Method and device for diagnosing an antenna connection for a motor vehicle

Abstract

Method for diagnosing an antenna connection for a motor vehicle, wherein a current (7) is fed in in order to test a connection between a receiving device (8) and an antenna connection (5), wherein the current (7) is fed in for a maximum of a predetermined time interval, characterized in that a current path, via which the fed-in current (7) flows in the good case, is guided via a short-circuit bridge (3) between two connection pins of the antenna connection (5), and that for the diagnosis it is checked whether the fed-in current (7) is still present after the short-circuit bridge (3).

Description

[0001] The present invention relates to a method and a device for diagnosing or checking an antenna connection for a motor vehicle in order to check a connection between a receiving device and an antenna connection, for example in a motor vehicle.

[0002] According to the state of the art, in integrated window antenna systems, the correct plugging of all plug connections between a receiving device (e.g. radio / navigation device) and a final connection between a window connection wire and an active or passive impedance converter is checked by the receiving device in such a way that an operating current or part of the operating current in the case of an active impedance converter and a diagnostic current in the case of a passive impedance converter is conducted via an antenna cable and via all plug connections. If it is detected that the operating or diagnostic current lies outside a defined range, the receiving device creates an entry in an error memory. In order to also be able to check plug connections which, starting from the receiving device, are located behind the impedance converter, the operating or diagnostic current isDiagnostic current is routed via a short-circuit bridge between two connection pins of a disk connector and only then fed to the impedance converter. Alternatively, a portion of the operating current is routed via a short-circuit bridge between two connection pins of the disk connector and used to turn on a switch that supplies the impedance converter.

[0003] If an antenna disk structure is to be used for several reception services (e.g. TV, radio, navigation, etc.) in a combined impedance converter housing, one or more connections to the antenna disk structure are usually provided for each service. If, with n connection pins of the disk connector, more than (n - 2) pins are used to contact the antenna disk structure, an electrical potential will inevitably be present at at least one antenna of the antenna disk structure during the above-mentioned diagnostic procedure according to the state of the art. If there are other metallic structures in the immediate vicinity of this antenna structure subject to an electrical potential, such asa heating field of a heatable window or antenna structures, at a different electrical potential, a "pitting" (electrical corrosion) occurs on the metallic structures due to the potential difference, particularly when the window structures are dirty or damp.

[0004] DE 199 23 729 A1 relates to a circuit arrangement for testing the functional readiness of radio telephone antennas. The antennas each have a radiator, one end of which protrudes openly into the room. Independent of a signal current, test currents flow to the antennas via antenna cables. A secondary path with an impedance is connected to each radiator in parallel to the RF path to return the separate test current. Voltage evaluators monitor the functional status of the antennas by comparing the test voltages at the antenna terminals caused by the test currents with a target value and generate corresponding indication signals that provide information about the functional status of the antennas.

[0005] The diagnostic circuit according to DE 103 34 061 A1 performs not only a dynamic diagnosis of the antennas and supply lines using an alternating signal, but also a static diagnosis using a direct signal. This not only checks whether a faulty antenna has a short circuit or an open circuit. Advantageously, it can also determine which of the antennas is defective, whether a supply line is defective, and which type of fault is present. Furthermore, the phase difference between the current and voltage at the antennas can be determined, allowing the capacitive and inductive influence of the supply lines to be determined.

[0006] In a diagnostic method for monitoring at least one connector to an antenna according to DE 103 60 209 A1, a diagnostic signal is fed toward the antenna via the antenna signal path. The diagnostic signal bypasses an active circuit in the antenna signal path. If the connector is defective, the diagnostic signal affects the power supply of the active circuit. If the power consumption falls outside a specified range, a fault is signaled.

[0007] Therefore, the object of the present invention is to check an antenna connection in such a way that no damage, for example due to pitting corrosion, can occur.

[0008] According to the invention, this object is achieved by a method for diagnosing an antenna connection for a motor vehicle according to claim 1 and a correspondingly designed device according to claim 6. The dependent claims define preferred and advantageous embodiments of the invention.

