PATENT DOCUMENT

Publication Number: US-9190725-B2
Application Number: US-201313787515-A
Country: US
Kind Code: B2

Title: Test system having test stations with adjustable antennas

Abstract:
A test system may include a master test station and slave test stations. The test stations may receive devices under test such as portable wireless electronic devices. Each test station may have adjustable antenna structures coupled to test equipment. The adjustable antenna structures may include antenna support structures on which test antennas are mounted and rail along which the antenna support structures and test antennas are moved by a pneumatic positioner. A rotatable platform may be provided in each test station to support the device under test in that test station. By making a series of over-the-air test measurements in the master test station while adjusting the antenna system and device positioning system, a satisfactory location for the active test antenna and device position may be identified. This configuration may then be used in performing single-point over-the-air tests in the slave test stations.

Claims:
What is claimed is: 
     
       1. A method of testing wireless electronic devices under test, comprising:
 in a master test station in which a device under test is located, adjusting an adjustable antenna system to identify a satisfactory position for an antenna in the adjustable antenna system for making test measurements on the device under test, wherein the adjustable antenna system comprises a plurality of antennas mounted on antenna support structures and a rail along which the antenna support structures are positioned, the rail has a slot along which the antenna support structures are positioned, and the adjustable antenna system comprises switching circuitry on the antenna support structures; 
 with the switching circuitry, switching a selected one of the plurality of antennas into use; 
 adjusting an adjustable antenna system in each of a plurality of slave test stations to place antennas in the adjustable antenna systems of the slave test stations in the satisfactory position; and 
 while the antennas in the adjustable antenna systems of the slave test stations are in the satisfactory position, wirelessly testing respective devices under test in the slave test stations using the antennas in the adjustable antenna systems of the slave test stations. 
 
     
     
       2. The method defined in  claim 1  wherein wirelessly testing the respective devices under test comprises performing single-point over-the-air measurements in which the antennas in the adjustable antenna systems of the slave test stations are in fixed positions relative to the respective devices under test. 
     
     
       3. The method defined in  claim 1  wherein the adjustable antenna system in the master test station comprises an antenna support structure, a plurality of antennas mounted to the antenna support structure, and a positioner and wherein adjusting the adjustable antenna system in the master test station comprises positioning the antenna support structure with the positioner. 
     
     
       4. The method defined in  claim 3  wherein the antenna system in the master test station comprises radio-frequency switching circuitry and wherein adjusting the adjustable antenna system in the master test station comprises switching a given one of the plurality of antennas into use with the radio-frequency switching circuitry. 
     
     
       5. The method defined in  claim 4  wherein the slave test stations each include a positioning system on which the respective device under test in that slave test station is supported, the method further comprising rotating the respective device under test in each slave test station to a position for wireless testing based on information from the master test station. 
     
     
       6. The method defined in  claim 5  wherein wirelessly testing the respective devices under test comprises performing single-point over-the-air measurements in which the antennas in the adjustable antenna systems of the slave test stations are in fixed positions relative to the respective devices under test. 
     
     
       7. A wireless test system for testing radio-frequency transceiver circuitry in devices under test, comprising:
 a master test station having test equipment and having a test chamber that contains an adjustable antenna system that is coupled to the test equipment of the master test station, wherein the test chamber receives a given one of the devices under test; 
 a plurality of slave test stations each of which has test equipment and a test chamber that contains an adjustable antenna system that is coupled to the test equipment of the slave test station, wherein each test chamber receives a respective one of the devices under test, the master test station is operable to configure the slave test stations based on test measurements made on the given one of the devices under test with the master test station and wherein each of the plurality of slave test stations is operable to test the respective one of the devices under test in the test chamber of that slave test station after being configured by the master test station based on the test measurements, and the adjustable antenna system in the master test station comprises a plurality of antennas on antenna support structures; and 
 a rail in the adjustable antenna system of the master test station with a slot along which the antenna support structures are positioned, wherein the adjustable antenna system in the master test station comprises switching circuitry on the antenna support structures that is configured to switch a selected one of the plurality of antennas into use. 
 
