Radio frequency module and electronic device
By setting a second RF seat on the circuit board of the electronic device and coupling it with the RF circuit, the discontinuity and insertion loss problems caused by the RF signal path passing through the circuit board are solved, and the RF conduction performance is improved.
Patent Information
- Application Number
- CN202411772771.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-03-18
AI Technical Summary
In the RF module of electronic devices, the RF signal path needs to pass through the circuit board, resulting in discontinuity of the RF trace, increasing insertion loss, and affecting the RF conduction performance.
By providing a second RF base on the second side of the circuit board and coupling with the RF circuit, the RF signal path is prevented from passing through the circuit board, thereby eliminating the discontinuity of the trace and insertion loss.
The RF conduction performance is improved, the discontinuity and insertion loss of RF traces are avoided, and the transmission efficiency of RF signals is enhanced.
Smart Images
Figure CN119652330A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of electronic equipment, and specifically relates to a radio frequency module of an electronic equipment and an electronic equipment. Background Art
[0002] In the related art, for electronic devices with mobile communication functions such as mobile phones, the quality of their communication performance will directly affect the user experience. For the transceiver circuit of RF signals, after the RF architecture and components are selected, the routing loss of the printed circuit board (PCB) will directly determine the RF conduction performance.
[0003] During the development of electronic equipment, the RF path needs to be calibrated, and the conduction performance of the RF signal needs to be tested later, so an RF socket needs to be set up on the PCB. Since the test points of the PCB are generally on the back (bottom surface), and the front (top surface) in the test fixture is used for support, the RF socket can only be laid out on the bottom surface, while the RF circuit may be laid out on the top surface of the PCB. Therefore, when the RF circuit is located on the top surface of the PCB, the RF signal path needs to be punched, from the top surface through the PCB to the bottom surface and through the RF socket to connect to the antenna. This results in the signal transmission needing to go through the punching routing every time the RF signal communicates. Since the impedance of the PCB punching routing at the PCB via position is discontinuous, the via will cause the discontinuity of the RF routing, resulting in increased insertion loss and affecting the RF conduction performance. Summary of the invention
[0004] The present application aims to provide a radio frequency module of an electronic device and an electronic device, which can improve the radio frequency conduction performance of the radio frequency module.
[0005] In a first aspect, an embodiment of the present application provides a radio frequency module of an electronic device, the electronic device includes a circuit board, the circuit board includes a first surface and a second surface, and the radio frequency module includes:
[0006] A radio frequency circuit, the radio frequency circuit is arranged on the first surface, and the radio frequency circuit is electrically connected to the radio frequency antenna through a first electrical path;
[0007] A second electrical path, the second electrical path is arranged on the first surface, the second electrical path is connected in parallel with the first electrical path, and the second electrical path is used to connect to the first radio frequency socket; wherein, when the second electrical path is connected to the first radio frequency socket, the second electrical path conducts the first radio frequency socket and the radio frequency antenna;
[0008] The second radio frequency socket is arranged on the second surface of the circuit board and is coupled to the radio frequency circuit.
[0009] In a second aspect, an embodiment of the present application provides an electronic device, comprising a radio frequency module as provided in the first aspect.
[0010] In the embodiment of the present application, during the development stage, by installing the first RF socket on the second electrical path, the calibration parameters of the RF path are obtained through the first RF socket. In the subsequent production process, the first RF socket no longer needs to be installed, and the RF circuit and the RF antenna transmit the RF signal through the first electrical path. The second RF socket is used to test the conduction performance of the RF signal. The second RF socket is coupled and connected to the RF circuit, so the RF signal path does not need to pass through the second RF socket, which means that even if the second RF socket is set on the other side of the circuit board, the RF routing no longer needs to pass through the circuit board, which will not cause discontinuity of the RF routing and will not increase insertion loss, thereby improving the RF conduction performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:
[0012] Figure 1 One of the circuit structure schematic diagrams of the radio frequency module of the electronic device in some embodiments of the present application is shown;
[0013] Figure 2 One of the structural schematic diagrams of electronic devices in some embodiments of the present application is shown;
[0014] Figure 3 A second schematic diagram of the circuit structure of a radio frequency module of an electronic device in some embodiments of the present application is shown;
[0015] Figure 4 A third schematic diagram of the circuit structure of the radio frequency module of the electronic device in some embodiments of the present application is shown;
[0016] Figure 5A A second structural schematic diagram of an electronic device according to some embodiments of the present application is shown;
[0017] Figure 5B A third structural schematic diagram of an electronic device according to some embodiments of the present application is shown.
