English:
[0001] The present invention relates to testing of a radio frequency (RF) data packet signal transceiver, and in particular, to testing such a device via a wireless signal path.
[0002] Many of today's electronic devices use wireless signal technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless signal technologies must adhere to various wireless signal technology standard specifications.
[0003] When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless signal technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless signal technology standard-based specifications.
[0004] For testing these devices following their manufacture and assembly, current wireless device test systems typically employ testing subsystems for providing test signals to each device under test (DUT) and analyzing signals received from each DUT. Some subsystems (often referred to as "testers") include at least a vector signal generator (VSG) for providing the source signals to be transmitted to the DUT, and a vector signal analyzer (VSA) for analyzing signals produced by the DUT. The production of test signals by the VSG and signal analysis performed by the VSA are generally programmable (e.g., through use of an internal programmable controller or an external programmable controller such as a personal computer) so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless signal technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
[0005] During manufacturing, the testing of such wireless devices (i.e., prior to full assembly including the system housing, or case, and antenna system, which can involve one or more antennas depending upon modes of wireless operations) typically involves conveyance of test signals between the tester and DUT via conductive signal paths, such as RF cabling and connectors (e.g., coaxial). Later, after full assembly, further tests are typically performed to make sure that the antenna system and connections (signals and power) are operating properly and that no other post-assembly defects (e.g., electronic, mechanical or electro-mechanical) have occurred.
[0006] Proper operation of a fully assembled DUT can be determined by a combination of DUT receiver and transmitter tests where the receiver sensitivity (e.g., measured in terms of bit error rate (BER) or packet error rate (PER), defined as the number of incorrectly received data bits or packets divided by the total number of transmitted bits or packets, respectively) is better (i.e., lower) than a specified value, and transmitter power output is found to be within a desired power range. However, determining receiver sensitivity and/or transmitter output power accurately in a wireless test environment (e.g., a testing environment involving radiative conveyance of test signals between the tester and DUT) tends to be problematic due to sensitivity of the positioning of the DUT within the test environment caused by variables associated with distances between the tester and DUT antennas, such as signal attenuation and multipath effects.
[0007] To avoid these testing issues, while conductive signal paths could be used, such testing techniques cannot be used to include effects from wireless signal issues associated with antenna systems and connections.
[0009] In accordance with the presently claimed invention, a method is provided for testing a radio frequency (RF) data packet signal transceiver device under test (DUT) via a wireless signal medium that enables final functional testing of a fully assembled DUT without requiring wired signal connections. System performance characteristics indicative of manufacturing assembly defects, such as defective antennas or subsystem connections, can be performed using over the air (OTA) test signals communicated wirelessly between the DUT and a tester. By using actual DUT performance characteristics determined during earlier manufacturing tests, such as receiver sensitivity and transmitter power, and known power levels available from the tester transmitter, the OTA signal path loss (i.e., attenuation of the wireless signal) can be estimated and used to confirm the final state of system operation.
[0010] In accordance with one embodiment of the presently claimed invention, a method for testing a radio frequency (RF) data packet signal transceiver device under test (DUT) via a wireless signal path includes:
[0011] transmitting, from a tester via a wireless signal path, a tester data packet signal including a plurality of tester data packets and having a transmitted tester data packet signal power as transmitted from the tester;
[0012] receiving, with the tester from a DUT via the wireless signal path, a DUT data packet signal including a plurality of DUT data packets and having a received DUT data packet signal power as received at the tester;
[0013] repeating the transmitting and receiving of the tester and DUT data packet signals while altering the transmitted tester data packet signal power to another transmitted tester data packet signal power at which a ratio of the pluralities of DUT and tester data packets substantially equals a predetermined ratio value related to a receiver sensitivity power of the DUT;
[0014] computing a wireless signal path loss of the wireless signal path related to a difference between the another transmitted tester data packet signal power and the receiver sensitivity power; and
[0015] following reception with the tester of the DUT data packet signal, comparing at least one sum of the received DUT data packet signal power and the wireless signal path loss with an expected transmitted DUT data packet signal power.
[0016] In accordance with another embodiment of the presently claimed invention, a method for testing a radio frequency (RF) data packet signal transceiver device under test (DUT) via a wireless signal path includes:
[0017] receiving, with a DUT from a tester via a wireless signal path, a tester data packet signal including a plurality of tester data packets and having a transmitted tester data packet signal power as transmitted from the tester;
[0018] transmitting, with the DUT via the wireless signal path, a DUT data packet signal including a plurality of DUT data packets and having a received DUT data packet signal power as received at the tester;
[0019] repeating the receiving and transmitting of the tester and DUT data packet signals with the received tester data packet signal having another transmitted tester data packet signal power at which a ratio of the pluralities of DUT and tester data packets substantially equals a predetermined ratio value related to a receiver sensitivity power of the DUT;
[0020] computing a wireless signal path loss of the wireless signal path related to a difference between the another transmitted tester data packet signal power and the receiver sensitivity power; and
[0021] following transmission with the DUT of the DUT data packet signal, comparing at least one sum of the received DUT data packet signal power and the wireless signal path loss with an expected transmitted DUT data packet signal power.
[0022] In accordance with another embodiment of the presently claimed invention, a method for testing a radio frequency (RF) data packet signal transceiver device under test (DUT) via a wireless signal path includes:
[0023] transmitting, from a tester via a wireless signal path, a tester data packet signal including a plurality of tester data packets and having a transmitted tester data packet signal power as transmitted from the tester;
[0024] receiving, with the DUT via the wireless signal path, the tester data packet signal;
[0025] transmitting, with the DUT via the wireless signal path, a DUT data packet signal including a plurality of DUT data packets;
[0026] receiving, with the tester via the wireless signal path, the DUT data packet signal having a received DUT data packet signal power as received at the tester;
[0027] repeating the transmitting and receiving of the tester and DUT data packet signals while altering the transmitted tester data packet signal power to another transmitted tester data packet signal power at which a ratio of the pluralities of DUT and tester data packets substantially equals a predetermined ratio value related to a receiver sensitivity power of the DUT;
[0028] computing a wireless signal path loss of the wireless signal path related to a difference between the another transmitted tester data packet signal power and the receiver sensitivity power; and
[0029] following reception with the tester of the DUT data packet signal, comparing at least one sum of the received DUT data packet signal power and the wireless signal path loss with an expected transmitted DUT data packet signal power.
