WO2015014727A1

WO2015014727A1 - Data connection in a motor vehicle, and transmitter unit and receiver unit for such a data connection

Info

Publication number: WO2015014727A1
Application number: PCT/EP2014/065985
Authority: WO
Inventors: Erwin Köppendörfer
Original assignee: Leoni Kabel Holding Gmbh
Priority date: 2013-08-01
Filing date: 2014-07-24
Publication date: 2015-02-05
Also published as: DE102013012885A1; DE102013012885B4

Abstract

The data connection in the motor vehicle comprises a transmitter unit (6) and a receiver unit (18) that are connected to one another via a data line for the purpose of symmetric signal transmission of a total of three data signals (S1 – S3). In this case, the data line is in the form of a star-quad (16) having two wire pairs (12, 14), the transmitter unit (6) being designed to feed a first and a second transmission signal (U1, U2) into the first wire pair (12) and to feed a third and a fourth transmission signal (U3, U4) into the second wire pair (14). In addition, the transmitter unit (6) and receiver unit (18) are designed to transmit the third data signal (S3) via the star-quad (16) in the manner of a phantom circuit. The individual data signals (S1 – S3) are binary data signals, in particular, preferably based on NRZ coding.

Description

description

Data connection in a motor vehicle and transmitter unit and receiver unit for such a data connection

The invention relates to a data connection in a motor vehicle and to a transmitter unit and receiver unit for such a data connection.

In a motor vehicle electrical system, the integration of more and more intelligent systems both to increase the security and to increase the comfort in addition to the power supply lines also more and more data lines needed. Since these are often security-relevant signals, a high level of data transmission security must be ensured. Some of the resulting data signals can transmit very large amounts of data. Such data signals are therefore typically designed as high-frequency data signals. For example, such data signals are signals from a camera of a driver assistance system.

For such driver assistance systems, more and more stereo cameras are used for monitoring the traffic situation in order to also enable a "spatial vision" of the vehicle, thereby further increasing the amount of data to be transmitted.

Data lines used in vehicle construction are, for example, from

DE 10 2012 205 645 A1 and DE 10 2008 030 222 A1. For transmitting signals via a data line, a transmitter unit and a receiver unit are furthermore provided there. To improve the data transmission security, that is, the signal integrity, the data line is often designed symmetrically. For this purpose, the data line often comprises two wires, instead of just a single, and is designed for example as a so-called twisted pair line. Due to the transmission of the signal and a suitable complementary to this signal via one wire of the data line, the susceptibility is reduced. At the same time there are generally efforts in vehicle construction to reduce the vehicle weight. However, the integration of more and more intelligent systems leads not least due to the increased cabling effort regularly to an additional cost and weight burden.

Based on this, the present invention seeks to provide a safe and reliable data connection for motor vehicles, which is also suitable for the transmission of high data rates, and which is designed to save weight and cost.

The object is achieved according to the invention by a data connection with the features of claim 1 and by a transmitter unit and receiver unit, designed for such a data connection with the features of claim 10.

The advantages and preferred embodiments cited with regard to the data connection are to be transferred analogously also to the transmitter unit and receiver unit and vice versa.

The data connection is preferably integrated in a motor vehicle and comprises a transmitter unit and a receiver unit, which are connected to one another via a data line for symmetrical signal transmission of a first and second data signal. The data line is designed here as a so-called star quad and has two pairs of wires. The transmitter unit is designed to feed a first and second transmission signal into the first pair of wires and to feed in a third and fourth transmission signal into the second pair of wires. In addition, the transmitter unit and the receiver unit are designed to transmit a third data signal via the four-wire data line in the manner of a phantom circuit.

The principle of phantom switching is basically known and was previously used, for example, in house installation systems with installed telephone lines where only a limited number of wires were available to carry additional signals. Also, the use of the phantom circuit is known to telephone network operators for better utilization of a cable. The basic principle of the phantom circuit is generally that a third data signal is superimposed in a suitable manner to the normal signals and recovered on the receiver side by suitable signal evaluation, for example by summation or subtraction.