[0018] Reference numerals:
[0019] 100 RF module, 102 RF circuit, 104 first electrical path, 106 second electrical path, 108 first RF socket, 110 second RF socket, RF_TRX RF signal transceiver trace, RF_CPL coupling trace, T1 selection switch, T2 switch device, ANT RF antenna, R resistive element, 114 first connector, 116 adapter board, 1162 second connector, 1164 third RF socket;
[0020] 200 electronic device, 202 circuit board, 2022 first side, 2024 second side. DETAILED DESCRIPTION
[0021] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.
[0022] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.
[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0024] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0025] Combine the following Figures 1 to 5B A radio frequency module of an electronic device and an electronic device according to an embodiment of the present application are described.
[0026] In some embodiments of the present application, a radio frequency module 100 of an electronic device 200 is provided. Figure 1 One of the circuit structure diagrams of the radio frequency module of the electronic device in some embodiments of the present application is shown, Figure 2 One of the structural schematic diagrams of electronic devices in some embodiments of the present application is shown, such as Figure 1 and Figure 2 As shown, the electronic device 200 includes a circuit board 202, the circuit board 202 includes a first surface 2022 and a second surface 2024, and the radio frequency module 100 includes:
[0027] The RF circuit 102 is provided on the first surface 2022, and the RF circuit 102 is electrically connected to the RF antenna ANT through the first electrical path 104; the second electrical path 106 is provided on the first surface 2022, and the second electrical path 106 is connected in parallel with the first electrical path 104, and the second electrical path 106 is used to connect the first RF socket 108; wherein, when the second electrical path 106 is connected to the first RF socket 108, the second electrical path 106 conducts the first RF socket 108 and the RF antenna ANT; or, when the second electrical path is not connected to the first RF socket, the second electrical path 106 disconnects the first RF socket 108 and the RF antenna ANT; the second RF socket 110 is provided on the second surface 2024 of the circuit board 202, and the second RF socket 110 is coupled to the RF circuit 102.
[0028] In the embodiment of the present application, the electronic device 200 includes but is not limited to a mobile phone, a smart bracelet, a smart watch, a tablet computer, smart glasses, a handheld game console, etc. The electronic device 200 includes a circuit board 202, which can be a mainboard of the electronic device 200 or other circuit boards, such as a radio frequency communication circuit board.
[0029] The first surface 2022 of the circuit board 202 is defined as the top surface, and the second surface 2024 of the circuit board 202 is defined as the bottom surface. The RF circuit 102 is arranged on the first surface 2022 of the circuit board 202, that is, the top surface, and the RF circuit 102 is electrically connected to the RF antenna ANT through the first electrical path 104. The second electrical path 106 is connected in parallel with the first electrical path 104, and the first RF socket 108 can be connected to the second electrical path 106. When the first RF socket 108 is installed, the first RF socket 108 is located on the top surface, and the RF signal will pass through the first electrical path 104 and the second electrical path 106 at the same time.
[0030] Exemplarily, the first RF socket 108 and the second RF socket 110 both include a test socket housing, a probe and a RF coaxial connector.
[0031] During the development phase, the RF path needs to be calibrated and marked to obtain the calibration parameters of the RF path. At this time, the first RF socket is connected to the second electrical path 106 by welding or other means, and the calibration parameters of the current RF path are calibrated through the first RF socket test.
[0032] After the calibration parameters are obtained, they are solidified in the memory of the electronic device 200. At this time, the first RF socket is no longer needed, that is, it is no longer necessary to install the first RF socket in the second electrical path 106 during mass production. At this time, the second electrical path 106 is in an open circuit state, and the RF circuit 102 is electrically connected to the RF antenna ANT only through the first electrical path 104.
[0033] A second RF socket is disposed on the second surface 2024, i.e., the bottom surface, of the circuit board 202. The second RF socket is used to test the conduction performance of the RF signal. The second RF socket is disposed on the bottom surface because the test points of the conventional circuit board 202 are all on the bottom surface. The second RF socket is connected to the RF circuit 102 by coupling, i.e., there is no need to directly connect the RF circuit 102 and the second RF socket.
[0034] During the test phase, by measuring parameters such as routing coupling degree and routing loss, the corresponding results of the signal power obtained by the second RF socket after coupling and the actual signal power are obtained. For example, the signal power obtained by the first RF socket and the signal power obtained by the second RF socket under the same conditions are recorded and stored in the form of a table. Therefore, in subsequent production, only the second RF socket is needed to determine the performance of the RF path.