[0030] Figure 1 depicts an exemplary performance curve of a DUT in terms of error rate percentage versus received signal power (e.g., BER or PER).
[0031] Figure 2 depicts a wireless signal testing environment in which the implicit loss of the wireless signal path between the tester and DUT can be determined.
[0032] Figure 3 depicts data packet signals exchanged between the tester and DUT.
[0033] Figure 4 depicts use of such wireless testing environment where testing reveals satisfactory receiver sensitivity and transmitter output power.
[0034] Figure 5 depicts use of such a wireless testing environment where testing reveals a defect in receiver sensitivity.
[0035] Figure 6 depicts a use of such a wireless testing environment where testing reveals a defect in transmitter output power.
[0036] Figure 7 depicts use of such a wireless testing environment where testing reveals a defect in the integrity of the antenna system.
[0037] The following detailed description is of example embodiments of the presently claimed invention with references to the accompanying drawings. Such description is intended to be illustrative and not limiting with respect to the scope of the present invention. Such embodiments are described in sufficient detail to enable one of ordinary skill in the art to practice the subject invention, and it will be understood that other embodiments may be practiced with some variations without departing from the spirit or scope of the subject invention.
[0038] Throughout the present disclosure, absent a clear indication to the contrary from the context, it will be understood that individual circuit elements as described may be singular or plural in number. For example, the terms "circuit" and "circuitry" may include either a single component or a plurality of components, which are either active and/or passive and are connected or otherwise coupled together (e.g., as one or more integrated circuit chips) to provide the described function. Additionally, the term "signal" may refer to one or more currents, one or more voltages, or a data signal. Within the drawings, like or related elements will have like or related alpha, numeric or alphanumeric designators. Further, while the present invention has been discussed in the context of implementations using discrete electronic circuitry (preferably in the form of one or more integrated circuit chips), the functions of any part of such circuitry may alternatively be implemented using one or more appropriately programmed processors, depending upon the signal frequencies or data rates to be processed. Moreover, to the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry.
[0039] Wireless devices, such as cellphones, smartphones, tablets, etc., make use of standards-based technologies (e.g., IEEE 802.11a/b/g/n/ac, 3GPP LTE, and Bluetooth). The standards that underlie these technologies are designed to provide reliable wireless connectivity and/or communications. The standards prescribe physical and higher-level specifications generally designed to be energy-efficient and to minimize interference among devices using the same or other technologies that are adjacent to or share the wireless spectrum.
[0040] Tests prescribed by these standards are meant to ensure that such devices are designed to conform to the standard-prescribed specifications, and that manufactured devices continue to conform to those prescribed specifications. Most devices are transceivers, containing at least one or more receivers and transmitters. Thus, the tests are intended to confirm whether the receivers and transmitters both conform. Tests of the receiver or receivers (RX tests) of a DUT typically involve a test system (tester) sending test packets to the receiver(s) and some way of determining how the DUT receiver(s) respond to those test packets. Transmitters of a DUT are tested by having them send packets to the test system, which then evaluates the physical characteristics of the signals sent by the DUT.
[0041] In accordance with exemplary embodiments of the presently claimed invention, as discussed in more detail below, it is possible to determine whether manufacturing and/or assembly defects have occurred that affect receiver sensitivity or transmitter power performance of a DUT without requiring that absolute signal path loss in a wireless testing environment be first determined. As will be readily appreciated by one of ordinary skill in the art, testing of a partially assembled DUT using conductive signal paths will have ensured satisfactory receiver signal sensitivity. Such measured sensitivity should not be affected or otherwise change as a result of full assembly of the DUT, and should serve as a reference point for later use. This should generally hold true since final assembly should not affect any active circuitry of the DUT, and only passive devices typically exist outside of such active circuitry.
[0042] Then, following full assembly of the DUT, the receiver sensitivity can be tested by providing a tester signal with a power level reduced to that which produces a known or prescribed error rate (e.g., a 50% PER), which was determined during manufacturing tests. Further, as discussed in more detail below, this also enables measurement of DUT transmitted power based on the responsive data packets (e.g., acknowledgment (ACK) data packets) transmitted by the DUT during testing of its sensitivity.
[0043] Referring to Figure 1, the 50% PER point is preferably used as the typical PER curve of a DUT has its maximum slope at this point, thereby making it less sensitive to statistical variations. Further, it enables easier iterative algorithms, thereby enabling faster testing. (See, for example, US Patent Application Number 13/959354, entitled "Method for Testing Sensitivity of a Data Packet Signal Transceiver", incorporated herein by reference.) Of course, PER points other than 50% can also be used for purposes of determining whether the measured PER point is less than or greater, as well as for defining the DUT receiver sensitivity, i.e., the minimum level of signal detected by the receiver to guarantee that a specified maximum receive PER is not exceeded.
[0044] As discussed in more detail below, the difference between the radiated power level of the signal transmitted by the tester and the previously measured DUT receiver sensitivity power level (the reference point) accounts for implicit losses (including signal path loss) within the wireless signal test environment. As noted, this implicit loss will be substantially the same for signals conveyed from the DUT to the tester as well, provided the positioning of the DUT relative to the tester remains consistent within the wireless testing environment and the tester and DUT transmitted signals are transmitted at the same frequency, or within a relatively narrow frequency range. (As will be readily appreciated, any potential frequency range over which results can be expected to be reasonably consistent will be dependent upon the degree to which signal phases of respective frequency components are affected by the wireless signal environment.)
[0045] As a result, once this implicit loss figure has been determined, it can be used with the expected receiver sensitivity figure for the DUT receiver test signals and the expected DUT output power signal levels for DUT transmitter signals for purposes of confirming receiver and transmitter signal performance and path integrity. As discussed in more detail below, by determining how these figures differ from those which are expected, it can be determined if the failure is due to manufacturing or assembly-related defects in the receive or transmit signal paths of the DUT (e.g., reduction in DUT receiver sensitivity or issues with the antenna system or connections).
