Abstract: Systems and methods provide for determining a distance between a signpost and a tag and for locating a tag using multiple signposts. The system uses a signal received at a tag from a signpost, and from them measures the signal strength of the signal with respect to one or more antennas on the tag. The system calculates an RSSI using the measured signal strength, from which a distance can be determined between the signpost and the tag. The system also uses signals received from multiple signposts, to measure multiple signal strengths, resulting in multiple distance determinations corresponding to the various signposts, thereby establishing a location for the tag.

Abstract: Systems and methods provide for determining a distance between a signpost and a tag and for locating a tag using multiple signposts. The system uses a signal received at a tag from a signpost, and from them measures the signal strength of the signal with respect to one or more antennas on the tag. The system calculates an RSSI using the measured signal strength, from which a distance can be determined between the signpost and the tag. The system also uses signals received from multiple signposts, to measure multiple signal strengths, resulting in multiple distance determinations corresponding to the various signposts, thereby establishing a location for the tag.

Abstract: A phase locked loop circuit for use in an automatic frequency synthesizing system. The system includes a programmer circuit which is responsive to a channel number input signal and generates a first digital control signal which is representative of the selected channel number and a second digital control signal which is representative of a predetermined group of channel numbers. A programmable divider is controlled by the programming circuit and generates a digital output signal which causes the phase locked loop circuit to generate a desired system output frequency corresponding to the selected channel number input signal. The phase locked loop circuit includes automatic fine tuning and manual fine tuning features.