阅读说明：本技术 Rf电缆和电缆绑定路径损耗确定方法 (RF cable and cable binding path loss determination method ) 是由 马库斯·加尔豪泽 马蒂亚斯·耶伦 马丁·厄特延 马丁·罗特 瓦尔德马·亨里希 埃斯梅拉达· 于 2019-06-27 设计创作，主要内容包括：一种RF电缆(20)包括：连接器壳体(21)，具有RF信号输出接口(25a)；电缆本体(22)，具有连接到连接器壳体(21)的第一端部和包括RF信号输入接口(26a)的第二端部；RF信号传输路径(23)，形成为从RF信号输入接口(26a)通过电缆本体(22)和连接器壳体(21)到RF信号输出接口(25)；以及功率测量设备(24)，集成在连接器壳体(21)中，并且被配置为测量通过RF信号传输路径(23)发送的RF信号的功率值。RF电缆(20)还包括：测量信号输出接口(26b；25b)；以及测量信号传输线(29a；29b)，将功率测量设备(24)连接到测量信号输出接口(26b；25b)，功率测量设备(24)被配置为在测量信号输出接口(26b；25b)处输出指示RF信号的所测量的功率值的测量信号。(An RF cable (20) comprising: a connector housing (21) having an RF signal output interface (25 a); a cable body (22) having a first end connected to the connector housing (21) and a second end including an RF signal input interface (26 a); an RF signal transmission path (23) formed from an RF signal input interface (26a) to an RF signal output interface (25) through the cable body (22) and the connector housing (21); and a power measurement device (24) integrated in the connector housing (21) and configured to measure a power value of the RF signal transmitted through the RF signal transmission path (23). The RF cable (20) further comprises: a measurement signal output interface (26 b; 25 b); and a measurement signal transmission line (29 a; 29b) connecting the power measurement device (24) to the measurement signal output interface (26 b; 25b), the power measurement device (24) being configured to output a measurement signal indicative of the measured power value of the RF signal at the measurement signal output interface (26 b; 25 b).)

1. An RF cable (20) comprising:

a connector housing (21) having an RF signal output interface (25 a);

a cable body (22) having a first end connected to the connector housing (21) and a second end comprising an RF signal input interface (26 a);

an RF signal transmission path (23) formed from the RF signal input interface (26a) to the RF signal output interface (25a) through the cable body (22) and the connector housing (21); and

a power measurement device (24) integrated in the connector housing (21) and configured to measure a power value of an RF signal transmitted through the RF signal transmission path (23),

the RF cable (20) is characterized by further comprising:

a measurement signal output interface (26 b; 25 b); and

a measurement signal transmission line (29 a; 29b) connecting the power measurement device (24) to the measurement signal output interface (26 b; 25b), the power measurement device (24) being configured to output a measurement signal indicative of the measured power value of the RF signal at the measurement signal output interface (26 b; 25 b).

2. The RF cable (20) of claim 1, wherein the measurement signal output interface (25b) is located in the connector housing (21).

3. The RF cable (20) of claim 1, wherein the measurement signal output interface (26b) is located at a second end of the cable body (22).

4. The RF cable (20) of claim 1 or 2, the power measurement device (24) comprising:

a power sensor (24a) configured to convert the RF signal to a DC or low frequency signal; and

a power meter (24b) coupled to the power sensor (24a) and configured to measure the DC or low frequency signal in order to determine a power value of the RF signal.

5. The RF cable (20) of claim 4, wherein the power sensor (24a) includes a thermistor, thermocouple, or diode detector circuit.

6. The RF cable (20) of any of claims 4 and 5, wherein the power meter (24b) is configured to convert an analog DC or low frequency signal into a digital measurement signal indicative of the measured power value of the RF signal.

7. RF cable (20) according to any of claims 1 to 6, wherein the cable body (22) and/or the connector housing (21) comprises an electromagnetic shielding barrier.

8. RF cable (20) according to any one of claims 1 to 6, comprising at least two cable cores, a first of the cable cores carrying the RF signal transmission path (23) and a second of the cable cores carrying the measurement signal transmission line (29 a; 29 b).