[0009] Within the scope of the present invention, a method for diagnosing or testing an antenna connection for a motor vehicle is provided. A current is supplied or a voltage is applied to check whether the electrical connection between a receiving device and an antenna connector is correctly wired (plugged in) or fault-free. This checks whether the electrical connection between the receiving device, an antenna, and an antenna device, such as an impedance converter or an antenna amplifier, is fault-free. The current or voltage is supplied or applied for no longer than a predetermined time interval.

[0010] The predetermined time interval is defined as a time interval that is set prior to diagnosing the antenna connection and is preferably set to 10 ms. Normally, the predetermined time interval is set or determined once and then applies to all subsequent antenna connection diagnostic procedures.

[0011] By applying or supplying the current or voltage for a maximum of this predetermined time interval, the risk of the applied current or voltage causing damage, such as the aforementioned pitting, exists only for this predetermined time interval. By selecting a sufficiently short predetermined time interval, such damage can be virtually eliminated using the inventive method for diagnosing the antenna connection.

[0012] In one embodiment of the invention, a current path or an electrical connection, through which the injected current flows under normal conditions, is routed via a short-circuit bridge between two connection points of the antenna connection. To diagnose the antenna connection, a check is carried out to determine whether the injected current is still present after the short-circuit bridge. An antenna connection is understood to be a connection with multiple electrical connection points or connection pins, with each antenna of an antenna structure, which comprises at least one antenna, being connected to one of these electrical connection points (the 'return conductor' of the respective antenna is usually connected to ground).

[0013] Advantageously, an antenna or an antenna access to which a potential is applied for diagnosing the antenna connection is switched to potential-free after the predetermined time interval.

[0014] By isolating the antenna, i.e. dissipating the potential built up during the antenna connection diagnosis, the probability of damage due to the antenna connection diagnosis is further reduced.

[0015] In a further embodiment of the invention, an operating current for an antenna device (e.g., an impedance converter or an antenna amplifier), which is required to operate an antenna connected via the antenna terminal, is only supplied if the antenna connection check was positive. In other words, the antenna device is only switched on if it has previously been positively verified that the antenna connection is error-free. With a passive impedance converter, a diagnostic voltage (a voltage required to perform diagnostic processes) is only applied, or a diagnostic current (a current required to perform diagnostic processes) is only fed, if the antenna connection check was previously positive.

[0016] By not switching on the antenna device when the antenna connection has a fault, e.g. if any connector of the antenna connection is defective, it is advantageously excluded that damage occurs due to the operation of the antenna device.

[0017] Within the scope of the present invention, a device for diagnosing an antenna connection for a motor vehicle is also provided.

[0018] Since the device according to the invention is essentially designed to carry out the method according to the invention described above, only differences from the method according to the invention will be discussed below.

[0019] In one embodiment of the invention, the device comprises a voltage connection, a switch for supplying current to the antenna connection, which is short-circuited via a short-circuit bridge, and a test device for checking the current flowing back from the short-circuited antenna connection or the potential present at the short-circuited antenna connection. Using the test device, the device checks the current flowing back from the short-circuited antenna connection or the potential present at the short-circuited antenna connection as soon as the voltage connection of the device is supplied with voltage, i.e., the device is switched on accordingly. The device is advantageously designed such that it opens the switch at the latest after the expiration of the predetermined time interval if the test device detects no current or no potential.

[0020] An antenna connector shorted with a jumper is a connector that includes at least two ports or pins. An antenna is connected to one of these ports. The jumper then bridges the first port, connected to the antenna, with the second of these ports. The current is then usually routed via the first port to the antenna connector, which is connected to both the jumper and the antenna. A check is then made to determine whether the current flows back from the second port, i.e., whether the electrical connection from the receiving device to the second port is faultless.