     
     
       8. The wireless test system defined in  claim 7  wherein the adjustable antenna system in the master test station comprises a positioner that positions the antenna support structures. 
     
     
       9. The wireless test system defined in  claim 8  wherein the antennas comprise patch antennas. 
     
     
       10. The wireless test system defined in  claim 9  further comprising pyramidal absorbers that cover at least part of the rail. 
     
     
       11. The wireless test system defined in  claim 10  wherein the adjustable antenna system in each slave test chamber has at least three antennas and wherein the adjustable antenna system in each slave test chamber has switching circuitry that is configured to switch a selected one of the three antennas into use. 
     
     
       12. The wireless test system defined in  claim 11  wherein each of the slave test stations includes a positioning system that positions the respective one of the devices under test in that slave test station. 
     
     
       13. The wireless test system defined in  claim 12  wherein the positioning system in each slave test station includes a rotatable platform and a positioner that rotates the platform, wherein the respective one of the devices under test in each slave test station is supported on the rotating platform in that slave test station. 
     
     
       14. The wireless test system defined in  claim 8  wherein the positioner comprises a pneumatic positioner that moves the antenna support structures.

Description:
BACKGROUND 
     This relates to electronic devices and, more particularly, to systems for testing wireless electronic devices. 
     Electronic devices such as cellular telephones and other portable devices are often provided with wireless circuitry. For example, cellular telephones contain wireless radio-frequency transceiver circuitry for communicating using cellular telephones bands. Electronic devices may also contain circuitry for communicating using wireless local area network communications bands and other communications bands of interest. 
     During manufacturing, wireless tests are performed on electronic devices to ensure that the devices are operating satisfactorily. For example, single-point over-the-air tests are performed with an antenna in a single fixed position within a wireless test chamber to determine whether devices exhibit desired levels of wireless receiver sensitivity or other performance characteristics under a variety of operating conditions. In a typical over-the-air test of this type, a wireless electronic device under test is placed within a test chamber to allow wireless measurements to be made. Using trial and error, the device can be manually positioned relative to a test antenna in the test chamber until the device has been oriented properly to allow the test antenna to gather sufficiently strong signals for wireless test measurements. This type of manual process can be cumbersome and prone to error. 
     It would therefore be desirable to be able to provide improved testing systems for wireless electronic devices. 
     SUMMARY 
     A test system may include a master test station and slave test stations. The test stations may receive devices under test such as portable wireless electronic devices. Wireless testing may be performed on the devices under test to determine whether the devices under test are performing satisfactorily. 
     Each test station may have adjustable antenna structures coupled to test equipment. The adjustable antenna structures may include antenna support structures on which multiple test antennas are mounted. There may be three or more test antennas such as three or more patch antennas. Each antenna may be coupled to the test equipment using switching circuitry and transmission lines. The switching circuitry may be controlled by the test equipment so that the test equipment can switch a desired antenna into use. The antenna support structures may slide within a rail. The position of the antenna support structures and the test antennas along the rail may be controlled using a pneumatic positioner. A rotatable platform may be provided in each test station to support the device under test in that test station. 
     By making a series of over-the-air test measurements in the master test station while adjusting the antenna system and device positioning system, a satisfactory location for the active test antenna and device position within the test station may be identified. This configuration may then be used in performing single-point over-the-air tests in the slave test stations. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device of the type that may be tested using a wireless test system in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative wireless test station and an associated wireless electronic device under test in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of an illustrative wireless test station having an adjustable antenna system and device positioning equipment in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram showing how a test station may be provided with an antenna system that can be adjusted using positioning and switching circuitry in accordance with an embodiment of the present invention. 
         FIG. 5  is a diagram of a test system having a master test station and multiple associated slave test stations in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional view of an illustrative cable containing multiple individual antenna cables in accordance with an embodiment of the present invention. 
