Patent ID: 7489115

Claim:
Method in a low voltage net data transmission system for keeping a load signal voltage constant at a location, in which method a coupling device for making the load signal voltage constant comprises: a signal amplifier, a supply voltage source for the signal amplifier, one of a low pass or band pass filter, a coupling unit for connecting to an electric network, a connecting cable having a length and a series impedance, a measuring and handling unit of transmitted signals for a storage location determination, a process unit including a sample and holding circuit and control circuits to produce a control signal with a signal producer, characterized in that in the method a feedback signal from the location is lead to the measuring and handling unit of the transmitted signals and further to the process unit including the sample and holding circuit and the control circuits, and the control signal of the process unit is further taken to steer the following: the supply voltage source for the signal amplifier, the signal amplifier, the one of the low pass or band pass filter, and the coupling unit for connecting to the electric network, in such a depending way that from one of the load impedance, the series impedance of the connecting cable or the frequency, load signal voltage is kept almost constant.