A star quad is generally a so-called quad stranding in which the four isolated wires are stranded together. Also, the quad or the so-called quad star is known per se and was formerly also used in particular in areas of the telephone network. For example, a star quad from the field of telecommunication systems for telecommunication networks is disclosed in DE 10 2007 018 585 A1. For safe and reliable data transmission nowadays often symmetrical pairs are used, which are stranded together or parallel to each other. In contrast to this, the star quad thus forms a quadruple compound, in which the two cores of a pair face each other. The stranded composite is preferably surrounded by a shield.

In contrast to symmetrical pairs for each data signal, in the present case a star quad is intentionally used for the data transmission, although initially this is basically only suitable for the transmission of two symmetrical data signals. In a stereo camera of a driver assistance system, however, a third data signal must be transmitted. For motor vehicles - unlike existing domestic installation systems - there is also no problem that only a limited number of wires is available. Because in the production of the motor vehicle, the configuration is fixed and therefore there is basically no retrofitting or upgrading. However, in order nevertheless to keep the wire needs as low as possible, the transmission capability of such a star quad is increased within a motor vehicle by exploiting the principle of the phantom circuit. As a result, despite the integration of additional systems no additional weight is required by additional wires. In order to ensure the required data security during transmission, in particular against the background of a large number of possible interference sources, the data transmission of at least the first two data signals is symmetrical. This is generally understood that a data signal to be transmitted is processed in its original form and as an inverted data signal. Disturbances on the transmission link therefore affect the two transmission signals equally. By forming a difference of the two transmission signals on the receiver side such interference signals are then eliminated again.

The main advantage of the solution proposed here with the application of the phantom circuit to an automotive star quad is that this creates an additional transmission channel within the star quad. Additional signals can therefore be transmitted to this additional transmission channel independently of the other signals.

Conveniently, these are safety-related signals, such as a stop or interrupt signal, which are very time-critical and must be transmitted immediately. In principle, a signal transmission can also be achieved via an already used transmission channel by appropriately modulating the signal. However, this is not allowed for safety-critical applications where immediate transmission is required.

Such a safety-critical signal is in particular a signal of a detection unit of a driver assistance system. This transmits the signal to a control unit if it has detected a safety-critical condition, such as a collision hazard, excessive speed, too close to a different road user or an accident situation, etc. About this time-critical signal is then automatically interfere with driving triggered, for example, an automatic braking or in the event of an accident activating safety measures. In a preferred embodiment, the transmitter unit is designed for processing the first and second transmission signal for the two wires of the first pair of wires, for which purpose the third data signal is added to the first data signal and to its inverted first data signal. In addition, the receiver unit is furthermore designed to form a first sum signal by adding these two transmission signals, whereby the third data signal can be obtained.

For the transmission of the third data signal, therefore, in a simple embodiment, in principle already the first pair of wires is sufficient. In this case, the normal ground connection of the vehicle can be used as potential reference for the third data signal. For this reason, therefore, no additional wire is required in this simplified embodiment. This is already sufficient in particular when the third data signal is only a low-frequency signal with a low data rate and / or, if this is a little safety-critical and hardly interference-prone signal.

Conveniently, to increase the transmission reliability for the third data signal, the transmitter unit is additionally designed for special preparation of the third and fourth transmission signal for feeding into the two wires of the second pair of wires. For this purpose, the third data signal is first inverted and added up as an inverted data signal to the second data signal and to its inverted second data signal.

In sum, this therefore means that the original signal of the third data signal is added to the two signal sequences of the first data signal (original signal and inverted signal) transmitted via the first pair of wires and that the two signal sequences of the second data signal (original signal and inverted signal ) in each case the inverted third data signal is added. In that regard, therefore, all three data signals are transmitted symmetrically, since each of the original signal and the inverted signal are included in the transmitted over the four wires signal sequences. For extracting the third data signal, the receiver unit is designed in an expedient embodiment such that a second sum signal is generated by adding the third and fourth transmission signal and finally the third data signal is obtained by adding the two sum signals. Due to the summation of the transmission signals of the two pairs of wires each of the signal component of the first data signal and the second data signal is eliminated, since these are each included as origin and inverted signal in the respective transmitted signal sequence, so that they cancel each other in the summation. Therefore, the third data signal remains as the first sum signal and the inverted third data signal as the second sum signal. By subtracting the two sum signals, the third data signal is then obtained without interference effects.