[0021] Instead of the current flowing back from the short-circuited antenna connection, the test device can also test a current flowing via the antenna connection to an antenna and from there to ground or another sink. In a further embodiment according to the invention, the device comprises a further switch in order to supply an operating current via this switch to an antenna device (e.g., to an impedance converter or to an antenna amplifier), which is required to operate an antenna connected via the antenna connection. The device is now designed according to the invention such that it closes the further switch only when the test device has detected the current flowing back from the short-circuited antenna connection.

[0022] This ensures that the antenna device is only switched on after it has been positively verified that the antenna connection is functioning correctly.

[0023] The present invention can be used in particular for diagnosing or testing an antenna connection in a motor vehicle during production or during other quality testing (e.g. during a diagnosis in a workshop), whereby pitting of metallic structures is prevented. Naturally, the present invention is not limited to this preferred area of ​​application, but can also be used to test antenna connections outside of a motor vehicle or, for example, to test antenna connections in ships or aircraft. Furthermore, it is possible to use the present invention to test any electrical connection that is not an antenna connection whenever there is a risk that the current fed in for testing or the voltage applied for testing could be too high in the event of a fault, iethe connection to be checked is defective, will cause a problem or damage if the current or voltage is applied for too long (i.e. longer than the predetermined time interval).

[0024] The present invention is explained in more detail below with reference to the accompanying drawings using preferred embodiments. Fig. Figure 1 schematically shows the interaction between a receiver, an impedance converter and an antenna. Fig. 2a to 2f illustrate the operation of a device according to the invention for diagnosing an antenna connection. Fig. 3a and Fig. 3b represent a device according to the invention, wherein a current in the direction of the antenna is detected. Fig. Figure 4 shows a further embodiment of a device according to the invention in detail.

[0025] In Fig. Figure 1 schematically illustrates how a receiver 8, an impedance converter 2, and an antenna 4 are electrically interconnected. The operating voltage is provided via an inner conductor of an antenna line in the impedance converter and is coupled out of the antenna line in a suitable, generally accepted manner.

[0026] In Fig. 2a shows a circuit comprising a device 1 according to the invention, which in turn includes a first switch 11 and a second switch 12, together with an amplifier 2, an antenna connector or antenna plug 5, a window antenna 4 connected thereto, and a third switch 13. The circuit is shown in Fig. 2a is shown in an original state, with switch 13, which must be closed both to supply power to device 1 and to amplifier 2, open. Antenna connector 5 comprises three ports. A first of these ports is connected to antenna 4 and amplifier 2. A second of these ports is also connected to antenna 4, to first switch 11, and to a short-circuit bridge or diagnostic bridge 3. Finally, a third of these ports is also connected to short-circuit bridge 3, to a test terminal 6 of device 1, and to a resistor to ground.

[0027] In Fig. 2b is now the Fig. The circuit shown in Figure 2a is shown in a state shortly after switching on or shortly after closing the third switch 13. By closing the third switch 13, the device 1 is supplied with voltage and a current 7 is conducted via the third switch 13, the closed first switch 11, and the short-circuit bridge 3 to the test terminal 6, if the corresponding connection or a corresponding current path is not interrupted. In other words, by closing the switch 13, a Fig. 2b left-side connection of the switch 13 is applied to the antenna 4. The device 1 now checks, as soon as it is supplied with a voltage via the switch 13, whether a

[0028] Current 7 is flowing or whether a potential is present at its test terminal 6 which corresponds to the potential of the left-side terminal of the switch 13. If the device 1 detects that a current is flowing via its test terminal 6 or that the potential is present at its test terminal 6 which corresponds to the potential of the left-side terminal of the switch 13, the device 1 detects that a good case exists and in the other case (via its

[0029] If no current flows through test terminal 6 or the potential of the left-side terminal of switch 13 is not present at test terminal 6, an error has occurred.

[0030] In Fig. Figure 2c now shows a situation that occurs when the good case has been detected by the device 1. As soon as the device 1 has detected the good case, it closes the second switch 12, via a signal 22 generated by a holding circuit of the device 1, via which the amplifier 2 is supplied with voltage, i.e., it is switched on.

