Electronic fence transmitter for self-adjusting the receiving distance

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.