In order to achieve the greatest possible transmission reliability, the data signals are basically digital signals and preferably binary data signals. Each of the data signals is expediently coded in the same way, and preferably has a sequence of logical zeros and ones. In particular, the coding is carried out according to the so-called NRZ coding. The data signals are therefore characterized by a discrete sequence of exactly two voltage levels.

In order to generate the transmission signals in a suitable manner, the transmitter unit is designed in a preferred embodiment such that it provides discrete signal levels of 0, +/- 1 and +/- 2. Since the data signals consist of the two signal levels "low" and "high", therefore, the signal level 0 corresponds to the "low" state, the signal level +1 to the "high" state, the state -1 to the inverted "high" signal level The state +2 corresponds to the double "high" signal level, and the state -2 corresponds to the inverted double "high" signal level.

The various data signals are preferably data signals with different data rates and correspondingly also different transmission frequencies. The first two data signals are are preferably high-frequency data signals with high data rates, whereas the third data signal is a low-frequency control signal.

Preferably, the first two data signals are video or image signals of a stereo camera and the third data signal is a control signal assigned to the stereo camera, in particular a safety-critical control signal. In stereo cameras used today takes a first image analysis at least partially within the camera. If the corresponding logic recognizes a dangerous situation, a safety-relevant signal is immediately transmitted as the third data signal to a central control unit in which it is further processed and a suitable measure is initiated.

Conveniently, furthermore, the transmitter unit is connected to such a stereo camera and the receiver unit is furthermore connected to a control unit. The stereo camera and the control unit are each integrated in a motor vehicle. The control unit is preferably a control unit of a driver assistance system, which in particular is also connected to or integrated in a multimedia system.

An embodiment of the invention will be explained in more detail with reference to FIGS. Show here

1 is a highly simplified representation of a data connection in a motor vehicle with a star quad as a data line for signal transmission of three data signals and

Fig. 2 shows an example in a greatly simplified representation of the signal sequences of three

Data signals formed by the transmitter unit transmission signals and the extracted at the receiver side data signals.

The data connection is used to connect a stereo camera 2 with a control unit 4 within a motor vehicle. The stereo camera 2 is either a part of the stereo camera 2 or as a separate unit associated with a transmitter unit 6, which at least three signal inputs E1 - E3 for three from the stereo camera 2 output data signals S1 - S3 has. On the output side, the transmitter unit has two connection pairs 8, 10 with connections 8a, 8b and 10a, 1ob. At each of the terminal pairs 8,10 a pair of wires 12,14 a star quad 1 6 is connected. The pairs of wires 12,14 each have insulated wires 12a, 12b and 14a, 14b. The individual wires 12a, 12b, 14a, 14b are stranded together according to a quad stranding. This stranded composite is preferably surrounded by a shield. The star quad 1 6 can basically be part of a complex cable with other wires or even form the cable.

At the receiver end, the data connection furthermore comprises a receiver unit 18 which, in turn symmetrically to the transmitter unit 6, again has two terminal pairs 8, 10, to which the two pairs of wires 12, 14 are connected. On the output side, the receiver unit 18 has three signal outputs A1-A3, which are each connected to the control unit 4. The receiver unit 18 is optionally an integral part of the control unit 4 or formed as a separate unit.

Both in the transmitter unit 6 and in the receiver unit 18, a signal conditioning unit 20 is integrated, which is designed in particular as a computer chip. Therefore, an electronic processing circuit is suitably integrated in this chip. The signal conditioning unit 20 of the transmitter unit 6 has an inversion module 20a and an adder unit 20b. The inversion module 20a serves to generate an inverted data signal S1 ^" , S2 ^" , S3 ^" to each of the data signals S1, S2, S3 applied to a respective signal input E1-E3. The adder unit 20b serves to add in each case two signal sequences, the addition signals to The transmission signals U1 and U2 are thereby fed into the first pair of wires 12 and the transmission signals U3, U4 into the second pair of wires 14. The transmission signals U1 and U2 are fed into the first quadrant 12 and the transmission signals U3, U4 four transmission signals U1 - U4 are formed as follows: U1 = S1 + S3

U2 = S1 ^" + S3

U3 = S2 + S3 ^"

U4 = S2 ^" + S3 ^"

The receiver unit 18 extracts again from these transmission signals U1-U4 the data signals S1-S3, or in each case multiples thereof. The data signals S1 - S3 are therefore simultaneously amplified.