[0031] In Fig. 2d, on the other hand, shows a situation which occurs when the fault has been detected by the device 1, for example when the antenna connector 5 is not fully inserted. In this case, the second switch 12 is not closed, and the amplifier 2 is therefore not switched on.

[0032] In Fig. 2e shows a situation which, in the best case, occurs shortly after the Fig. 2c is present. In the good case, the device 1 opens the first switch 11 shortly after the second switch 12 closes, using a signal 21 generated by another holding circuit of the device 1. The nominal current now flows in the circuit, since all connections (plug connections) required for operation are OK. Fig. The state shown in 2e is a final state in the good case, which can be left by opening the third switch 13, which corresponds to the original state.

[0033] In Fig. 2f shows a situation which, in the event of an error, occurs shortly after the Fig. 2d. Even in the event of a fault, device 1 opens first switch 11 using signal 21 within 10 ms of closing third switch 13. This dissipates the potential present at antenna 4, preventing, for example, pitting corrosion. No or hardly any current flows because the connections (plug-in connectors) are faulty.

[0034] Of course, the current flow through the antenna connector in the direction of the antenna disk, e.g. towards ground or towards another sink, can also be detected. Such a case is in Fig. 3a, where the test current flows through the antenna disc to ground. In Fig. 3b the detection of the voltage or

[0035] current before the bridge, with the current after the bridge flowing through a resistor to ground. The other behavior of device 1, as shown in the Fig. 2a to 2f and described above, remains unchanged.

[0036] In Fig. 4 shows a further embodiment of a device 30 according to the invention. The device 30 comprises a first resistor 31, a second resistor 32, a third resistor 33, a capacitor 34, a first normally-on FET 35, a second normally-on FET 36, a PMOS transistor 37, and an NMOS transistor 38. A first circuit point 41 is connected to a first input of the first resistor 31, a first input of the first FET 35, and a first input of the third resistor 33. A second circuit point 42 is connected to a first input of the capacitor 34, a first input of the second resistor 32, and a first input of the NMOS transistor 38. A third circuit point 43 is connected to a second input of the first resistor 31, a second input of the capacitor 34, a control input of the first FET 35, and a control input of the second FET 36.A fourth circuit point 44 is connected to a first input of the second FET 36, a second input of the second resistor 32, a first input of the PMOS transistor 37, and a control input of the NMOS transistor 38. A fifth circuit point 45 is connected to a control input of the PMOS transistor 37 and to a second input of the NMOS transistor 38. A second input of the PMOS transistor 37 is connected to a second input of the third resistor 33. A second input of the FET 35 is connected to a second input of the second FET 36 via a short-circuit bridge 3.

[0037] The functioning of the device 30 according to the invention in the good case is as follows: As soon as a voltage, e.g. 12 V, is applied between the first circuit point 41 and the second circuit point 42, the two FETs 35, 36 switch on. As a result, the voltage between the first circuit point 41 and the second circuit point 42 is also present across the second resistor 32, i.e. between the fourth circuit point 44 and the second circuit point 42, provided that the short-circuit bridge 3 is carrying current, which is the case in good circumstances. Due to the voltage between the fourth circuit point 44 and the second circuit point 42, the NMOS transistor 38 is now also switched on, so that the voltage between the first circuit point 41 and the second circuit point 42 of 12 V is now also present approximately between the first circuit point 41 and the fifth circuit point 45, i.e. at the output terminals of the device 30.

[0038] If, for example, an impedance converter or an antenna amplifier is connected to the two output terminals (circuit points 41, 45), it will only be switched on now. Since the potential of the fifth circuit point is lowered by turning on NMOS transistor 38, this also turns on PMOS transistor 37.

[0039] Due to the voltage applied between the first circuit point 41 and the second circuit point 42, the capacitor 34 is charged, so that the potential of the third circuit point 43 slowly rises. As soon as the potential of the third circuit point 43 exceeds a certain threshold, the two FETs 35, 36 are blocked. This lowers the potential of the fourth circuit point 44, so that the NMOS transistor 38 also turns off. However, this does not change the switching state of the PMOS transistor 37, so that the PMOS transistor 37 remains switched on.