[0046] Referring to Figure 2, a wireless signal testing environment for performing tests in accordance with exemplary embodiments of the presently claimed invention includes a tester 10 and DUT 20 separated by a wireless signal path 30. (As will be readily appreciated, this testing environment can be expanded as desired to include multiple DUTs for testing multiple DUTs simultaneously or serially.) The tester 10 typically includes (or has remote access to and control over) a test signal source, e.g., a VSG 12, and a test signal analysis system, e.g., a VSA 14, as noted above. The tester 10 also includes an antenna system 16 including an antenna 16a (which, alternatively, may include multiple antenna elements) and antenna connection 16b (e.g., a threaded co-axial RF signal connector as is commonly known and used in the art) for and electrically connecting (and, often, mechanically securing) the antenna 16a to the tester 10 and circuitry within the tester 10. Test signals from the signal source 12 are radiated by the antenna system 16 as wireless signals 17 for reception by the DUT 20.
[0047] Similarly, the DUT 20 includes an antenna system 26 having one or more antenna elements 26a and antenna connections 26b. This antenna system 26 radiates wireless DUT signals 27 from the DUT 20 for reception by the tester 10.
[0048] Also included, though not shown here, is a controller, such as a personal computer, which contains and executes a test program for controlling the tester 10 in such a manner as to cause the internal signal source 12 to provide appropriate test signals for reception by the DUT 20, and control the internal signal analysis system 14 for receiving and analyzing signals received from the DUT 20.
[0049] Alternatively, the tester 10 and/or the DUT 20 can be pre-programmed with test commands and responses for performing testing in response to wireless signals exchanged between the tester 10 and DUT 20 via the wireless signal path 30 with no, or little, external control. Such testing techniques are described in U.S. Patent No. 7,689,213 and U.S. Patent No. 8,811,194, incorporated herein by reference.
[0050] During testing, the tester will have a signal output power provided to the antenna system 16 having a known power level Poutequal to a predetermined or programmed power level P2. The DUT 20 will have a known receiver sensitivity P50 determined during manufacturing test (e.g., the received signal power level at which the packet error rate of the DUT is 50% as discussed above). The implicit loss is primarily the signal path loss of the wireless signal path 30 between the tester and the DUT and can be computed by finding the difference P2-P50 between the tester power level P2and the receiver sensitivity level P50. (As will be readily appreciated, while this computation is not exact, it is a good estimation. Even if the exact sensitivity value is unknown, (e.g, only PER is being measured), it is nonetheless known that the sensitivity will be within a narrow range defined as between the PER test point and a lower bound established by the inherent noise figure of the DUT receiver.)
[0051] Because of signal path loss symmetry, as discussed above, this implicit loss will also be experienced by signals 27 transmitted from the DUT 20 to the tester 10. The power level of the DUT signal 27 as received at the tester 10 (e.g., as measured by the VSA 14) can be used to extrapolate the output power level of the signal 27 transmitted by the DUT 20 by adding this implicit loss Pout=Pin+IL. (This can be confirmed by controlling or programming the DUT 20 to transmit its signals 27 at multiple predetermined power levels and extrapolating the output power level for each measurement.)
[0052] Referring to Figure 3, in accordance with well-known systems and principals, wireless data packet transceiver systems are tested by transmitting data packet signals 17 from the tester to which the DUT responds by sending responsive data packets 27 (e.g., ACK data packets). Accordingly, the tester 10 will transmit a sequence of test data packets 17a, 17b, 17c, 17d, to which the DUT 20 will respond with ACK data packets 27a, 27c, 27d indicating those tester data packets 17a, 17c, 17d which have been successfully received. As depicted here, the second tester data packet 17b was not correctly received by the DUT 20, thereby resulting in the absence, or non-transmission, of a corresponding ACK data packet 27b.
[0053] During this exchange of test data packets 17 and ACK data packets 27, the ACK data packets 27 are typically transmitted between sequential test data packets in response to the immediately preceding test data packet, as shown. Accordingly, in accordance with exemplary embodiments of the presently claimed invention, during this test operation in which test data packets 17 are transmitted to initiate responsive ACK data packets 27 for purposes of determining the implicit loss based on the known receiver sensitivity, the power level of the responsive ACK data packets 27 can be measured for purposes of extrapolating the output power of the signal transmitted by the DUT 20, as discussed above. (As will be readily understood, during transmission of the test data packet signal 17, the VSG 12 transmits such data packets via the antenna system 16, while during reception of the ACK data packet signal 27, the VSA 14 receives such ACK data packets 27 via the antenna system 16.)
[0054] Preferably, such measurement of the power level of the ACK data packets 27 received at the tester 10 will be performed following a predetermined time interval or reception of a predetermined number of ACK data packets 27 from the DUT to ensure that the power levels of the data packet signals transmitted by the DUT 20 have settled to their nominal power level. (Techniques for ensuring such power settling has occurred can be found in U.S. Patent Application No. 14/082,378, entitled "System and Method for Data Packet Transceiver Testing After Signal Calibration and Power Settling to Minimize Test and Time", incorporated herein by reference.) Similarly, counting of the ACK data packets 27 received at the tester 10 for purposes of measuring PER will preferably be done following such power settling as well as following reception of a sufficient number of such responsive data packets to ensure that PER is being reliably measured.
[0055] Alternatively, a technique often referred to as "confidence level testing" can be used where statistical analysis is applied to PER measurements so that pass/fail test results can be found more quickly. During such testing, the PER measurement monitors the number of packets measured and number of packet errors, and then performs a statistical analysis of the probability that the PER will or will not be exceeded. Such a statistical analysis can account for other signal conditions, parameters or characteristics, such as the presence of noise.
[0056] For example, at a confidence level 95% the PER measurement result will be deemed a "pass" before the maximum packet count is reached if there is a 95% probability that the packet errors will not exceed the PER requirement value even if the measurement continues for the maximum packet count. Conversely, the PER measurement result will be deemed a "fail" prior to reaching the maximum packet count there is a 95% probability that the packet errors counted will exceed the PER requirement if the measurement continues for the maximum packet count. In the event that the number of packet errors counted does not enable reliable prediction of a "pass" or "fail," the measurement continues for the maximum packet count. Similarly, if "confidence level testing" is not used, PER measurement runs until the specified maximum number of packets have been transmitted.Referring to Figure 4, operation of a correctly performing DUT can be confirmed as discussed above. For example, the tester transmits a tester signal 17 having a power output of -50 dBm, and the DUT 20 is known (from prior pre-assembly testing) to have a receiver sensitivity of -90 dBm. In other words, as per the examples above, the signal power received at the antenna assembly 26 of the DUT 20 will be -90 dBm for a 50% PER condition. Accordingly, the implicit loss is the difference between the tester output power (-50 dBm) and the receiver sensitivity (-90 dBm). Hence, with the DUT 20 experiencing a 50% PER during reception of a test data packet signal 17 transmitted at a power level of -50 dBM, the implicit loss is 40 dB. (As will be readily appreciated by one of ordinary skill in the art, these numbers may vary by perhaps a few tenths of a decibel (dB) due to an expected, though small, signal loss due to the DUT antenna system 26.)
