific features and acts described above are merely example forms for implementing the claims.

Claims

1. An intermodulation test device, characterized in that: include: A plurality of signal sources operating in different frequency bands, each signal source being used to generate a mixed signal, wherein a downlink frequency band of a first signal source overlaps an uplink frequency band of a second signal source; A multiplexer, used to output one or more received mixed signals as test signals to the device under test, and output the reflected signal returned by the device under test to the controller, and the multiplexer includes a broadband interface, and the broadband interface works at least in the downlink frequency band and the uplink frequency band; The multiplexing module is used to be electrically connected to the broadband interface and selectively electrically connected to the first signal source or the controller.

2. The intermodulation test equipment according to claim 1, characterized in that: The multiplexer also includes a common interface, and the multiplexing module includes a first port, a second port and a third port, the first port is electrically connected to the second port or the third port, wherein the first port is electrically connected to the wide-end interface, the second port is electrically connected to the first signal source, the third port and the common interface are electrically connected to the same combiner, and the combiner is also electrically connected to the controller.

3. The intermodulation test equipment as claimed in claim 2, characterized in that: It also includes a signal crossing network and a plurality of the multiplexers, each signal source is used to generate two carrier signals with different frequencies in the same frequency band, the signal crossing network is used to combine the two carrier signals into a mixed signal, and then divide them into multiple mixed signals, and each multiplexer receives a mixed signal output by the same signal source.

4. The intermodulation test equipment as claimed in claim 3, characterized in that: The signal cross network is provided with a bridge and a power division module corresponding to each signal source. The bridge is electrically connected to the corresponding signal source and the power division module respectively. The bridge is used to combine the two carrier signals output by the signal source into a mixed signal, and the power division module is used to power divide the mixed signal output by the bridge into multiple mixed signals.

5. The intermodulation test equipment according to claim 4, characterized in that: The signal cross network further comprises a circulator, and two ends of the circulator are respectively electrically connected to the power division module and a multiplexer corresponding to one of the output ports of the power division module.

6. The intermodulation test equipment according to claim 2, characterized in that: The intermodulation test equipment also includes a signal amplifier, a polling controller and a digital receiver connected in series in sequence. A combiner is separately configured for each multiplexer. The multiple combiners are all electrically connected to the signal amplifier, and the digital receiver is also electrically connected to the controller.

7. The intermodulation test equipment according to claim 6, characterized in that: The digital receiver controls the polling controller to perform polling switching so as to receive the reflected signals output by different multiplexers and output them to the digital receiver in a polling manner.

8. The intermodulation test equipment according to claim 4, characterized in that: A power amplifier module is also provided between the signal source and the bridge, and the power amplifier module is used to amplify the carrier signal output from the signal source to the bridge.

9. The intermodulation test equipment according to claim 3, characterized in that: The signal source includes two signal generators, which work in the same frequency band but generate carrier signals with different frequencies.

10. The intermodulation test equipment according to any one of claims 1 to 9, characterized in that: It comprises three signal sources, the working frequency bands of the three signal sources are 700MHz, 800MHz and 900MHz respectively, and the broadband interface works simultaneously in the downlink frequency band of 800MHz and the uplink frequency band of 900MHz.

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