9. A test system (1) for testing one or more mobile communication devices (10), the test system (1) comprising:

a test controller (2) comprising a signal generator and an analyzer (7);

a test chamber (4);

one or more mobile communication devices (10) under test placed in the test chamber (4); and

the one or more RF cables (20) according to any one of claims 1 to 8, the one or more RF cables (20) interconnecting the test controller (2), the test room (4) and the one or more mobile communication devices (10) under test.

10. The test system (1) according to claim 9, wherein the test chamber (4) comprises a probe antenna (3) arranged within the test chamber (4), the probe antenna (3) being coupled to the test controller (2) by one of the RF cables (20).

11. A method (30) for determining a cable binder path loss in an RF cable (20), the method (30) comprising:

transmitting (31) an RF signal through an RF signal transmission path (23), the RF signal transmission path (23) from an RF signal input interface (26a) of the RF cable (20) through a cable body (22) to an RF signal output interface (25) of a connector housing (21) of the RF cable (20);

measuring (32), by means of a power measuring device (24) integrated in the connector housing (21), a power value of an RF signal transmitted through the RF signal transmission path (23); and

generating (33), by the power measurement device (24), a measurement signal indicative of the measured power value of the RF signal,

the method (30) is characterized by:

the generated measurement signal is output (34) at a measurement signal output interface (26 b; 25b) of the RF cable (20).

12. The method (30) according to claim 11, wherein generating (33) the measurement signal comprises: converting the RF signal into a DC or low frequency signal by a power sensor (24a) of the power measurement device (24), and measuring the DC or low frequency signal by a power meter (24b) of the power measurement device (24) in order to determine a power value of the RF signal.

13. The method (30) according to claim 11 or 12, wherein the measurement signal output interface (25b) is located in the connector housing (21).

14. The method (30) according to claim 12 or 13, wherein the measurement signal output interface (26b) is located at an end of the cable body (22), the end comprising the RF signal input interface (26 a).

Technical Field

The present invention relates to a Radio Frequency (RF) cable capable of determining power lost during transmission of an RF signal through the RF cable. Furthermore, the present invention relates to a method for determining cable-bound path loss. These methods and RF cables can be used in particular for radio communication test systems and for radio interface testing of mobile communication devices.

Background

Electronic devices, such as mobile communication devices, undergo various electronic tests after production. These tests are often necessary to ensure proper configuration, calibration, and function of the various elements of the Device Under Test (DUT). For testing purposes, a specific testing device is employed which simulates the test environment under predefined test conditions. For example, the test apparatus may employ one or more specific test routines with a predefined test schedule. Those test schedules typically involve: inputting a particular test signal sequence into the DUT and/or receiving a response to a test signal input to the DUT. Such responses may be evaluated for consistency, constancy, timeliness, and other properties of the expected behavior of the DUT.

Cables are commonly used to transmit test signals between the test equipment and the DUT. RF signals transmitted over these cables are attenuated on the way from the test equipment to the DUT and back. To compensate for the varying path loss, it is necessary to know in the test equipment the estimate or measurement of the actual path loss experienced at a particular test setting.

One possibility is to perform the measurement specifically for the cable concerned in a specific setting. For example, a separate path loss determination device may be connected to the cable used. To perform individual measurements, the cables need to be separated from the test setup, which makes the process for preparing accurate test solutions more complex and expensive.

Other approaches attempt to eliminate the need for a separate measurement device. For example, document US 2011/0077884 a1 discloses a signal retrieval circuit formed in a disc (disk) located within a coaxial cable connector, which signal retrieval circuit is capable of monitoring signal parameters of a signal transmitted through the coaxial cable connector. US 2010/0112866 a1 discloses a system and method for sensing information (e.g., voltage, current, or data) transmitted through a connector. US 2011/0161050 a1 discloses a coaxial cable connector having an internal physical parameter sensing circuit configured to sense a physical parameter of the connector and a status output component.

However, it is desirable to find a solution that more easily and comfortably determines the path loss in an RF cable (e.g., an RF cable connecting a test apparatus and a device under test or a test device to each other).