[0057] Meanwhile, for purposes of testing the DUT transmitter performance, the DUT can be controlled or programmed to transmit its ACK data packets (or some other independent data packet signals) at a known power level for use in extrapolation to confirm proper performance. For example, by controlling or programming the DUT 20 to transmit its data packet signals at a power level of +15 dBm, the received DUT data packet signal at the tester 10 can be measured to confirm its power level is such that when it is added to the implicit loss the sum indicates the same power level. For example, if the tester measures its received DUT data packet signal as -25 dBm, adding the implicit loss of 40 dB to this measured power level should produce the predetermined DUT transmitter output power level of +15 dBm.
[0058] Referring to Figure 5, a defect, or reduction, in DUT receiver sensitivity can be detected as follows. As before, the tester 10 is controlled or programmed to provide an output power signal at a power level causing the DUT 20 to experience a predetermined PER condition (e.g. 50%). The difference between this tester output power level and the previously measured receiver sensitivity produces what is initially considered to be the implicit loss. For example, if a tester 10 transmitter output power of -45 dBm produces a 50% PER condition in the DUT 20, and the previously measured sensitivity was -90 dBm, then the presumed implicit loss is 45 dB. Then, this presumed implicit loss is used during transmit testing of the DUT 20 during which, at a predetermined DUT transmit power level, the tester 10 measures a received signal of -25 dBm. When this measured received signal power of -25 dBm is summed with the presumed insertion loss, the result is +20 dBm. However, the controlled or programmed output power of the DUT 20 is +15 dBm. This 5 dB difference is, therefore, likely indicative of a defect or DUT assembly issue negatively affecting the sensitivity of the DUT receiver.
[0059] Alternatively, if the DUT receiver sensitivity is assumed or otherwise known to be good, then this 5 dB difference can be indicative of an issue with the DUT transmitter output causing the output power to be higher than expected or intended.
[0060] Referring to Figure 6, a defect or assembly-related issue affecting DUT signal transmission can be detected. As before, the tester 10 is controlled or programmed to produce an output power signal level resulting in the DUT 20 experiencing a 50% PER condition. From this known tester output power level the previously measured receiver sensitivity is subtracted to produce the presumed implicit loss. For example, when such tester output power level is -50 dBm and the receiver sensitivity is -90 dBm, the presumed implicit loss is 40 dB. Then, as before, the DUT 20 is controlled or programmed to produce a transmitted signal 27 having a prescribed power level. The measured power level of the signal received by the tester 10 is added to the presumed implicit loss to extrapolate what this DUT transmit power is. For example, with a received signal power at the tester 10 of -30 dBm and a presumed implicit loss of 40 dB, the extrapolated DUT transmitter power is +10 dBm. If this matches that which was originally controlled or programmed for transmission by the DUT 20 then the transmitted power test is successful. However, if these power levels do not match, then such mismatch can be indicative of a defect or assembly-related issue affecting the DUT transmitted output power.
[0061] Referring to Figure 7, a possible defect or issue with the integrity of the antenna system of the DUT 20 can be detected as follows. As before, the tester 10 transmits signals to the DUT 20 resulting in a 50% PER condition, and the implicit loss is determined. Then, signals 27 transmitted from the DUT 20 are received and measured at the tester 10. This measured signal power at the tester 10 is summed with the presumed implicit loss to produce the extrapolated output power from the DUT 20. In this example, all data appear to be consistent with proper operation of the DUT receiver and transmitter circuits. However, when compared to the data found during testing in accordance with Figure 4, it can be seen that there is a 10 dB difference between both the receive and transmit data. Since these data are the same, i.e., for both receive and transmit tests, it appears likely that a system element common to both receive and transmit signals is defective in some way. The most likely culprit here would be something in or otherwise associated with the antenna system 26.
[0062] However, this data, by itself, is insufficient to conclude with certainty that the antenna system 26 is faulty, due to the symmetry of the implicit loss. However, by repeating these tests over multiple frequencies, variations or trends in the measured data can be analyzed for purposes of drawing more inferences about the potential cause. For example, there may be a frequency at which the antenna connection 26b has a poor impedance match with respect to the DUT 20 or antenna element 26a. Alternatively, a frequency may be found where actual signal loss becomes well defined (e.g., with little sensitivity to DUT 20 placement within the testing environment). Such inferences, in combination with subsequent absolute power measurements, may then be used to determine the actual problem.
[0063] Accordingly, as discussed above, the presently claimed invention allows implicit loss, a relative signal metric, to provide a qualitative measure of radiative signal losses in a radiative testing environment. Use of such metric along with appropriate tester output power and input power measurements enables simplified testing to determine whether a fully assembled DUT suffers from a receiver, transmitter or antenna integrity related defect.
[0064] Various other modifications and alterations in the structure and method of operation of this invention will be apparent to those skilled in the art without departing from the scope and the spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is intended that the following claims define the scope of the present invention and that structures and methods within the scope of these claims and their equivalents be covered thereby.

