North American Philips Corporation

Radio Systems Corporation

Magnavox Consumer Electronics Company

Allen H Boardman

William R Kaylor

A pet containment system which comprises a transmitter for transmitting a series of electromagnetic signals, and a receiver removably attached to the pet for receiving the series of electromagnetic signals from the transmitter. The transmitter includes means for generating the electromagnetic signals, means for transmitting the electromagnetic signals, and at least one transmitting antenna. The receiver includes at least one receiving antenna, means for comparing the phase of the received electromagnetic signals from the transmitter with a predetermined phase and for producing an electronic indication of a loss of phase, and means for producing a control stimulus to the pet. The present invention also provides a method for producing an area for the containment of a pet.

Wireless pet containment system

A pet containment system uses a transmitter for transmitting a series of electromagnetic signals, and a receiver removably attached to the pet for receiving the series of electromagnetic signals from the transmitter. The transmitter includes means for modulating the electromagnetic signals, means for transmitting the resulting non-random patterns of electromagnetic energy, and at least one transmitting antenna. The receiver includes at least one receiving antenna, means for comparing the signal level of the received electromagnetic signals from said transmitter with a predetermined level and for producing an electronic indication of a loss of signal, means for comparing the phase of the received electromagnetic signals from said transmitter with a reference phase and for producing an electronic indication of a loss of phase, means for producing a warning stimulus to the pet, and means for producing a control stimulus to the pet. The present invention also provides a method for producing an area for the containment of a pet.

Using the interferometer technique, a laser light beam is split into two beams one of which is directed along a first light path having a fixed length and the other is directed along a second light path having a variable length. The length of the second light path is varied by a mirror assembly mounted on a piezoelectric block, the length of which is controlled by a modulation signal corresponding to the desired information signal. When the two light beams are recombined at the ends of the first and the second light paths, the varying of the length of the second light path results in a variable phase of the second light beam with respect to the first light beam that is modulation signal dependent at the precise point of recombination of the first and second light beams. The effect of the variable phase combination of the first and second light beams is a vectorial phase addition, the resultant laser light beam after this vectorial combination being intensity (amplitude) modulated by the modulation signal.

Method and apparatus for amplitude modulation of laser light

A circuit for providing a mirrored version of a preselected transfer function includes a circuit having the preselected transfer function coupled to receive a signal modulated by a signal that is to experience the mirrored transfer function. The modulated signal at the output terminal of this circuit is mixed with a signal at a frequency that is greater than the carrier frequency of the modulated signal. The signal resulting from this mixing operation then is low pass filtered to provide the desired mirrored response.

Reverse Nyquist slope filter

Apparatus is provided for coupling one of two signal sources to the antenna terminals of a television receiver. An antenna switch is provided which includes solid state switching elements which when receiving a biasing voltage connects one of two input ports to an output port for delivering a signal to a television receiver. In the unbiased state, the remaining input port is connected to the television receiver antenna terminals. High isolation is provided to prevent stray radiation from one signal source being received by a second signal source.

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Maryville, TN, United States of America

Allen H Boardman