Identification system
Patent 5041826 Issued on August 20, 1991. Estimated Expiration Date: 
February 16, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 16, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3109143 3510779 3689885 Data recovery system for use with a high speed serial link between two subsystems in a data processing system Apparatus and method for digital combination of delta modulated data Frequency shift keying system Noise detector and data signal receiver for a frequency modulation system Patent #: 4388730 InventorAssigneeApplicationNo. 481833 filed on 02/16/1990US Classes:340/10.42, Identification only340/825.69, Radio link340/825.75, Permutation375/272, Frequency shift keying455/41.1Near field (i.e., inductive or capacitive coupling)ExaminersPrimary: Weldon, UlyssesAttorney, Agent or FirmInternational ClassH04Q 001/00AbstractA passive integrated transponder (PIT) is attached to or embedded in an item to be identified. It is excited via an inductive coupling from an interrogator. The PIT responds to the interrogator via the inductive coupling with a signal constituting a stream of data unique to the identified item. The signal is in the form of two different frequencies, a shift from one frequency to the second during a bit cell representing a data "one", and a shift from the second frequency to the first frequency representing a data "zero". The responsive signal is then detected and processed for utilization in a data storage or display device. | |