中文:
[0001]本发明涉及测试射频(RF)数据包信号收发器,并且更具体地涉及经由无线信号路径来测试此类装置。
[0002]许多现今的电子装置使用无线信号技术以用于连接目的和通信目的两者。因为无线装置发射并接收电磁能量,并且因为两个或更多个无线装置可能因其信号频率以及功率频谱密度而有干扰彼此的操作的可能,因此这些装置及其无线信号技术必须遵从各种无线信号技术标准规格。
[0003]在设计此类无线装置时,工程师会格外留意以确保此类装置将符合或超过其所包括的无线信号技术所规定的基于标准的规格中的每个规格。此外,当这些装置稍后进入量产时,其经过测试以确保制造缺陷不会导致不适当的操作,其也包括其对所包括的无线信号技术的基于标准的规格的遵从性。
[0004]为了在这些装置的制造以及组装之后接着对其进行测试,当前的无线装置测试系统典型地采用用于将测试信号提供至每个受测装置(DUT)并且分析从每个DUT接收的信号的测试子系统。一些子系统(通常被称为“测试器”)包括用于提供要发射至该DUT的源信号的至少一个向量信号生成器(VSG),以及用于分析由该DUT所产生的信号的向量信号分析器(VSA)。由该VSG产生测试信号并且由该VSA所执行的信号分析通常为可编程(例如,可通过使用内部可编程控制器或外部可编程控制器诸如个人计算机),以便允许每一者用于以不同的频率范围、带宽、以及信号调变特性来测试各种装置对于各种无线信号技术标准的遵从性。
[0005]在制造期间,测试此类无线装置(即,在包括系统外壳或壳体以及天线系统(取决于无线操作的模式,该天线系统可涉及一个或多个天线)的完全组装之前)通常涉及经由传导信号路径(诸如RF缆线以及连接器(例如,同轴))来在测试器与DUT之间传送测试信号。之后,在完全组装之后,通常执行进一步的测试,以确认天线系统以及连接(信号以及功率)正在正常地操作并且并未发生其他组装后的缺陷(例如,电子的、机械的、或电机的)。
[0006]可通过DUT接收器以及发射器测试的组合来确定经完全组装的DUT的正常操作,其中接收器灵敏度(例如,在误码率(BER)或误包率(PER)方面进行的测量分别被定义为不正确接收的数据位或包的数量除以所发射的位或包的总数量)比指定值更好(即,较低),并且发现发射器功率输出在期望的功率范围内。然而,由于由与测试器与DUT天线之间的距离相关联的变量(诸如信号衰减以及多路径效应)所引起的测试环境内的DUT的定位的灵敏度,因此准确确定无线测试环境(涉及对测试器和DUT之间的测试信号的传送的测试环境)中的接收器灵敏度和/或发射器输出功率往往会有问题。
[0007]为了避免这些测试问题,当可使用传导信号路径时,无法使用此类测试技术以包括来自与天线系统以及连接相关联的无线信号问题的效应。
[0009]根据所主张的本发明,提供一种用于经由无线信号媒介来测试射频(RF)数据包信号收发器受测装置(DUT)的方法,其实现经完全组装的DUT的最终功能测试,而不需要有线信号连接。可使用在该DUT与测试器之间进行无线通信的空中(OTA)测试信号来执行用于指示制造组装缺陷(诸如有缺陷的天线或子系统连接)的系统性能特性。通过使用在早期制造测试期间所确定的实际DUT性能特性(诸如接收器灵敏度以及发射器功率)以及可得自测试器发射器的已知功率水平,可估计并且使用OTA信号路径损失(即,无线信号的衰减),以确认系统操作的最终状态。
[0010]根据所主张的本发明的实施方案,一种用于经由无线信号路径来测试射频(RF)数据包信号收发器受测装置(DUT)的方法包括:
[0011]从测试器经由无线信号路径来发射测试器数据包信号,该测试器数据包信号包括多个测试器数据包并且具有如从该测试器发射的所发射的测试器数据包信号功率;
[0012]利用该测试器经由该无线信号路径来从DUT接收DUT数据包信号,该DUT数据包信号包括多个DUT数据包并且具有如在该测试器处接收的所接收的DUT数据包信号功率;
[0013]重复该测试器数据包信号以及DUT数据包信号的发射与接收,同时将该所发射的测试器数据包信号功率改变至另一所发射的测试器数据包信号功率,在该另一所发射的测试器数据包信号功率下,该多个DUT数据包以及该多个测试器数据包的比率基本上等于与该DUT的接收器灵敏度功率相关的预先确定的比率值;
[0014]计算与该另一所发射的测试器数据包信号功率与该接收器灵敏度功率之间的差值相关的无线信号路径的无线信号路径损失;以及
[0015]在利用该测试器来接收该DUT数据包信号之后,对该所接收的DUT数据包信号功率和该无线信号路径损失的至少一个总和与预期所发射的DUT数据包信号功率进行比较。
[0016]根据所主张的本发明的另一实施方案,一种用于经由无线信号路径来测试射频(RF)数据包信号收发器受测装置(DUT)的方法包括:
[0017]利用DUT从测试器经由无线信号路径来接收测试器数据包信号,该测试器数据包信号包括多个测试器数据包并且具有如从该测试器发射的所发射的测试器数据包信号功率;
[0018]利用该DUT经由该无线信号路径来发射DUT数据包信号,该DUT数据包信号包括多个DUT数据包并且具有如在该测试器处接收的所接收的DUT数据包信号功率;
[0019]利用具有另一所发射的测试器数据包信号功率的该所接收的测试器数据包信号来重复该测试器数据包信号以及DUT数据包信号的该接收与发射,在该另一所发射的测试器数据包信号功率下,该多个DUT数据包以及该多个测试器数据包的比率基本上等于与该DUT的接收器灵敏度功率相关的预先确定的比率值;
[0020]计算与该另一所发射的测试器数据包信号功率和该接收器灵敏度功率之间的差值相关的该无线信号路径的无线信号路径损失;以及
[0021]在利用该DUT发射该DUT数据包信号之后,对该所接收的DUT数据包信号功率和该无线信号路径损失的至少一个总和与预期所发射的DUT数据包信号功率进行比较。
[0022]根据所主张的本发明的另一实施方案,一种用于经由无线信号路径来测试射频(RF)数据包信号收发器受测装置(DUT)的方法包括:
[0023]从测试器经由无线信号路径来发射测试器数据包信号,该测试器数据包信号包括多个测试器数据包并且具有如从该测试器发射的所发射的测试器数据包信号功率;
