Method for determining cable termination resistances in communication networks and a corresponding communication network
View Patent ↗The invention relates in general to a method for determining cable termination resistances in communication networks and a corresponding communication network, and is applicable especially to high-speed communication networks in automobiles, which uses dual-wire harnesses like FlexRay e.g. For this purpose a method for determining cable termination resistances in communication networks is proposed, where a termination resistance is assigned to at least a part of the cable ends of the network in accordance with the following steps determining for each cable end the cable length to any other cable end, assigning a weight value to each length where lengths with greater values are combined with higher weights than lengths with smaller values, for all cable ends: summing up the weights assigned to all lengths starting from a specific cable end and assigning this sum to the respective cable end as the weight of this cable end, determining the termination resistance of a specific cable end by multiplying the cable impedance Z with a constant of proportionality and the sum of the weights of all cable ends divided by the weight of the specific cable end.
1. A method for determining cable termination resistances in communication networks, characterized in that a termination resistance is assigned to at least a part of the cable ends of the network comprising:
determining for each cable end the cable length to any other cable end,
assigning a weight value to each length where lengths with greater values are combined with higher weights than lengths with smaller values,
for all cable ends: summing up the weights assigned to all lengths starting from a specific cable end and assigning this sum to the respective cable end as the weight of this cable end,
determining the termination resistance of a specific cable end by multiplying the cable impedance Z with a constant of proportionality and the sum of the weights of all cable ends divided by the weight of the specific cable end.
2. The method in accordance with claim 1 , characterized in that the equivalent resistance resulting from a parallel connection of all termination resistances is equal to half of the cable impedance Z in any case.
3. The method in accordance with claim 1 , characterized in that the weights are successive natural numbers.
4. A communication network characterized in that all cable ends of the network are terminated by termination resistances having values determined by a method in accordance with claim 1 .
5. The method in accordance with claim 1 , characterized in that the weights of the cable ends are successive natural numbers raised to the power of a common exponent.
6. The method in accordance with claim 5 , characterized in that the common exponent lies in the range of (1, 4].
7. The method in accordance with claim 1 , characterized in that a common constant of proportionality is used for all cable ends.
8. The method in accordance with claim 7 , characterized in that the common constant of proportionality is equal to 0.5.
9. A communication network with termination resistances determined by a method in accordance with claim 1 .
10. A communication network in accordance with claim 9 , characterized in that the network is configured as a Controller Area Network (CAN) or as a FlexRay network.