Disclosure of Invention

In accordance with the present disclosure, an RF cable and method for determining cable binder path loss may be implemented. In particular, such RF cables and methods may be applied in test systems for mobile communication devices.

Specifically, according to a first aspect of the present invention, an RF cable (e.g., for connecting a test device to a mobile communication device under test) includes: a connector housing having an RF signal output interface; a cable body having a first end connected to the connector housing and a second end including an RF signal input interface; an RF signal transmission path formed from the RF signal input interface to the RF signal output interface through the cable body and the connector housing; and a power measuring device integrated in the connector housing and configured to measure a power value of the RF signal transmitted through the RF signal transmission path. The RF cable further includes: a measurement signal output interface; and a measurement signal transmission line connecting the power measurement device to the measurement signal output interface, the power measurement device being configured to output a measurement signal at the measurement signal output interface indicative of the measured power value of the RF signal.

According to a second aspect of the invention, a test system for testing one or more mobile communication devices comprises: a test controller including a signal generator and an analyzer; a test chamber; one or more mobile communication devices under test placed in a test chamber; and one or more RF cables according to the first aspect of the invention interconnecting the test controller, the test room and the one or more mobile communication devices under test.

According to a third aspect of the present invention, a cable bonding path loss determination method includes: transmitting an RF signal through an RF signal transmission path from an RF signal input interface of the RF cable through the cable body to an RF signal output interface of the connector housing of the RF cable; measuring, by a power measuring device integrated in the connector housing, a power value of the RF signal transmitted through the RF signal transmission path; and generating, by the power measurement device, a measurement signal indicative of the measured power value of the RF signal. The method also involves: the generated measurement signal is output at a measurement signal output interface of the RF cable.

One idea of the invention is: cable bound power losses within the RF cable itself are determined without having to disconnect the cable from the interconnect device for external power measurements. By measuring the power value of the RF signal transmitted through the RF cable directly at the output portion of the RF signal, cumbersome and time-consuming unplugging and reinserting operations for connecting to an external power meter are no longer required. No other cables or other communication means are required as the measurement results are transmitted within the same RF cable.

In addition to this, there are several specific advantages associated with such RF cables, their use in test systems, and corresponding methods of determining cable binder path loss. The overall device will become smaller and cheaper. Additionally, the determination of path loss may be performed in real time without having to rely on separate power measurements between test operations.

Specific embodiments of the invention are set forth in the dependent claims.

The above and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

Drawings

Further details, aspects and embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

FIG. 1 schematically shows a test system for testing a DUT according to an embodiment of the invention.

Fig. 2 schematically illustrates an RF cable for a test system according to another embodiment of the present invention.

Fig. 3 shows a flow diagram of process stages of a method for determining cable binder path loss according to another embodiment of the invention.

In all the figures of the drawings, features and components which are identical or at least have the same function are provided with the same reference numerals, unless explicitly stated otherwise.

Detailed Description

Mobile communication devices within the contemplation of the present invention include any mobile electronic device capable of wireless communication via a mobile communication network. Mobile communication devices may include laptop computers, notebook computers, tablet computers, smart phones, mobile phones, pagers, PDAs, digital cameras, digital video cameras, portable media players, game consoles, virtual reality glasses, mobile PCs, mobile modems, machine-to-machine (M2M) devices, and similar electronic devices.

Fig. 1 schematically shows a test system 1. The test system 1 may for example be an over-the-air (OTA) test system which is capable of executing a measurement scheme for testing the radio communication capability of the electronic device under test. In particular, the test system 1 may be a two-phase (RTS) MIMO OTA measurement scheme enabling radiation. The test system 1 may be used as a general purpose tester for testing the air interface of a wireless device during all stages of product development and production, thereby supporting all common cellular and non-cellular wireless technologies, including broadcast technologies, satellite navigation and wireless connectivity technologies. Among these, there may be specific protocols, e.g. GPS, LTE FDD/TDD, Mobile WiMAX^TM、TD-SCDMA、

WCDMA/HSPA, HSPA +, GSM, GPRS, EDGE evolution, WLAN a/b/g/n,

DVB-T, CMMB, FM stereo, and T-DMB.