[0040] The operation of the device 30 according to the invention in the event of a fault is as follows: Since the short-circuit bridge 3 does not conduct any current in the event of a fault, the potential of the fourth circuit point 44 essentially corresponds to the potential of the second circuit point 42, even if an operating voltage of 12 V is applied between the first circuit point 41 and the second circuit point 42. For this reason, the NMOS transistor 38 is not switched on, so that no operating voltage can be tapped at the output terminals 41, 45. In other words, for example, an impedance converter connected to the output terminals 41, 45 will not be switched on in the event of a fault for this reason.

[0041] The time interval which elapses from the application of the operating voltage to the input terminals 41, 42 until the two FETs 35, 36 are blocked can be precisely determined by appropriate dimensioning of the series circuit consisting of the first resistor 31 and the capacitor 34.

[0042] In general, only one FET could be used instead of the two FETs 35, 36, or in other words, one of the two FETs 35, 36 could be omitted. However, since the potential of the antenna, which is connected to one of the two accesses short-circuited by means of the short-circuit bridge 3, is transferred via the

[0043] respective FET 35, 36 connected to the access, a design with two FET 35, 36 is advantageous, at least as long as it is unknown to which of the two accesses the antenna is connected.

[0044] To the Fig. In the circuit shown in Figure 4, an operating or diagnostic voltage is applied to input terminals 41, 42 by a receiving device (e.g., radio / navigation device). This operating or diagnostic voltage is then only switched to output terminals 41, 45 under normal conditions. If an active impedance converter or an antenna amplifier is connected to output terminals 41, 45, the operating or diagnostic voltage is an operating voltage for operating the active impedance converter or the antenna amplifier. If, however, a passive impedance converter is connected to output terminals 41, 45, the operating or diagnostic voltage is a diagnostic voltage that can be used to initiate diagnostic processes.

[0045] The Fig. The device 30 shown in Figure 4 can, for example, be arranged within an impedance converter.

[0046] The present invention ensures that an electrical potential is present at an antenna structure only for a very short time (significantly less than 0.5 seconds) after the receiving device (e.g., a radio / navigation device) is switched on. During this short time, the correct connection or plugging of the windshield antenna connector can be diagnosed. After this diagnostic time, the corresponding antenna structure is switched to a potential-free state. The operating current within the impedance converter or antenna amplifier is monitored by the receiving device throughout its entire operating time. Without a correct connection or plugging of the windshield connector, the impedance converter and thus the operating / diagnostic current are not switched on, as described above.