[0035] Since the second RF socket is coupled to the RF circuit 102, during the operation of the electronic device 200, the RF signal path does not need to pass through the second RF socket. This means that even if the second RF socket 110 is set on the other side of the circuit board 202, the RF wiring no longer needs to pass through the circuit board 202, which will not cause discontinuity of the RF wiring and increase insertion loss, thereby improving the RF conduction performance.
[0036] In some embodiments of the present application, Figure 1 and Figure 2 As shown, the RF module 100 also includes: an RF signal transceiver trace RF_TRX, the RF signal transceiver trace RF_TRX is electrically connected to the RF circuit 102, and the other end of the RF signal transceiver trace RF_TRX is electrically connected to the first electrical path (104) and / or the second electrical path (106); a coupling trace RF_CPL, the coupling trace RF_CPL is electrically connected to the second RF socket 110, and at least the routing direction of the coupling trace RF_CPL is parallel to the routing direction of the RF signal transceiver trace RF_TRX.
[0037] In the embodiment of the present application, the RF signal transceiver trace RF_TRX is a trace connecting the RF circuit 102 and the first electrical path 104, the coupling trace RF_CPL is electrically connected to the second RF socket, and at least a portion of the coupling trace RF_CPL is parallel to the RF signal transceiver trace RF_TRX. When the RF signal is transmitted in the RF signal transceiver trace RF_TRX, the signal in the RF signal transceiver trace RF_TRX can be coupled to the coupling trace RF_CPL, thereby achieving a test result on the second RF socket.
[0038] Since the coupling trace RF_CPL and the RF signal transceiver trace RF_TRX are coupled and connected, they are not physically connected in fact. Therefore, they will not affect the RF signal path during normal use, thereby improving the RF conduction performance while realizing the RF performance test function.
[0039] In some embodiments of the present application, Figure 1 and Figure 2 As shown, the radio frequency signal transceiver trace RF_TRX and the coupling trace RF_CPL are located on different layers of the circuit board 202 .
[0040] In this technical solution, the circuit board 202 of the electronic device 200 is a multi-layer circuit board 202, that is, a multi-layer PCB structure. The radio frequency signal transceiver trace RF_TRX and the coupling trace RF_CPL are respectively routed in different PCB layers of the circuit board 202. Exemplarily, when the circuit board 202 is placed horizontally, part of the radio frequency signal transceiver trace RF_TRX and part of the coupling trace RF_CPL overlap in the height direction of the circuit board 202.
[0041] Exemplarily, the circuit board 202 is a 20-layer structure, wherein the RF signal transceiver trace RF_TRX is on the 12th layer of the PCB, and the coupling trace RF_CPL is on the 11th layer of the PCB. Exemplarily, the RF signal transceiver trace RF_TRX is parallel to the coupling trace RF_CPL and the trace length that overlaps in the height direction of the circuit board 202 is not less than 1.8 mm.
[0042] The present application parallelly routes the RF signal transceiver trace RF_TRX and the coupling trace RF_CPL on different PCB layers of the circuit board 202, so that the second RF socket 110 can be coupled to the RF circuit 102 to achieve testing of the RF path performance.
[0043] In some embodiments of the present application, Figure 1As shown, there are multiple RF circuits 102; the RF module 100 also includes: a selection switch T1, the RF signal transceiver line RF_TRX is connected to one RF circuit 102 through the selection switch T1, and the selection switch T1 is used to switch the connection status between the RF signal transceiver line RF_TRX and multiple RF circuits 102.
[0044] In the embodiment of the present application, there are multiple RF circuits 102. For example, the multiple RF circuits 102 correspond to RF signals of different frequencies. The RF module 100 also includes a selection switch T1, which selects one of the RF circuits 102 to connect with the RF signal transceiver routing RF_TRX, thereby switching the signal frequency.
[0045] Wherein, illustratively, the selection switch T1 is a relay, and the selection switch T1 includes a moving contact and multiple static contacts, each RF circuit 102 is electrically connected to a static contact, and the moving contact is electrically connected to the RF signal transceiver line RF_TRX. By switching the connection mode between the moving contact and the multiple static contacts, the selection and switching of RF circuits 102 of different frequencies can be realized, so that the RF performance of multiple RF circuits of different frequencies can be tested through a single coupling between the RF signal transceiver line RF_TRX and the coupling line RF_CPL.