The test system 1 may be particularly configured and adapted to perform a test method 20 as shown in fig. 3 below and explained in connection with fig. 3. The test system 1 includes a test controller 2 coupled to one or more antennas in a test chamber 4. The test chamber 4 may for example be an anechoic chamber, the inner walls of which may be covered with an anechoic material. Within the test chamber 4 may be arranged a probe antenna 3, the probe antenna 3 being coupled to the test controller 2 and controlled by the test controller 2. To this end, the test controller 2 may include: a signal generator and analyzer 7 configured to generate a signal P to be transmitted via the probe antenna 3 and to process a signal B received via the probe antenna 3. The test controller 2 may for example be adapted to maintain a probing link PL to the probing antenna 3. Of course, there may be more than one probing antenna 3, and the probing antenna 3 may also be implemented as an antenna array (e.g. a MIMO antenna array).

The signal generator and analyzer 7 may function as a test front end module that can be operatively connected to one or more mobile communication devices 10 under test. The test controller 2 may control the signal generator and analyzer 7 to output a test signal or a reception probe signal in order to measure a gain level of an antenna or an antenna state pattern set in the mobile communication device 10. The signal generator and analyzer 7 may generally comprise one or more Vector Signal Generators (VSGs) for generating and outputting test signals to the mobile communication device 10 operatively connected to the test controller 2. Further, the signal generator and analyzer 7 may comprise one or more Vector Signal Analyzers (VSAs) for receiving, filtering and evaluating test response signals from the mobile communication device 10 as a response to one of the test signals output by the VSG. The test controller 2 may specifically emulate a base station of a mobile communication network for testing the appropriate functionality of the connected mobile communication device 10 in terms of network provisioning, network accessibility and network communication.

The test controller 2 may also be configured to measure spatially resolved gain values and/or antenna patterns of antennas in the mobile communication device 10. For example, if the mobile communication device 10 includes an active phased Antenna Array (AAS), the test controller 2 may be configured to measure the antenna pattern of the AAS according to the beamforming/beam steering settings of the AAS in the mobile communication device 10. To this end, the mobile communication device 10 may be mounted on a three-dimensional rotatable mounting platform 8, which mounting platform 8 allows the mobile communication device 10 to be oriented in any spatial orientation within the test chamber 4 as desired. The rack platform 8 may be controlled by a platform controller 9 outside the test chamber 4, the platform controller 9 being configured to position the mobile communication device 10 in any desired spatial orientation.

The platform controller 9 is coupled back to the test controller 2 in order to be able to control the platform controller 9 according to a predefined spatial orientation pattern schedule. For example, the test controller 2 may be configured to set the beamforming properties of the AAS of the mobile communication device 10 to predefined settings maintained via the probe antenna 3 during an antenna mode measurement schedule during which the platform controller 9 is controlled to set the gantry platform 8 to scan a predefined spatially directed mode schedule. In this way, the test controller 2 may collect a set of angle and spatially resolved gain maps for antennas in the AAS of the mobile communication device 10 as a function of a set of beamforming properties of the AAS. Of course, the test controller 2 may instruct the platform controller 9 to position the mobile communication device 10 in a particular way also according to other test scenario conditions.

Data collected on the mobile communication device 10 in the test mode for antenna or antenna mode measurements may be communicated to the test controller 2 OTA. For this purpose, an uplink antenna 5 may be additionally placed in the test room 4 in order to maintain an active uplink air interface TL during antenna or antenna mode measurements. For example, during or after testing, data may be transferred from the mobile communication device 10 to the test controller 2 using an IP data connection with the associated client application.

The test system 1 may further include: a channel emulator 6 configured to emulate a communication channel of a base station with the mobile communication device 10. The simulated communication channel is designed to match the actual conditions of communication between the mobile communication device 10 and a real base station. The simulation of the communication channel is performed by a channel model generator 6b, which channel model generator 6b generates a channel model to be fed to a signal generator and analyzer 7 of the test controller 2 for transmitting the test signal to the mobile communication device 10.