         FIG. 7  is a bottom perspective view of an illustrative adjustable antenna system having multiple movable antennas that can slide along a rail in accordance with an embodiment of the present invention. 
         FIG. 8  is a top perspective view of the illustrative adjustable antenna system of  FIG. 7  in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional perspective view of a test chamber with an adjustable antenna system in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional perspective view of the test chamber of  FIG. 9  showing how structures such as a rail in an adjustable antenna system may be shielded using radio-frequency absorbers in accordance with an embodiment of the present invention. 
         FIG. 11  is a flow chart of illustrative steps involved in using a test system with adjustable antenna structures to perform wireless tests on devices under test such as single-point over-the-air tests in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Wireless testing may be performed on electronic equipment that communicates using wireless signals. The electronic equipment that is being tested may sometimes be referred to as a wireless electronic device or device under test. 
     An illustrative electronic device of the type that may be wirelessly tested is shown in  FIG. 1 . Device  10  of  FIG. 1  may be a handheld device such as a cellular telephone or media player, a tablet computer, a notebook computer, other portable computing equipment, a wearable or miniature device such as a wristwatch or pendant device, a television, a computer monitor, a computer integrated into a computer display, a set-top box, a wireless access point, a desktop computer, or other electronic equipment. 
     As shown in  FIG. 1 , electronic device  10  may include a display such as display  14 . Display  14  may be a touch screen that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components or may be a display that is not touch-sensitive. Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16  and an opening such as opening  18  may be used to form a speaker port. Device configurations without openings in display  14  may also be used for device  10 . 
     Device  10  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. 
     Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Device  10  may have one or more connector ports such as connector port  20 . Connector port  20  may have a male connector, a female connector, or may form part of a symmetrical connector. Devices under test such as device  10  of  FIG. 1  may have any suitable number of connectors  20 , may have any suitable number of contacts in each connector  20 , and may have connectors  20  of any suitable shape (e.g., audio jack format, data port format, Universal Serial Bus format, etc.). Using connector port  20  and optional wired path  26 , external equipment  22  may communicate with device  10 . External equipment  22  also communicates wirelessly with device  10 , as indicated by wireless signals  24 . External equipment  22  may include computing equipment, peer devices, test system equipment, etc. During testing operations, external equipment  22  such as test equipment may be used in performing wireless tests on device  10 . For example, external equipment  22  may be associated with a wireless test station in a test system. 
     Wireless testing may be performed in a test chamber. If desired, power can be provided to devices under test using cables and cables can be used to communicate with devices under test. For example, devices under test may be tethered to cables within a test chamber. Often, however, it may be desirable to perform tests without any attached cables. If cables are attached to a device under test during testing, the cables may electromagnetically influence radio-frequency signals in the vicinity of the device under test and lead to potentially inaccurate test results. 
     In order to wirelessly test a device under test in a wireless test chamber without any attached cables, devices under test may be powered with batteries. For example, a cellular telephone or tablet computer that is being wirelessly tested may use internal battery power to operate radio-frequency transceiver circuitry within the device under test. 
     To enhance testing efficiency, automated processes may be used to make adjustments within a test system that is being used to test the devices under test. As an example, a set of devices under test can be loaded into a series of test stations that are automatically placed in satisfactory configurations to support desired wireless tests. This allows devices under test to be tested efficiently with little or no intervention from an operator. The tests that are performed this way may be single-point over-the-air tests in which a test antenna that is located at a single fixed point within the test chamber is used to make measurements such as receiver sensitivity measurements. The receiver sensitivity measurements or other over-the-air test measurements may sometimes be made both in the presence and in the absence of potential interference from a component in device  10  such as display  14  to determine whether or not the component can be operated without degrading device performance by an unacceptable amount. 
