Abstract: A radio transmitter used to transmit an activation signal for radio tags held by individuals or the like provides multi-dimensional polarization to an activation signal so as to allow more consistent range detection of an individual with a tag having a single axis of sensitivity. Circular or spherical polarization can be obtained using the system which may include an antenna design permitting decoupling of antennas necessary for the polarization, a quadrature locking system simplifying proper phase control of the necessary signals and a system for tuning the same.

Abstract: A radio transmitter used to transmit an activation signal for radio tags held by individuals or the like provides multi-dimensional polarization to an activation signal so as to allow more consistent range detection of an individual with a tag having a single axis of sensitivity. Circular or spherical polarization can be obtained using the system which may include an antenna design permitting decoupling of antennas necessary for the polarization, a quadrature locking system simplifying proper phase control of the necessary signals and a system for tuning the same.

Abstract: A primary device for a synchronous event system. In one construction, the primary device includes a solar panel operable to convert light into electricity; a receiver operable to receive a global positioning system time signal; a processor coupled to the receiver and operable to process the global positioning system time signal to produce a processed time component; an internal clock coupled to the processor and operable to store the processed time component and to increment relative to the processed time component thereafter to produce an internal time; and a transmitter coupled to the processor and operable to transmit the internal time to a secondary device for wireless reception by the secondary device and synchronization of the secondary device relative to the primary device.

Abstract: A primary device for a synchronous event system. In one construction, the primary device includes a solar panel operable to convert light into electricity; a receiver operable to receive a global positioning system time signal; a processor coupled to the receiver and operable to process the global positioning system time signal to produce a processed time component; a internal clock coupled to the processor and operable to store the processed time component and to increment relative to the processed time component thereafter to produce an internal time; and a transmitter coupled to the processor and operable to transmit the internal time to a secondary device for wireless reception by the secondary device and synchronization of the secondary device relative to the primary device.

Abstract: An electronic article surveillance system of type including a transmitter for providing in a preselected area an electromagnetic field periodically swept in frequency over a predetermined range of frequencies for causing tags in the preselected area to generate tag signals containing a frequency within the predetermined range of frequencies and a receiver including a detector for receiving the tag signals and providing output indication of detected tag signals, has a modulator in its transmitter which modulates the electromagnetic field and a modulation responsive circuit in its receiver for synchronizing the detector with the frequency of the electromagnetic field.

Abstract: A periodic pulse discrimination system particularly suitable for use with electronic article surveillance systems is capable of detecting valid tag pulses while discriminating against periodic pulses caused by resonances and interfering carriers as well as random noise. Circuitry that determines the periodicity of a pulse signal and is responsive to amplitude differences between successive detected pulses controls an adaptive threshold and sampling window to discriminate against signals having an incorrect periodicity and an inadequate envelope rise time. A notch circuit notches out pulse trains that have the correct or substantially correct periodicity but persist for a longer time period than the time period required for a tag to pass through the detection zone.

Abstract: A means for scrambling video signals by the application of a periodic scrambling waveform which has the effect of altering the normal amplitude relationship between horizontal sync and the video picture portion of a horizontal line uses the comparison between the brightness level of the video signal during a predetermined time period with a reference as a means for varying the amplitude of the periodic scrambling waveform.