Abstract: A cashless business transaction system (e.g., a vending system, a material tracking system, or a highway toll system) incorporates a method and apparatus for transmitting a digital information signal. A signal generator (311) generates a constant frequency signal. A phase modulator (305) varies the instantaneous phase of the constant frequency signal to represent digital information, thereby producing a phase modulated signal (325). A tuned resonant circuit (307) filters and averages the phase modulated signal to produce a simulated FM signal, and transmits the simulated FM signal via its antenna (309). One such business transaction system (e.g., a vending system) incorporates such a transmitter to facilitate transmission of billing information from a device located within a substantially electrically shielded environment.

Abstract: A system apparatus for controlling the whereabouts of an animal includes a receiver/stimulator unit affixed to the animal to selectively administer appropriate aversive stimuli effective to deter the animal from encroachment of boundaries in accordance with predetermined conditions based on radio signals received from at least one battery powered transmitter. The system may receive radio signals intermittently transmitted from the transmitter, the radio signals defining at least one boundary for the animal. The system then selectively administers the appropriate aversive stimuli in response to determining that at least one of the received radio signals satisfies one or more of the predetermined conditions.

Abstract: An apparatus for controlling the whereabouts of an animal is affixed to the animal and selectively administers appropriate aversive stimuli effective to deter the animal from encroachment of boundaries in accordance with predetermined conditions based on the coding and/or timing of radio signals received from at least one transmitter, which may include a wire loop. The apparatus receives radio signals intermittently transmitted from the transmitters, wherein the radio signals define at least one boundary for the animal. The apparatus then selectively administers the appropriate aversive stimuli in response to determining that at least one of the received radio signals satisfies one or more of the predetermined conditions.

Abstract: An RF signaling system and system for controlling the whereabouts of animals utilizing same functions, in a preferred embodiment, by efficiently establishing well-defined electronic boundaries using small, battery powered transmitters transmitting constant envelope RF signals in a near-field regime by repetitively delivering trains of brief, low duty cycle pulses of electrical energy to a resonant circuit which includes an antenna at a low RF carrier frequency corresponding to the resonant frequency of the circuit. During intervals between pulses, the resonant circuit is effectively isolated from the circuit delivering the pulses to minimize loading effects. Further energy efficiency is achieved by interposing inactive interals between at least some successive transmissions of the RF signals represented by the pulse trains. The RF signals emitted by the transmitters are digitally encoded as are those emitted from a wire loop coupled to an optional wire loop unit to define a wire loop boundary.