       FIG. 2  is a diagram of illustrative test system equipment that may be used in testing device under test  10 . As shown in  FIG. 2 , test system  28  may include test stations such as test station  30  for use in testing devices under test such as device under test  10 . Test stations  30  may include adjustable test antennas, positioning equipment for positioning a device under test, and test equipment for controlling test operations and gathering test data. Test stations such as test station  30  may be coupled to device under test  10  using an optional wired path such as wired path  26  or wired path  26  may be omitted during testing to avoid interfering with wireless test measurements. Wireless signals  24  (e.g., wireless test signals) may be conveyed wirelessly between device under test  10  and test station  30  during testing. 
     Device under test  10  may include storage and processing circuitry  32 . Storage and processing circuitry  32  may include one or more processors such as microprocessors, microcontrollers, control circuits that are part of application-specific integrated circuits, audio integrated circuits, and other control circuitry. Storage and processing circuitry  32  may also include memory integrated circuits, hard disk drives, solid state drives, removable storage media, and other components for storing data. 
     Device  10  may receive power from external sources (e.g., alternating current or direct current power may be received via connector  20 ) and may use power management circuitry to provide corresponding internal power to battery  34  and the other components of device  10 . Power management circuitry in device  10  may also be used to provide power from battery  34  to external accessories that are coupled to device  10  and to internal device components. 
     Input-output circuitry  36  may include buttons, sensors, light-emitting components such as status indicator lights, audio components such as microphones and speakers, touch screen displays, displays without touch functionality, touch pads, keyboards, and other input-output components. Wired communications circuitry such as circuitry  38  may include transmitter and receiver circuitry for conveying data over wired communications paths such as optional path  26  (e.g., serial and/or parallel bus data paths coupled to connector  20 , etc.). Communications circuitry  38  may, for example, include Universal Serial Bus communications circuitry that is coupled to contacts in connector  20 . 
     Wireless circuitry  40  may include radio-frequency transceiver circuitry  42  and antenna structures  44 . Radio-frequency transceiver circuitry  42  may include cellular telephone transceiver circuitry, wireless local area network transceiver circuitry (e.g., IEEE 802.11 circuitry), and satellite navigation system receiver circuitry (e.g., a receiver for receiving Global Positioning System signals). Wireless circuitry  40  may also include near field communications circuitry, circuitry for receiving radio signals, television signals, and paging signals, and transceiver circuitry for handling other communications bands of interest. 
     Antenna structures  44  may include one or more antennas such as inverted-F antennas, planar inverted-F antennas, patch antennas, monopole antennas, dipole antennas, loop antennas, closed and open slot antennas, antennas of other designs, and hybrid antennas that are formed from one or more antenna resonating element structures such as these. There may be one antenna in device  10 , more than one antenna in device  10 , two or more antennas in device  10 , three or more antennas in device  10 , or four or more antennas in device  10 . 
     Test station  30  may include one or more test antennas. The test antennas may transmit wireless signals  24  that are received by antennas  44  of device  10  and may receive wireless signals  24  that are transmitted by antennas  44  of device  10 . The test antennas of test station  30  may be organized in an array and/or may be mounted on movable equipment (e.g., a pneumatically controlled rail system) that allows the antennas to be moved into a variety of different orientations with respect to device under test  10 . Device under test  10  may also be positioned using a computer-controlled positioner during use of system  28 . A rotatable platform such as a round turntable or other support structure may, for example, be controlled using a controller associated with test station  30 . 
       FIG. 3  is a diagram of an illustrative test station such as test station  30  of  FIG. 2 . As shown in  FIG. 3 , test station  30  may include a chamber such as chamber  46 . Chamber  46  may have metal sidewalls to prevent wireless interference from escaping from the interior of chamber  46  and to prevent wireless interference from outside of chamber  46  entering into the interior of chamber  46 . The inner surface of the walls of chamber  46  may be lined with pyramidal absorbers such as pyramidal anechoic chamber wall absorbers  48  to suppress reflections of internal signals that might otherwise have a potential to interfere with the wireless measurements being made. 
     Device under test  10  may be supported by computer-controlled positioning structures such as positioning system  50 . In the example of  FIG. 3 , positioning system  50  includes rotatable disk-shaped platform  62 . Platform  62  is mounted on rotating shaft  52 . Positioner  56  may rotate shaft  52  in directions  54  using positioner  56  in response to control signals received from test equipment  60  over path  58 . If desired, positioner  56  may be used to translate device under test  10  or perform other positioning operations. 
