A simple electronic horological device, termed a time cell, is presented with associated methods, systems, and computer program products. A time cell has an insulated, charge storage element that receives an electrostatic charge through its insulating medium, i.e. it is programmed. Over time, the charge storage element then loses the charge through its insulating medium. Given the reduction of the electric potential of the programmed charge storage element at a substantially known discharge rate, and by observing the potential of the programmed charge storage element at a given point in time, an elapsed time period can be determined. Thus, the time cell measures an elapsed time period without a continuous power source. One type of time cell is an analog time cell that may have a form similar to a non-volatile memory cell, particularly a floating gate field effect transistor (FGFET). The time cell may have an expanded floating gate for storing an electrostatic charge. At a given point in time after programming the analog time cell, a sensing operation indirectly observes the retained charge in the floating gate by directly or indirectly observing the threshold voltage of the FGFET. By knowing the operational characteristics of the time cell and its initial programming condition, the observation can be converted into an elapsed time value. A time cell can be designed and/or programmed to select the range of time to be measured.
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is related to the following applications: application Ser. No. 09/703,344, filed Oct. 31, 2000, titled "Batteryless, Oscillatorless, Binary Time Cell Usable as an Horological Device with Associated Programming Methods and Devices"; application Ser. No. 09/703,335, filed Oct. 31, 2000, titled "Batteryless, Oscillatorless, Analog Time Cell Usable as an Horological. Device with Associated Programming Methods and Devices"; application Ser. No. 09/703,340, filed Oct. 31, 2000, titled "Sensing Methods and Devices for a Batteryless, Oscillatorless, Binary Time Cell Usable as an Horological Device".
A nonvolatile semiconductor memory device is characterized by including a memory cell to store data, a first reference cell, a check circuit to check a threshold of the first reference cell, and an erase circuit to erase the data of the memory cell in response to detection by the check circuit that the threshold of the first reference cell is smaller than or substantially equal to a predetermined fixed value.
A radio frequency identification transponder includes a power supply and a dynamic memory array that stores data. When power from the power supply ceases, the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. A radio frequency identification transponder includes a signal processor that extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array.
A radio frequency identification transponder including a power supply and a dynamic memory array which stores data. When power from the power supply ceases the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. Further claimed is a radio frequency identification transponder wherein a signal processor extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array. Further claimed is a system wherein a transmitter provides a plurality of temporally spaced interrogating signals which are received by a receiver which incorporates a signal processor that is able to determine the order in which transponders were first in receipt of the interrogating signal. Further claimed is a baggage handling system wherein a transmitter provides a plurality of temporally spaced interrogating signals into an interrogating space through which a conveyor sequentially progresses baggage, a receiver receives transponder response signals which include baggage identity data, a signal processor then extracts the identity data and determines the order in which the baggage has progressed through the interrogating space.
A radio frequency identification transponder includes a power supply and a dynamic memory array that stores data. When power from the power supply ceases, the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. A radio frequency identification transponder includes a signal processor that extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array.