[0024]利用该DUT经由该无线信号路径来接收该测试器数据包信号;
[0025]利用该DUT经由该无线信号路径来发射DUT数据包信号,该DUT数据包信号包括多个DUT数据包;
[0026]利用该测试器经由该无线信号路径来接收具有如在该测试器处接收的所接收的DUT数据包信号功率的DUT数据包信号;
[0027]重复该测试器数据包信号以及DUT数据包信号的发射与接收,同时将该所发射的测试器数据包信号功率改变至另一所发射的测试器数据包信号功率,在该另一所发射的测试器数据包信号功率下,该多个DUT数据包以及该多个测试器数据包的比率基本上等于与该DUT的接收器灵敏度功率相关的预先确定的比率值;
[0028]计算与该另一所发射的测试器数据包信号功率与该接收器灵敏度功率之间的差值相关的无线信号路径的无线信号路径损失;以及
[0029]在利用该测试器来接收该DUT数据包信号之后,对该所接收的DUT数据包信号功率和该无线信号路径损失的至少一个总和与预期所发射的DUT数据包信号功率进行比较。
[0030]图1描绘了就错误率百分比相对于所接收的信号功率(例如,BER或PER)方面而言的DUT的示例性性能曲线。
[0031]图2描绘了可确定测试器与DUT之间的无线信号路径的内隐损失(implicit loss)的无线信号测试环境。
[0032]图3描绘了在测试器与DUT之间交换的数据包信号。
[0033]图4描绘了对其中测试揭示出令人满意的接收器灵敏度以及发射器输出功率的此类无线测试环境的使用。
[0034]图5描绘了对其中测试揭示出接收器灵敏度的缺陷的此类无线测试环境的使用。
[0035]图6描绘了对其中测试揭示出发射器输出功率的缺陷的此类无线测试环境的使用。
[0036]图7描绘了对其中测试揭示出天线系统的完整性的缺陷的此类无线测试环境的使用。
[0037]以下详细描述是参照附图的所主张的本发明的示例性实施方案。此类描述相对于本发明的范围旨在是示例性的而非限制性的。此类实施方案足够详细地被描述,以使得本领域中的一个普通技术人员能够实施本发明,并且应当理解,在不脱离本发明的实质或范围的情况下,可利用一些改变来实施其他实施方案。
[0038]在整个本公开中,在缺少与上下文相反的明确指示的情况下,将理解所描述的各个电路元件在数量上可为单个或多个。例如,术语“电路”以及“电路系统”可包括单个或多个组件,可为主动的和/或被动的,并且经连接或以其他方式耦接在一起(例如,作为一个或多个集成电路芯片),以提供所述功能。另外,术语“信号”可指一个或多个电流、一个或多个电压、或数据信号。在附图内,类似或相关的元件将具有类似或相关的字母、数字、或字母数字标志符号。此外,尽管本发明已在使用离散电子电路系统(优选的是以一个或多个集成电路芯片的形式)的具体实施的上下文中被讨论,但取决于待处理的信号频率或数据速率,仍可替代地使用一个或多个经适当编程的处理器来实施此类电路系统的任何部分的功能。此外,就附图示出各种实施方案的功能块的图示来说,该功能块不一定指示硬件电路系统之间的划分。
[0039]无线装置诸如手机、智能手机、平板电脑等使用基于标准的技术(例如IEEE802.11a/b/g/n/ac、3GPP LTE、以及蓝芽)。构成这些技术的基础的标准被设计为提供可靠的无线连接性和/或通信。该标准规定通常被设计为高能源效率并使得使用相同或其他技术的邻近或分享无线频谱的装置之间的干扰最小化的物理规格以及更高级别的规格。
[0040]由这些标准所规定的测试意指要确保此类装置被设计以符合标准规定的规格,并确保所制造的装置持续符合这些所规定的规格。大多数装置为包括至少一个或多个接收器以及发射器的收发器。因此,该测试旨在确认接收器以及发射器两者是否均符合规格。DUT的一个或多个接收器的测试(RX测试)通常涉及测试系统(测试器)将测试包发送至该一个或多个接收器以及确定该一个或多个DUT接收器如何对那些测试包进行响应的某种方式。DUT的发射器通过使其将包发送至测试系统而被测试,该测试系统然后评估由DUT所发送的信号的物理特性。
[0041]根据所主张的本发明的示例性实施方案,如下文所更详细讨论的,有可能确定是否已发生影响DUT的接收器灵敏度或发射器功率性能的制造和/或组装缺陷,而无需首先确定无线测试环境中的绝对信号路径损失。如本领域中的普通技术人员将易于理解的,使用传导性信路径来测试经部分组装的DUT将具有确保的令人满意的接收器信号灵敏度。此类所测量的灵敏度不应作为DUT的完全组装的结果而受到影响或以其他方式改变,并且应用作参考点以供以后使用。这应大致上保持成立,因为最终的组装不应影响DUT的任何主动电路系统,并且仅被动装置通常存在于此类主动电路系统的外部。
[0042]然后,在完全组装DUT之后,可通过提供具有经减小至在制造测试期间所确定的产生已知的或规定的错误率(例如,50%PER)的功率水平的测试器信号来测试接收器灵敏度。此外,如下文所更详细讨论的,这还使得能够在基于测试DUT的灵敏度期间由DUT所发射的响应数据包(例如,确认(ACK)数据包)来测量DUT发射功率。
[0043]参见图1,50%PER点优选地被用作DUT的典型PER曲线(DUT在此点处具有其最大斜率),从而使DUT对统计上的变化较不敏感。此外,这实现较容易的迭代算法,从而实现较快速的测试。(参见例如标题为“Method for Testing Sensitivity of a Data PacketSignal Transceiver”的美国专利申请号13/959354,该专利申请以引用方式并入本文)。当然,也可使用除50%之外的PER点,以用于确定所测量的PER点是否较小或较大,以及用于限定DUT接收器灵敏度(即,由接收器检测以确保未超过指定的最大接收PER的最小信号水平)。
[0044]如下文所更详细讨论的,由测试器所发射的信号的辐射功率水平与先前所测量的DUT接收器灵敏度功率水平(该参考点)之间的差值解释无线信号测试环境内的内隐损失(包括信号路径损失)。如所提及的,对于从DUT传送至测试器的信号,该内隐损失在实质上也将是相同的,前提是无线测试环境内的DUT相对于测试器的定位保持恒定,并且测试器发射信号以及DUT发射信号以相同的频率或在相对窄的频率范围内被发射。(如将易于理解的是,在其范围内可预期结果为合理一致的任何可能的频率范围将取决于相应频率分量的信号相位受到无线信号环境影响的程度)。