     Test station  30  may include adjustable antenna system  64 . Adjustable antenna system  64  may include one or more antennas such as test antennas  66 . Test antennas  66  may be used in transmitting wireless radio-frequency signals  24  to device under test  10  for reception by a receiver in radio-frequency transceiver circuitry  42 . Test antennas  66  may also be used in receiving wireless radio-frequency signals  24  that have been transmitted by transceiver circuitry  42  to test equipment  60 . Test circuitry within test equipment  60  such as vector network analyzer equipment, power meter equipment, call box equipment, and other test equipment may be used in performing wireless tests with device under test  10  (e.g., signal strength tests, etc.). Test equipment  60  and antennas such as antenna  66  may be coupled to each other using coaxial cables or other transmission line structures  72 . 
     Adjustable antenna system  64  may include positioner equipment and switching circuitry  68  containing one or more positioners for positioning antennas  66  relative to device under test  10  and containing radio-frequency switching circuitry for routing radio-frequency signals to and from a selected antenna within an array of multiple antennas  66 . Positioner and switching circuitry  68  may include a positioner such as pneumatic positioning equipment, motor-driven positioning equipment, solenoid-based actuators, or other equipment for adjusting the position of antennas  66  relative to device under test  10  in response to control signals from test equipment  60  received using path  70 . Positioner and switching circuitry  68  may also include switches or other adjustable switching circuitry that can be configured to switch a selected one of antennas  66  into use (e.g., by coupling that antenna to an appropriate transmission line path in path  72 ). 
       FIG. 4  is a diagram of illustrative adjustable antenna system  64  and test equipment  60  in a configuration in which adjustable antenna system  64  has three test antennas  66  (i.e., test antenna  66 A,  66 B, and  66 C). Test equipment  60  may include radio-frequency transceiver circuitry for generating and receiving radio-frequency test signals. Transmission line path  72  may be used in conveying radio-frequency signals between transceiver  78  and antennas  66 . 
     Switching circuitry  68 B may be configured in response to control signals received from test equipment controller  76  via control path  70 B. If, for example, test equipment  60  desires to switch antenna  66 A into use, the uppermost switch  68 B in  FIG. 4  may be turned on while remaining switches  68 B may be turned off. This switches antenna  66 A into use and switches antennas  66 B and  66 C out of use. 
     Controller  76  can also issue control commands to positioner  68 A using control path  70 A. Positioner  68 A may include a pneumatically controlled actuator or other positioner for adjusting the position of antennas  66  within chamber  46  relative to device under test  10 . The positioner may be, for example, a pneumatic positioner that slides antennas  66  along a rail or other linear positioning structure. 
     There may be more than one test station  30  in test system  28 . As shown in  FIG. 5 , for example, test stations  30  may include a master test station such as master test station  30 M and multiple associated slave test stations such as slave test stations  30 S. Each test station may be loaded with a corresponding device under test  10 . An adjustable antenna system  64  and adjustable device positioning system  50  in each test station may be controlled by associated test equipment  60  to ensure that wireless tests can be performed satisfactorily. 
     With one illustrative arrangement, master test station  30 M can make a series of adjustments to the position of antennas  66 , the selection of which antenna  66  is being switched into use, and the position of device  10  within chamber  46  until a satisfactory configuration for use in single-point over-the-air wireless tests with a fixed-position antenna and fixed-position device under test has been identified. In this satisfactory configuration, signal strengths are sufficiently high to make accurate measurements of parameters such as receiver sensitivity, etc. After identifying the satisfactory configuration for making wireless over-the-air test measurements, test equipment  60  may configure each antenna system  64  and positioning system  50  in slave test stations  30 S in the same way, so that devices under test  10  in the slave test stations can be tested using the same satisfactory configuration. Test equipment  60  may include test equipment at master test station  30 M, test equipment at slave test stations  30 M, and other test equipment. Test equipment  60  may be interconnected using wired and wireless communications paths such as paths  80 . Computing equipment (e.g., one or more computers, embedded processors, application-specific integrated circuits, test units, or other equipment) may be used in test equipment  60  to perform functions such as data acquisition, control of antennas and positioners, data analysis, control of slave test stations, etc. 