[0046] In some embodiments of the present application, Figure 3 The second circuit structure diagram of the radio frequency module of the electronic device of some embodiments of the present application is shown, such as Figure 3 As shown, the RF module 100 also includes: a switching device T2, the switching device T2 includes at least two first ports and a second port, and the second port can be connected to one of the first ports; wherein, at least one first port is electrically connected to the RF circuit 102, at least one first port that is not electrically connected to the RF circuit 102 is electrically connected to the second RF socket 110, and the second port is electrically connected to the RF signal transceiver trace RF_TRX.
[0047] In this technical solution, the second RF socket 110 and the RF circuit 102 are coupled and connected through different switch terminals of the switch device T2. Exemplarily, the switch device T2 includes a first port and a second port, wherein the number of the first ports is at least two, at least one of which is electrically connected to the RF circuit 102, and at least one of which is electrically connected to the second RF socket 110.
[0048] The second port is electrically connected to the RF antenna ANT, and the second port is connected to at least one first port connected to the RF circuit 102. When there are multiple RF circuits 102, the second port can be switched to be connected to one of the first ports, and the coupling between the second RF socket 110 and the RF circuit 102 is achieved through port coupling of the switch device T2.
[0049] In some embodiments of the present application, Figure 3 As shown, the number of RF circuits 102 is N, where N is a positive integer; the number of first ports is M, where M is a positive integer greater than N; wherein N first ports among the M first ports are electrically connected to the N RF circuits 102 respectively; among the M first ports, one first port other than the N first ports electrically connected to the N RF circuits 102 is electrically connected to the second RF socket 110.
[0050] In the embodiment of the present application, illustratively, it is assumed that N=4, M=2, that is, the switch device T2 has four first ports, which are respectively denoted as RF1, RF2, RF3 and RF4. The number of RF circuits 102 is 2. The second port is denoted as RF_ANT, wherein RF1 and RF3 are electrically connected to the two RF circuits 102 respectively, RF4 is electrically connected to the second RF socket 110, and RF2 is vacant. Then RF_ANT can be connected to RF1 or RF3, so as to transmit the RF signal to the RF antenna ANT for transmission. RF4 is isolated from RF1, RF3 and RF_ANT, and the RF signal is coupled to the RF4 port at the RF1 or RF3 port, and the coupled energy can be transferred to the second RF socket 110, so as to complete the RF test on the second RF socket 110.
[0051] In some embodiments of the present application, the switch device T2 is a single-pole multi-throw switch; or, Figure 4 The third circuit structure diagram of the radio frequency module of the electronic device of some embodiments of the present application is shown, Figure 4 As shown, the switching device T2 is a coupler.
[0052] In the embodiment of the present application, the coupling between the switch ports of the single-pole multi-throw switch can be used to realize the coupling connection between the second RF socket 110 and the RF circuit 102. In other embodiments, the isolation of the coupler port can also be used to realize the coupling connection and physical isolation connection between the second RF socket 110 and the RF circuit 102.
[0053] In some embodiments of the present application, the first electrical path 104 includes a resistive element R, and the resistive element R is connected in series between the RF circuit 102 and the RF antenna ANT.
[0054] In the embodiment of the present application, a resistive element R is connected in series in the first electrical path. For example, the resistive element R can be a resistor device, or it can refer to the line resistance of the connecting line. When the first RF socket is not installed in the second electrical path, the RF circuit 102 is connected to the RF antenna ANT through the first electrical path and the resistive element R in the first electrical path. In order to avoid increasing the loss of the RF path, the resistance value of the resistive element R is small. For example, the resistive element R is a 0Ω resistor.
[0055] In some embodiments of the present application, Figure 5A and Figure 5B The schematic diagram of the structure of the electronic device of some embodiments of the present application is shown as follows: Figure 5A and Figure 5B As shown, the RF module 100 also includes: a first connector 114, which is arranged on the second surface 2024 and is electrically connected to the RF circuit 102; an adapter board 116, on which a second connector 1162 and a third RF socket 1164 are arranged, and the second connector 1162 can be connected to the first connector 114 to connect the RF circuit 102 to the third RF socket 1164.
[0056] In the embodiment of the present application, the electronic device 200 includes but is not limited to a mobile phone, a smart bracelet, a smart watch, a tablet computer, smart glasses, a handheld game console, etc. The electronic device 200 includes a circuit board 202, which can be a mainboard of the electronic device 200 or other circuit boards, such as a radio frequency communication circuit board.
[0057] The first surface 2022 of the circuit board 202 is defined as the top surface, and the second surface 2024 of the circuit board 202 is defined as the bottom surface. The RF circuit 102 and the RF antenna ANT are both arranged on the first surface 2022 of the circuit board 202, that is, the top surface. The RF circuit 102 is electrically connected to the RF antenna ANT. At this time, the RF signal path is all located on the top surface, and there is no need to route to the bottom surface, which can ensure the RF performance.
