Patent ID: 7918190

Claim:
A direction-sensitive electronic animal containment system comprising: a wire loop bounding a selected area, said wire loop defining a safe zone, a correction zone, and an escape zone, said safe zone and said correction zone located within the selected area, said escape zone located outside the selected area; a containment signal generator in communication with said wire loop, said containment signal generator generating a containment signal current in said wire loop, said containment signal current comprising a waveform having a rising slope and a falling slope, the absolute value of said rising slope not equal to the absolute value of said falling slope; a receiver unit determining a direction of approach based on at least one of said rising slope and said falling slope, said receiver unit correcting an animal when the direction of approach indicates the animal is entering said correction zone from said safe zone, said receiver unit allowing the animal to pass without correction when the direction of approach indicates the animal is entering said correction zone from said escape zone, wherein said receiver unit generates a received signal comprising a first pulse having a width and direction corresponding to one of said rising slope and said falling slope and a second pulse having a width and direction corresponding to the other of said rising slope and said falling slope, said direction of approach being determined from the width of said first pulse relative to the width of said second pulse.