       FIG. 6  is a cross-sectional side view of transmission line cable  72  in a configuration in which multiple coaxial cables  72 ′ have been routed within the interior of a larger cable structure  72 SH. This type of cabling may be used to couple three respective antennas  66  such as antennas  66 A,  66 B, and  66 C to test equipment  60 . A first one of cables  72 ′ in cable  72  may be coupled between test equipment  60  and a first of switches  68 B in adjustable antenna system  64  of  FIG. 4 , a second one of cables  72 ′ in cable  72  may be coupled between test equipment  60  and a second of switches  68 B in adjustable antenna system  64  of  FIG. 4 , and a third one of cables  72 ′ in cable  72  may be coupled between test equipment  60  and a third of switches  68 B in adjustable antenna system  64  of  FIG. 4 . Cables such as cable  72  of  FIG. 6  may be provided with other numbers of coaxial cables or with transmission lines of other types. The configuration of  FIG. 6  is merely illustrative. 
       FIG. 7  is a bottom perspective view of an illustrative adjustable antenna system. As shown in  FIG. 7 , adjustable antenna system  64  of  FIG. 7  has three patch antennas  66 A,  66 B, and  66 C. In general, test antennas  66  may be inverted-F antennas, loop antennas, monopole antennas, dipole antennas, slot antennas, other antennas, hybrid antennas that are formed form antennas of two or more of these types, etc. Switches  68 B may be used in selectively coupling a desired one of the antennas into use. Because each patch antenna is located in a different position within chamber  46  relative to device under test  10 , the ability to select a desired antenna provides the test system with an opportunity to optimize signal strength. 
     Antenna support structure  82  may be formed from a planar substrate member. Antenna support structures  84  may form a rail with a slot such as slot  86  that is aligned with longitudinal axis  90  of antenna support structures  84 . A vertical fin that extends from support structures  82  may pass through slot  86 . During operation, the fin may slide within slot  86  in directions  88 , so that the position of support structures  82  may be adjusted along longitudinal axis  90  of the rail. A pneumatic positioner (see, e.g., positioner  68  of  FIG. 3 ) may be used in controlling the linear position of support structures  82  along rail  84 . 
       FIG. 8  is a top perspective view of adjustable antenna support structures  64 , showing how cable  72  may be provided with a meandering path to allow movement of antennas  66  and support structures  82  along axis  90  without over-stretching the cable. 
       FIG. 9  is a top perspective view of chamber  46  (partly in cross section), showing how adjustable antenna system  64  may be mounted in the top of chamber  46  (as an example). 
     As shown in  FIG. 10 , adjustable antenna system  64  (e.g., rail  84  and some or all of support structures  82 ) may have an interior surface that is covered by pyramidal absorbers  48 , while leaving antennas  66  exposed to the interior of chamber  46 . This may help reduce signal reflections from antenna support structures  82  and  84  in adjustable antenna system  64 . 
     Illustrative steps involved in testing devices under test using a test system such as test system  28  of  FIG. 5  are shown in  FIG. 11 . 
     At step  90 , devices under test  10  may be loaded into test stations  30 . Master test station  30 M may, in response to control commands from test equipment  60 , make adjustments to antenna position using positioner  68  in adjustable antenna system  64 , make adjustments to which antenna  66  is switched into use using switching circuitry  68 B, and may make adjustments to the position of device under test  10  in master test station  30 M using positioning system  50  (e.g., by rotating device under test  10  or otherwise moving device under test  10 ). For each different trial configuration for master test station  30 M, test equipment  60  (e.g., test equipment  60  in master test station  30 M) may make wireless test measurements such as receiver sensitivity measurements and other over-the-air measurements. The wireless test measurements allow test system  30 M to identify a satisfactory test station configuration to use in testing device under test  10  when performing subsequent single-point (fixed antenna and device location) over-the-air wireless test measurements. 
     If device under test  10  is positioned poorly relative to the active test antenna, signal strength may be inadequate for making over-the-air tests. Due to changes in communications band frequencies and other parameters during testing of device  10 , a single configuration for test system  30 M may not generally be optimal for all desired tests. As a result, master test station  30 M preferably makes adjustments to the configuration of master test station  30 M for each different communication band (or other range of frequencies) to be tests. As an example, if it is desired to test device under test  10  in a 2.4 GHz wireless local area network communications band and to test device under test  10  in a 5 GHz wireless local area network communications band, test station  30 M may make a series of adjustments to identify a first satisfactory configuration for performing single-point over-the-air tests in the 2.4 GHz band and will make another series of adjustments to identify a second satisfactory configuration for performing single-point over-the-air tests in the 5 GHz communications band. 