The channel model may be based on a fading profile generated by a fading profile generator 6a coupled to the channel model generator 6 b. Fading profile generator 6a may be configured to generate a fading profile based on a pre-stored basic fading profile. Those basic fading profiles may for example be normalized fading profiles, which represent typical fading conditions in a predetermined environment, such as an Urban Macro (UMa) or an Urban Micro (UMi).

To communicate signals between the different components of the test system 1 (e.g., between the channel simulator 6 and the test controller 2, between the test controller 2 and the probe antenna, between the test controller 2 and the platform controller 9, between the platform controller 9 and the platform support 8, between the test controller 2 and the mobile communication device 10, and between the channel simulator 6 and the mobile communication device 10), RF cables 20 may be employed. For example, if a signal from the channel emulator 6 is to be sent to the mobile communication device 10, an RF cable 20 may be connected between the output of the channel emulator 6 and the temporary antenna connector of the mobile communication device 10. The same is true for signals sent between test controller 2 and probe antenna 3, where RF cable 20 may be connected between the output of test controller 2 and the input of test room 4.

Fig. 2 schematically depicts an RF cable 20 in a functional diagram. The actual dimensions of the RF cable 20 may not be to scale as shown in fig. 2. In particular, the RF cable 20 shown in FIG. 2 may be employed in order to connect components of the test system 1 (as depicted and described in connection with FIG. 1). Further, the RF cable 20 of fig. 2 may be used in a method of determining cable binder path loss, as described and illustrated in connection with fig. 3.

The RF cable 20 generally includes a cable body 22 having a first end and a second end. The first end terminates in a connector housing 21 having an RF signal output interface 25 a. The second end of the cable body may have an RF signal input interface 26 a. RF signals may be transmitted from the RF signal input interface 26a to the RF signal output interface 25 through the cable body 22 and the connector housing. For example, the RF signal input interface 26a may be connected to an RF port of the test controller 2 (or another component of the test system 1). The RF cable 20 may be used to transmit RF signals from the test controller 2 to the mobile communication device 10 to be tested, i.e. the RF signal output interface 25 may be connected to a corresponding input port of the mobile communication device 10.

Accordingly, the RF signal is transmitted on the RF signal transmission path 23 within the RF cable 20. To this end, the RF cable 20 may be electromagnetically shielded, for example by providing the cable body 22 and/or the connector housing 21 with an electromagnetic shielding barrier. The RF signal transmission path 23 may be implemented with a dedicated cable core carrying the RF signal transmission path 23.

The connector housing 21 has an integrated power measuring device 24. The power measuring device 24 is used to measure the power value of the RF signal transmitted through the RF signal transmission path 23. The power measurement device 24 may, for example, include a power sensor 24a and a power meter 24b coupled to the power sensor 24 a. The power sensor 24a may be, for example, a thermistor, thermocouple, or diode detector circuit. These components may convert the RF signal on the RF signal transmission path 23 into a DC or low frequency signal. The power meter 24b may then measure the converted DC or low frequency signal and may determine a current or instantaneous power value of the RF signal from the value of the DC or low frequency signal. In particular, the power meter 24b may be used to output a digital measurement signal indicative of the measured power value of the RF signal. The power meter 24b may comprise a general purpose processor such as a central processing unit, ASIC, FPGA or any similar programmable logic device.

The RF cable 20 also includes one or more measurement signal output interfaces. This measurement signal output interface is a physical interface of the RF cable 20, such as an additional pin, cable core or transmission line of the RF cable 20. For example, the measurement signal output interface 25b may be located in the connector housing 21 in parallel with the RF signal output interface 25 a. Alternatively or additionally, the measurement signal output interface 26b may be located at the second end of the cable body 22, i.e. parallel to the RF signal input interface 26 a.

One or more measurement signal transmission lines 29a, 29b connect the power measurement device 24 to the measurement signal output interfaces 26b, 25b, respectively. The power measurement device 24 may output a measurement signal at one or both of the measurement signal output interfaces 26b, 25b indicative of the measured power value of the RF signal. The measurement signal transmission lines 29a, 29b may be formed on a dedicated cable core of the RF cable 20. The dedicated cable core may be a separate cable core from the cable core carrying the RF signal transmission path 23.