[0045]因此,一旦已确定该内隐损失图,可针对DUT接收器测试信号来与所预期的接收器灵敏度图一起使用该内隐损失图,并且针对DUT发射器信号来与所预期DUT输出功率信号水平一起使用该内隐损失图,以用于确认接收器以及发射器信号性能以及路径完整性。如下文所更详细讨论的,通过确定这些图与所预期的那些的图如何不同,在失效是由于DUT的接收或发射信号路径中的制造或组装相关的缺陷(例如,DUT接收器灵敏度减小或天线系统或连接的问题)导致的情况下,其可被确定。
[0046]参见图2,根据所主张的本发明的示例性实施方案的用于执行测试的无线信号测试环境包括由无线信号路径30分离的测试器10以及DUT 20。(如将易于理解的是,该测试环境可按需要扩展以包括多个DUT,以用于同时或连续测试多个DUT)。测试器10通常包括(或可远程访问和控制)测试信号来源(例如,一VSG 12)以及测试信号分析系统(例如,VSA14),如前文所提及的。该测试器10还包括天线系统16,该天线系统16包括天线16a(其替代地可包括多个天线元件)以及天线连接件16b(例如,如在本领域中所熟知并且使用的螺纹同轴RF信号连接器),天线连接件16b用于将天线16a电连接(并且通常机械地固定)至测试器10以及测试器10内的电路系统。由天线系统16辐射来自信号来源12的测试信号,以用作由DUT 20接收的无线信号17。
[0047]类似地,DUT 20包括具有一个或多个天线元件26a及天线连接件26b的天线系统26。该天线系统26辐射来自DUT 20的无线DUT信号27以用于由测试器10接收。
[0048]虽然此处未显示,但还包括控制器诸如个人计算机,该控制器包含并执行测试程序以用于以使得内部信号源12提供适当的测试信号以供DUT 20接收的方式来控制测试器10,并且控制内部信号分析系统14以用于接收并且分析从DUT 20接收的信号。
[0049]替代地,测试器10和/或DUT 20可利用测试命令以及响应进行预程序化,以用于响应于测试器10与DUT 20之间的经由无线信号路径30交换的无线信号来执行测试,其中无或有少许外部控制。此类测试技术描述于美国专利申请号7,689,213及美国专利申请号8,811,194中,该专利申请以引用方式并入本文。
[0050]在测试期间,测试器将具有被提供至天线系统16的具有等于预先确定的或程序化功率水平P2的已知功率水平P输出的信号输出功率。DUT 20将具有在制造测试期间所确定的已知接收器灵敏度P50(例如,DUT的误包率为50%的所接收的信号功率水平,如上文所讨论的)。内隐损失主要为测试器与DUT之间的无线信号路径30的信号路径损失,并且可通过发现测试器功率水平P2与接收器灵敏度水平P50之间的差值P2-P50来进行计算。(如将易于理解的是,虽然此计算不精确,但是其为良好的估计。即使精确的灵敏度值未知(例如,仅测量PER),但仍已知灵敏度将在被定义为在PER测试点与由DUT接收器的固有噪声图所建立的较低界限之间的窄范围内)。
[0051]因为信号路径损失对称(如上文所讨论的),所以从DUT 20发射至测试器10的信号27将还经受此内隐损失。可使用如在测试器10接收的DUT信号27的功率水平(例如,如通过VSA 14所测量的),以通过添加该内隐损失P输出=P输入+IL来外推由DUT 20所发射的信号27的输出功率水平。(这可通过针对每次测量来控制或程序化DUT 20以根据多个预先确定的功率水平来发射其信号27并且外推输出功率水平来进行确认)。
[0052]参见图3,根据熟知的系统以及原理,通过从测试器发射数据包信号17(DUT通过发送响应数据包27(例如,ACK数据包)来对数据包信号17进行响应)来测试无线数据包收发器系统。因此,测试器10将发射一序列的测试数据包17a、17b、17c、17d,该DUT 20将利用用于指示已成功接收测试器数据包17a、17c、17d的这些ACK数据包27a、27c、27d来对这些测试数据包进行响应。如此处所描绘的,DUT 20未正确接收第二测试器数据包17b,从而导致对应的ACK数据包27b不存在或未发射。
[0053]在测试数据包17以及ACK数据包27的交换期间,响应于紧邻此前的测试数据包而通常在循序测试数据包之间发射ACK数据包27,如所显示的。因此,根据所主张的本发明的示例性实施方案,在为了基于已知的接收器灵敏度看来确定内隐损失而发射测试数据包17以发起响应性ACK数据包27的该测试操作期间,可为了外推由DUT 20发射的信号的输出功率来测量响应性ACK数据包27的功率水平,如上文所讨论的。(如将易于明白的,在发射测试数据包信号17期间,该VSG 12经由天线系统16来发射此类数据包,同时在接收ACK数据包信号27期间,该VSA 14经由天线系统1 6来接收此类ACK数据包27)。
[0054]优选地,可在预先确定的时间间隔之后或在从DUT接收到预先确定的的数量ACK数据包27之后,执行在测试器10处所接收的ACK数据包27的功率水平的此类测量,以确保由DUT 20发射的数据包信号的功率水平保持在其标称功率水平。(用于确保此类功率保持已发生的的技术可在标题为“System and Method for Data Packet Transceiver TestingAfter Signal Calibration and Power Settling to Minimize Test and Time”的美国专利申请号14/082,378中发现),该专利申请以引用方式并入本文。同样,优选地,在此类功率保持之后以及在接收到足够数量的此类响应数据包之后,进行在测试器10处接收的ACK数据包27的计数以用于测量PER,从而确保可靠地测量PER。
[0055]替代地,可使用通常被称为“置信度水平测试”的技术,其中将统计性分析应用至PER测量,使得可更迅速发现合格/不合格的测试结果。在此类测试期间,PER测量监测所测量的包的数量以及误包的数量,并且然后执行对将超过或将不超过PER的可能性的统计性分析。此类统计性分析可考虑其他信号条件、参数、或特性,诸如噪声的存在。