For extracting the data signals S1 to S3 from the transmission signals

U1 - U4 forms the receiver unit 18 by adding or subtracting the

Data signals S1-S3 as follows:

For extracting the first data signal S1, the difference between the two transmission signals U1 and U2 is formed:

U1 - U2 = 2S1

The difference formation eliminates the signal component of the third data signal S3. Due to the inverted first data signal S1 ^" results in this difference formation twice the first data signal S1.

Similarly, to extract the second data signal S2, the difference between the transmission signals U3 and U4 is formed:

U3 - U4 = 2S2

For extracting the third data signal, first a first sum signal SU1 is formed by adding the two transmission signals U1 and U2. The addition eliminates the first data signal S1 and the inverted first data signal S1 ^" and, in the case of a ground potential reference, the third data signal S3 is obtained. SU1 = U1 + U2

In order to also obtain the third data signal S3 free from interfering signals, the difference between the third data signal and the third data signal S3 ^" inverted thereto is formed similarly to the first two data signals S1, S3 fourth transmission signal U3, U4 formed.

SU2 = U3 + U4 = 2S3 ^"

For extracting the third data signal S3, the difference between the two sum signals SU1 and SU2 is finally formed:

SU1 - SU2 = 2S3 - 2S3 ^" = 4S3

Based on the signal sequences shown in FIG. 2, the individual steps described here in the transmitter unit 6 and receiver unit 18 are shown again:

In the left half of the picture, first the data signals S1 - S3 and their inverted data signals S1 ^" - S3 ^" are shown. It can be seen here that these data signals S1-S3 are in each case binary data signals with the signal levels 0 and 1 (signal level 0 = low, signal level 1 = high).

In the left center, the signal sequences of the transmission signals U1-U4 fed by the transmitter unit 6 are initially shown, which are, on the one hand, the addition of the third data signal S3 to the first data signal S1 and the inverted first data signal S1, and, on the other hand, the addition of the inverted one third data signal S3 ^" with the second data signal S2 and the second inverted data signal S2 ^" results. The signal sequences shown in the middle therefore form the transmission signals U1 - U4. They are also designed as digital signals, but now with signal levels of 0, +/- 1, +/- 2.

The right-hand half then finally shows the extraction process for extracting the data signals S1-S3 in the receiver unit 18. As can be seen, the double data signal S1 is obtained by subtracting the two transmission signals U1 and U2, and the first is obtained by adding these two transmission signals U1, U2 Sum signal SU1. Accordingly, by subtracting the transmission signals U3, U4, the double data signal S2 and, by addition, the second sum signal SU2 are obtained. In a last step following this, the quadruple data signal S3 is finally obtained from the two sum signals SU1, SU2 by subtraction. The extracted data signals S1-S3 are then provided at the signal outputs A1-A3 with signal levels -1, 0, +1.

Overall, the data connection described here achieves reliable and reliable data transmission with simultaneously low wiring effort using a star quad 1 6 and utilizing the principle of the phantom circuit within a motor vehicle.

LIST OF REFERENCE NUMBERS

2 stereo camera

4 control unit

6 transmitter unit

8, 10 connection pair

8a, 8b, 10a, 10b connections

12, 14 wire pair

12a, 12b, 14a, 14b veins

16 star quad

18 receiver unit

20 signal conditioning unit

20a inversion module

20b adding unit

22 second signal conditioning unit

22a adding unit

E1 - E3 signal inputs

S1 - S3 data signals

S1 ^"" S3 ^" inverted data signals

A1 - A3 signal outputs

U1 - U4 transmission signals

SU1 first sum signal

SU2 second sum signal

Claims

claims

1 . Data connection in a motor vehicle, comprising a transmitter unit (6) and a receiver unit (18), which are connected to one another via a data line for symmetrical signal transmission of a first data signal (S1) and a second data signal (S2), wherein the data line is a star quad (1 6 ) is provided with two wire pairs (12,14) and the transmitter unit (6) for feeding a first and second transmission signal (U1, U2) in the first pair of wires (12) and for feeding a third and fourth transmission signal (U3, U4) in the second pair of wires (14) is formed, wherein the transmitter unit (6) and receiver unit (18) complementary to the transmission of a third data signal (S3) via the star quad (1 6) are formed in the manner of a phantom circuit.