     Consider, as an example, a scenario in which it is desired to perform over-the-air test measurements on devices under test  10  using test system  28  of  FIG. 5 . It may be desired, for example, to measure receiver sensitivity in transceiver circuitry  42  in an operating scenario in which display  14  is active and in an operating scenario in which display  14  is inactive. It may be desirable to identify a test station configuration (e.g., a position for a test antenna) that maximizes or nearly maximizes signal strength during measurements. This configuration (i.e., this antenna location relative to chamber  46  and device under test  10 ) may then be used in making the over-the-air test measurements. 
     The test measurements that are made during the receiver sensitivity tests in slave test stations  30 S may be made so that each slave test station&#39;s test antenna is located in a single location within the test chamber of the slave test station (i.e., the test antenna may be fixed at a single optimal location based on information on this location that is provided by the master test station). This type of single-position antenna measurement may be used in performing desense measurements, coexistence measurements, equivalent isotropically radiated power (EIRP) measurements, and effective isotropic sensitivity (EIS) measurements and other single-point over-the-air measurements. 
     During the operations of step  90 , the master test station may step through each possible antenna  66 . For example, the master test station may switch antenna  66 A into use and perform measurements to determine how well signals are transmitted and received using antenna  66 A, the master test station may then switch antenna  66 B into use and perform measurements to evaluate antenna  66 B, and the master test station may then switch antenna  66 C into use and perform measurements to evaluate  66 C. Using this type of systematic evaluation technique, the master test station can determine which of the three antennas  66  in master test station  30 M produces optimum test results. While stepping through each of the available antennas, test station  30 M may also step through each of a plurality of different potential positions for antennas  66  along longitudinal axis  90  of rail  84  and/or may step through a series of different angular orientations for device under test  10  using positioning system  50 . After iterating over all desired candidate configurations for test station  30 M, a satisfactory configuration for test station  30 M and test stations  30 S (e.g., an optimum configuration in which signal strength is maximized to ensure satisfactory over-the-air wireless tests) may be identified. 
     At step  92 , the master test station may configure the slave test stations based on the test measurements made by the master test station. In particular, test equipment  60  may direct each slave test station  30 S to use the optimum test station configuration that was identified at step  90 . Test equipment  60  in the master test station may, for example, direct each slave test station  30 S to move support structure  82  and antennas  66  to a particular longitudinal position along rail  84 , may direct switching circuitry  68 B to switch a particular one of antennas  66  into use, and may direct device under test positioning system  50  to position device under test  10  in the location that was identified during step  90 . This will place all slave test stations  30 S in test system  28  in the same optimum configuration for making satisfactory wireless single-point (fixed antenna location relative to the device under test) over-the-air test measurements with test equipment  60 . 
     At step  94 , each of the slave test stations tests a respective one of the devices under test after being configured by the master test station based on the test measurements of step  90 . During the operations of step  94 , test stations  30 S may each use the satisfactory configuration in which they have been placed by test station  30 M in performing wireless tests on devices under test  10 . Test station  30 M may also perform tests if desired. In each test station, the selected antenna  66  is preferably not moved during testing (i.e., the selected antenna is at a fixed location for performing over-the-air single point tests such as desense tests, coexistence tests, EIRP tests, and EIS tests). Test results can be analyzed and used during the manufacturing of devices  10 . For example, pass-fail tests may be established by test system  28 . If a particular device under test  10  does not exhibit a desired level of performance, the device may be deemed to have failed the test and can be reworked or scrapped. Devices under test  10  that exceed minimum performance requirements may be shipped to users. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20130306
Publication Date: 20151117
Grant Date: 20151117
Priority Date: 20130306
Inventors: HERNANDEZ DIEGO C.
SEN INDRANIL
CHEN CHUN-LUNG
GOMEZ TAGLE JAVIER
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q3/267", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B17/27", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/267", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B17/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/27", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 51488423