[0056]例如,在95%的置信度水平下,在到达最大包计数之前,即使持续测量对最大包计数,误包仍有95%的可能性将不超过PER要求值,则PER测量结果仍将视为“合格的”。相反的,在达到最大包计数之前,如果持续测量最大包计数,被计数的误包有95%的可能性超过PER要求,则PER测量结果将视为“不合格的”。在被计数的误包的数量未实现可靠的预测“合格”或“不合格”的情况下,则持续测量最大包计数。类似地,如果不使用“置信度水平测试”,则PER测量运行,直到已发射包的指定的最大数量。参见图4,可如上文所讨论来确认正确执行DUT的操作。例如,测试器发射具有-50dBm的功率输出的测试器信号17,并且(从先前预组装测试)已知DUT 20具有-90dBm的接收器灵敏度。换句话讲,按照上述示例,针对50%的PER条件,在DUT 20的天线组件26处接收的信号功率将为-90dBm。因此,内隐损失为测试器输出功率(-50dBm)与接收器灵敏度(-90dBm)之间的差值。因此,在接收以-50dBM功率水平发射的测试数据包信号17期间DUT 20经受50%PER的情况下,内隐损失为40dB。(如本领域中的普通技术人员将易于理解的,由于DUT天线系统26而导致预期(虽然小)信号损失,这些数量有可能变化几十分贝(dB))。
[0057]同时,为了测试DUT发射器性能,可控制DUT或对其程序化,从而以已知的功率水平来发射其ACK数据包(或一些其他独立的数据包信号),以在外推中使用从而确认正常性能。例如,通过控制DUT或对其程序化从而以+15dBm功率水平来发射其数据包信号,可测量测试器10处的所接收的DUT数据包信号以确认其功率水平,使得当被添加至内隐损失时,总和指示相同的功率水平。例如,如果测试器测量其所接收的DUT数据包信号为-25dBm,则将40dB的内隐损失添加至该所测量的功率水平应产生+15dBm的预先确定的DUT发射器输出功率水平。
[0058]参见图5,可如下检测DUT接收器灵敏度的缺陷或减小。如前所述,控制测试器10或对其程序化从而以引起DUT 20经受预先确定的PER条件(例如50%)的功率水平来提供输出功率信号。该测试器输出功率水平与先前所测量的接收器灵敏度之间的差值产生最初视为内隐损失的内容。例如,如果测试器10的-45dBm的发射器输出功率在DUT 20中产生50%PER条件并且先前所测量的灵敏度为-90dBm,则推测内隐损失为45dB。然后,在DUT 20的发射测试期间使用该所推测的内隐损失,在此期间测试器10以预先确定的DUT发射功率水平来测量-25dBm的所接收的信号。当-25dBm的该所测量的所接收的信号功率与所推测的插入损失相加时,结果为+20dBm。然而,DUT 20的受控制或经程序化的输出功率为+15dBm。该5dB差值很可能因此指示负面影响DUT接收器的灵敏度的缺陷或DUT组装问题。
[0059]替代地,如果DUT接收器灵敏度经假设或以其他方式已知为良好的,则该5dB差值可指示引起输出功率高于预期或意指的功率的DUT发射器输出的问题。
[0060]参见图6,可检测影响DUT信号发射的缺陷或组装相关的问题。如前所述,控制测试器10或对其程序化从而以引起DUT 20经受50%PER条件的功率水平来产生输出功率信号。自此已知的测试器输出功率水平减去先前所测量的接收器灵敏度以产生经推测的内隐损失。例如,当此类测试器输出功率水平为-50dBm并且接收器灵敏度为-90dBm时,所推测的内隐损失为40dB。然后,如前所述,DUT 20被控制或程序化以产生具有规定功率水平的发射信号27。由测试器10接收的信号的所测量的功率水平被添加至所推测的内隐损失,以外推DUT发射功率。例如,利用测试器10处的-30dBm的所接收的信号功率以及40dB的推测内隐损失,外推DUT发射器功率为+10dBm。如果该匹配初始经控制或经程序化以用于由DUT 20发射,则发射功率测试成功。然而,如果这些功率水平不匹配,则此类不匹配可指示影响DUT所发射的输出功率的缺陷或组装相关的问题。
[0061]参见图7,可如下检测DUT 20的天线系统的完整性的可能缺陷或问题。如前述,测试器10将信号发射至DUT 20,从而导致50%PER条件,并且确定内隐损失。然后,在测试器10处接收并且测量从DUT20发射的信号27。测试器10处的该所测量的信号功率与所推测的内隐损失相加,以产生来自DUT 20的经外推的输出功率。在该示例中,所有数据似乎与DUT接收器以及发射器电路的正常操作一致。然而,当与根据图4在测试期间发现的数据进行比较时,可看到在接收数据以及发射数据两者之间皆存在10dB的差值。由于这些数据相同,即对于接收测试以及发射测试两者,接收信号以及发射信号共有的系统元件似乎有可能在某些方面有缺陷。此处最有可能造成缺陷的一方将位于天线系统26中或以其他方式与该天线系统26相关联。
[0062]然而,由于内隐损失的对称性,该数据本身不足以确定地断定天线系统26有故障。然而,通过以多个频率重复这些测试,可分析所测量的数据的变化或趋势,以用于绘制关于潜在原因的更多推论。例如,可存在天线连接件26b具有相对于DUT 20或天线组件26a的不良阻抗匹配的频率。替代地,可发现其中实际信号损失变成被完全定义的频率(例如,测试环境内的DUT 20放置灵敏度的很小)。可然后使用此类推论与随后绝对功率测量的组合来确定实际问题。
[0063]因此,如上文所讨论的,所主张的本发明允许内隐损失(相对信号测量),以提供辐射测试环境中的辐射信号损失的定量测量。使用此类测量连同适当的测试器输出功率以及输入功率测量来实现简化测试,以确定经完全组装的DUT是否遭受到接收器、发射器或天线完整性相关缺陷的困扰。
[0064]本发明的结构和操作方法的各种其他修改以及替代形式在不背离本发明的实质与范围的情况下,对于本领域中的普通技术人员而言将是显而易见的。尽管已结合特定优选实施方案描述了本发明,但是应当理解,所主张的本发明不应过度地受限于这些特定实施方案。其旨在以下列权利要求书限定本发明的范围并且在这些权利要求书的范围内的结构与方法以及其等同形式被涵盖。