[0058] Since the test points of the conventional circuit board 202 are all on the bottom surface, the first connector 114 needs to be set on the bottom surface. In this regard, the present application sets an adapter board 116, on which a second connector 1162 and a third RF socket 1164 are set. The second connector 1162 can be connected to the first connector 114 to achieve the transmission of RF signals.
[0059] Exemplarily, both the first connector 114 and the second connector 1162 are RF coaxial connectors. Exemplarily, the first connector 114 may be a female connector of the RF coaxial connector, and the second connector 1162 may be a male connector of the RF coaxial connector.
[0060] When testing, the adapter board 116 is connected to the circuit board 202. At this time, the first connector 114 is connected to the second connector 1162, so that the first connector 114 located on the bottom surface is transferred to the top surface, so as to be tested together with other RF sockets on the top surface. The RF performance is tested without punching holes in the circuit board 202 or passing the RF wiring through the circuit board 202, thereby improving the RF conduction performance.
[0061] In some embodiments of the present application, an electronic device is provided, which includes a radio frequency module of an electronic device as provided in any of the above embodiments. Therefore, the electronic device also includes all the beneficial effects of the radio frequency module of the electronic device provided in any of the above embodiments. To avoid repetition, they are not repeated here.
[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0063] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A radio frequency module for an electronic device, characterized in that: The electronic device comprises a circuit board, the circuit board comprises a first surface and a second surface, and the radio frequency module comprises: A radio frequency circuit, the radio frequency circuit is arranged on the first surface, and the radio frequency circuit is electrically connected to the radio frequency antenna through a first electrical path; a second electrical path, the second electrical path being arranged on the first surface, the second electrical path being connected in parallel with the first electrical path, and the second electrical path being used to connect to the first RF socket; wherein, when the second electrical path is connected to the first RF socket, the second electrical path conducts between the first RF socket and the RF antenna; The second radio frequency socket is arranged on the second surface of the circuit board, and the second radio frequency socket is coupled to the radio frequency circuit.
2. The radio frequency module according to claim 1, characterized in that: The radio frequency module also includes: A radio frequency signal transceiver wiring, one end of which is electrically connected to the radio frequency circuit, and the other end of which is electrically connected to the first electrical path and / or the second electrical path; A coupling trace, wherein the coupling trace is electrically connected to the second RF socket, and a routing direction of at least a portion of the coupling trace is parallel to a routing direction of the RF signal transceiver trace.
3. The radio frequency module according to claim 2, characterized in that: The radio frequency signal transceiver wiring and the coupling wiring are respectively located on different layers of the circuit board.
4. The radio frequency module according to claim 2, characterized in that: The number of the radio frequency circuits is multiple; the radio frequency module also includes: A selection switch, wherein the RF signal transceiver wiring is connected to one of the RF circuits through the selection switch, and the selection switch is used to switch the connection status between the RF signal transceiver wiring and multiple RF circuits.
5. The radio frequency module according to claim 2, characterized in that: The radio frequency module also includes: A switch device, the switch device comprising at least two first ports and a second port, the second port being capable of communicating with one of the first ports; wherein at least one of the first ports is electrically connected to the RF circuit, at least one of the first ports not electrically connected to the RF circuit is electrically connected to the second RF socket, and the second port is electrically connected to the RF signal transceiver wiring.
6. The radio frequency module according to claim 5, characterized in that: The number of the radio frequency circuits is N, where N is a positive integer; The number of the first ports is M, where M is a positive integer greater than N; wherein N of the M first ports are electrically connected to the N RF circuits respectively; and among the M first ports, one of the first ports other than the N first ports electrically connected to the N RF circuits is electrically connected to the second RF socket.
7. The radio frequency module according to claim 5, characterized in that: The switch device is a single-pole multi-throw switch; or, the switch device is a coupler.
8. The radio frequency module according to any one of claims 1 to 7, characterized in that: The first electrical path includes a resistive element connected in series between the RF circuit and the RF antenna.
9. The radio frequency module according to any one of claims 1 to 7, characterized in that: The radio frequency module also includes: A first connector, the first connector is arranged on the second surface, and the first connector is electrically connected to the radio frequency circuit; An adapter board is provided with a second connector and a third radio frequency socket, and the second connector can be connected to the first connector to connect the radio frequency circuit to the third radio frequency socket.
10. An electronic device, characterized in that: The electronic device comprises: A radio frequency module for an electronic device as claimed in any one of claims 1 to 9.