Claims

[1] Method for diagnosing an antenna connection for a motor vehicle, wherein a current (7) is fed in to test a connection between a receiving device (8) and an antenna connection (5), wherein the current (7) is fed in for a predetermined time interval at the most, characterized by that a current path, over which the fed-in current (7) flows in the good case, is led via a short-circuit bridge (3) between two connection pins of the antenna connection (5), and that for diagnosis purposes it is checked whether the fed-in current (7) is still present after the short-circuit bridge (3). [2] Method according to claim 1, characterized by that an antenna (4) which is connected to the receiving device (8) via the antenna connection (5) is switched to potential-free after the predetermined time interval. [3] Method according to one of the preceding claims, characterized bythat an operating current of an antenna device (2), which is required to operate an antenna (4) connected via the antenna connection (5), is only supplied if the test of the connection was positive. [4] Method according to one of the preceding claims, characterized by that the predetermined time interval is 10 ms. [5] Device for diagnosing an antenna connection for a motor vehicle, wherein the device (1, 11; 1, 11, 12; 30) is designed such that the device (1, 11; 1, 11, 12; 30) feeds a current (7) in order to test a connection between a receiving device (8) and an antenna connection (5), wherein the device (1, 11; 1, 11, 12; 30) is additionally designed such that the device (1, 11; 1, 11, 12; 30) feeds the current for at most a predetermined time interval, characterized bythat a current path, over which the fed-in current (7) flows in the good case, is led via a short-circuit bridge (3) between two connection pins of the antenna connection (5), and that for diagnosis purposes it is checked whether the fed-in current (7) is still present after the short-circuit bridge (3). [6] Device according to claim 5, characterized bythat the device (1, 11; 1, 11, 12; 30) comprises a voltage connection (6; 41, 42), a switch (11; 35, 36) for supplying the current (7) to the antenna connection (5), which is short-circuited via a short-circuit bridge (3), and a test device for checking the current (7) flowing back from the short-circuited antenna connection (5) or a voltage present between the short-circuited antenna connection (5) and ground, and that the device (1, 11; 1, 11, 12; 30) is designed such that the device (1, 11; 1, 11, 12; 30) checks the current (7) flowing back from the short-circuited antenna connection (5) or the voltage between the short-circuited antenna connection (5) and ground by means of the test device as soon as the voltage connection is supplied with voltage, and that the device (1, 11; 1, 11, 12; 30) controls the switch (11;35, 36) opens within the predetermined time interval if the test device does not detect any current (7) or voltage; [7] Device according to claim 5, characterized by that the device (1, 11; 1, 11, 12; 30) comprises a terminal (6; 41, 42), a switch (11; 35, 36) for supplying the current (7) to the antenna terminal (5), which is connected to ground or another sink via the antenna (4), and a test device for checking the current (7) flowing to the antenna, and that the device (1, 11; 1, 11, 12; 30) is designed such that the device (1, 11; 1, 11, 12; 30) checks the current (7) flowing to the antenna terminal (5) by means of the test device as soon as the terminal is supplied with voltage, and that the device (1, 11; 1, 11, 12; 30) switches the switch (11; 35, 36) within of the predetermined time interval when the test device does not detect any current (7). [8] Device according to claim 6 or 7, characterized by that the device (1, 11, 12; 30) comprises a further switch (12; 37, 38) in order to supply an operating current to an antenna device (2) which is required for operating an antenna (4) connected via the antenna connection (5), and that the device (1, 11, 12; 30) is designed in such a way that the device (1, 11, 12; 30) only closes the further switch (12; 37, 38) when the test device has detected the current (7) or the voltage. [9] Device according to one of claims 5-8, characterized by that the predetermined time interval is 10 ms. [10] Device according to one of claims 5-9, characterized by that the device (30) comprises a first resistor (31), a second resistor (32), a third resistor, a capacitor (34), a first transistor (35), a second transistor (36), a P-type transistor (37) and an N-type transistor (38), that a first circuit point (41) is connected to a first input of the first resistor (31), to a first input of the first transistor (31) and via the third resistor (33) to a first input of the P-conducting transistor (33), that a second circuit point (42) is connected to a first input of the capacitor (34), to a first input of the second resistor (32) and to a first input of the N-conducting transistor (38), that a third circuit point (43) is connected to a second input of the first resistor (31), to a second input of the capacitor (34) and to a control input of the first transistor (35) and to a control input of the second transistor (36), that a second input of the first transistor (35) is connected to a first input of the second transistor (36) via the short-circuited antenna terminal (5), that a fourth circuit point (44) is connected to a second input of the second resistor (32), a second input of the second transistor (36), a second input of the P-conducting transistor (37) and a control input of the N-conducting transistor (38), and that a fifth circuit point (45) is connected to a control input of the P-conducting transistor (37) and a second input of the N-conducting transistor (38). [11] Device according to claim 10, characterized by that the device (30) is designed such that the voltage connection is formed by the first circuit point (41) and the second circuit point (42), and that an operating voltage for an antenna device (2) can be tapped between the first and the fifth circuit point. [12] Device according to one of claims 5-11, characterized bythat the device (1, 11; 1, 11, 12; 30) is designed to carry out the method according to one of claims 1-6.

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