The RF signal input interface 26a may implement a splitter function, i.e., the portion of the RF signal to be transmitted through the RF signal transmission path 23 is split from the RF signal and routed directly to the power sensor 24a through the sensor line 20 in the RF cable. In this way, the RF signal transmission path 23 may remain substantially undisturbed and the measurements of the power measurement device 24 may be more accurate.

To ensure proper functioning and desired characteristics of the antenna, it may be desirable to test a mobile communication device, such as the mobile communication device 10 of fig. 1, for the antenna after manufacture and before shipping. Such a test may be performed with the test system 1 of fig. 1. To determine the cable binder path loss in the RF cable used to connect the test devices to each other and/or to connect the test devices to the mobile communication device under test 10, a method 30 may be implemented as further described below in connection with fig. 3. The mobile communication device 10 of fig. 1 may be used as a Device Under Test (DUT) for a test system 1 in which an RF cable 20 as depicted and described in connection with fig. 2 is installed.

In the first stage 31, the RF signal is transmitted through the RF signal transmission path 23, the RF signal transmission path 23 being from the RF signal input interface 26a of the RF cable 20 to the RF signal output interface 25 of the connector housing 21 of the RF cable 20 through the cable body 22. In the second stage 32, the power measuring device 24 integrated in the connector housing 21 is used to measure the power value of the RF signal transmitted through the RF signal transmission path 23.

In the third stage 33, the power measurement device 24 generates a measurement signal indicating the measured power value of the RF signal. This generation may be accomplished, for example, by converting the RF signal to a DC or low frequency signal (e.g., by using a power sensor 24a of the power measurement device 24, such as a thermistor, thermocouple, or diode detector circuit). The converted DC or low frequency signal may then be measured by the power meter 24b of the power measurement device 24 to determine the power value of the RF signal.

In a fourth stage 34, the method 30 involves outputting the generated measurement signal at a measurement signal output interface of the RF cable 20. The measurement signal output interface may be located, for example, in the connector housing 21. Alternatively, the measurement signal output interface may be located at an end of the cable body 22 that includes the RF signal input interface 26 a. In particular, the measurement signal output interface may be a physical interface of the RF cable 20, such as another pin, cable core or transmission line of the RF cable 20.

In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. For example, the connections between the various elements shown and described in the figures may be of a type suitable for transmitting signals to and from the various nodes, units or devices, e.g., via intermediate devices. Thus, unless implied or stated otherwise, the connections may be, for example, direct connections or indirect connections.

Because the apparatus implementing the present invention is, for the most part, composed of electronic components and circuits known to those skilled in the art, circuit and component details will not be explained in any greater extent than that considered necessary as illustrated above, for the understanding and appreciation of the underlying concepts of the present invention and in order not to obfuscate or distract from the teachings of the present invention.

Furthermore, the invention is not limited to physical devices or units implemented in non-programmable hardware, but can also be applied in programmable devices or units capable of performing the desired device functions by operating in accordance with suitable program code. Further, the apparatus may be physically distributed over a plurality of devices while functionally operating as a single apparatus. Devices that functionally form separate devices may be integrated into a single physical device. Furthermore, those skilled in the art will recognize that the boundaries between logic or functional blocks are merely illustrative and that alternative embodiments may merge logic or functional blocks or impose an alternate decomposition of functionality upon various logic or functional blocks.

In the description, any reference signs shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. Furthermore, the terms "a" or "an," as used herein, are defined as one or more than one. Furthermore, the use of introductory phrases such as "at least one" and "one or more" in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an". The same holds true for the use of definite articles. Unless otherwise specified, terms such as "first" and "second" are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The order in which the method steps are recited in the claims does not imply a loss of order in which the steps are actually performed unless specifically recited in the claim.

Those skilled in the art will appreciate that the illustrations of selected elements in the figures are merely intended to facilitate a better understanding of the function and arrangement of such elements in various embodiments of the present invention. Further, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be appreciated that certain process stages in the described methods may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.