2. Data connection according to claim 1, wherein the third data signal (S3) is a security-relevant signal, which is to be transmitted without time delay.

3. Data connection according to claim 1 or 2, wherein the transmitter unit (6) is designed such, the third data signal (S3) for processing the first and second transmission signal (U1, U2) to the first data signal (S1) and to its inverted first summing data signal (S1 ^"), and further the receiver unit (18) is adapted to the third data signal (S3) as the first sum signal (SU1) by adding the first and second transmission signal (U1, U2) to be obtained.

4. Data connection according to one of the preceding claims, wherein the transmitter unit (6) is designed such that the third data signal (S3) to invert and as an inverted data signal (S3 ^" ) for processing the third and Fourth transfer signal (U3, U4) to the second data signal (S2) and aufzusummieren on its inverted second data signal (S2 ^" ).

5. Data connection according to claim 4, wherein the receiver unit (18) is designed to generate a second sum signal (SU2) by adding the third and fourth transmission signal (U3, U4) and the third data signal (S3) by adding the first and of the second sum signal (SU1 .SU2).

6. Data connection according to one of the preceding claims, wherein the data signals (S1, S2, S3) are in each case binary data signals.

7. Data connection according to claim 6, wherein the transmitter unit for generating transmission signals (U1, U2, U3, U4) with signal levels of 0, +/- 1 and +/- 2 is formed.

8. Data connection according to one of the preceding claims, in which the first and second data signal (S1, S2) are high-frequency data signals and the third data signal (S3) is a low-frequency control signal.

A data link according to any one of the preceding claims, wherein the first and second data signals (S1, S2) are video signals of a stereo camera (2) and the third data signal (S3) is a control signal of the stereo camera (2).

10. Data connection according to one of the preceding claims, in which the transmitter unit (6) is connected to a stereo camera (2) in a motor vehicle and the receiver unit (18) is connected to a control unit (4).

1 1. Transmitter unit (6) or receiver unit (18), designed for a data connection for the transmission of three data signals (S1, S2, S3) according to one of the preceding claims.

12. transmitter unit (6) according to claim 1 1, the three signal inputs (E1, E2, E3) for the three data signals (S1, S2, S3), a signal conditioning unit (20) and two terminal pairs (8,10) for the two wire pairs (12,14) of the star quad (1 6), wherein the signal conditioning unit (20) is designed such that it is in operation

a data signal (S1, S2, S3) present in each case at a signal input (E1, E2, E3) is inverted,

- adds the third data signal (S3) to the first data signal (S1) as well as to the inverted first data signal (ST) of the first signal input (E1) and provides the transmission signals (U1, U2) obtained thereby at the first connection pair (8),

- to the second data signal (S2) and to the inverted second data signal (S2 ^" ) of the second signal input (E2) the inverted third data signal (S3 ^" ) added and the transmission signals (U3, U4) obtained thereby at the second terminal pair (10 ).

13. receiver unit (18) according to claim 1 1, the three signal outputs

(A1, A2, A3) for the three data signals (S1, S2, S3), a signal conditioning unit (20) and two terminal pairs (8,10) for the two pairs of wires (12,14) of the star quad (1 6), wherein the signal conditioning unit (20) is designed such that it is in operation

for extracting the first data signal (S1), the difference between the transmission signals (U1, U2) applied to the first terminal pair (8),

for extracting the second data signal (S2), the difference between the further transmission signals (U3, U4) applied to the second connection pair (10) is formed,

- Further, a first sum signal (SU1) by adding the transmission signals (U1, U2) of the first terminal pair (10) forms and preferably further comprises a second sum signal (SU2) by addition of the transmission signals (U3, U4) of the second terminal pair (10) and the third data signal (S3) is extracted by adding the two sum signals (SU1, SU2).