Patent ID: 7126475

Claim:
An electronic fence transmitter for self-adjusting the receiving distance comprising: a fence wire buried in a yard along the boundary of a confined area within which a pet may move around freely; a digital-analog (D/A) converter for gradually increasing the voltage applied to the fence wire; a wire voltage amplifier for amplifying voltage outputted from the D/A converter and for applying to the fence wire; a data amplifier for amplifying data signal that is applied to the fence wire from a controller; a power amplifier for power-amplifying a data signal that is outputted from the data amplifier; a voltage detector that is connected in series to the fence wire; a comparator for comparing the detected voltage of the voltage detector with a reference voltage; and a controller by which the D/A converter is controlled according to a signal inputted from the comparator and a voltage applied to the fence wire increasing gradually until a value of the detected voltage is larger than the value of the reference voltage.