High speed system for reading and writing data from and into remote tags

A tag adapted to be attached to a remote object, said tag containing data associated with said remote object and having at least a portion of its data contents variable by the receipt of a modulated RF signal from an interrogator which is moveable relative to said tag, comprising:

• a writable, non-volatile memory;
• a backscatter-modulating means which, upon receipt of a continuous RF signal, backscatter-modulates said RF signal and returns a backscatter-modulated signal to said interrogator, said backscatter-modulated returned signal being modulated with said data associated with said remote object, said backscatter-modulated signal being made up of signals of first and second frequencies f.sub.1 and 2f.sub.1, respectively, where the second frequency 2f.sub.1 is twice the first frequency f.sub.1, and where one of the two binary bits ONE and ZERO is represented by one-half period of a signal of said first frequency followed by one period of said second frequency, and the other of said two binary bits is represented by one period of a signal of said second frequency followed by one-half period of a signal of said first frequency.

A system for reading data from and for writing data into a tag associated with a remote object, said tag being moveable relative to the interrogator, comprising:

• an interrogator means for sending a modulated RF WRITE signal to said tag, said WRITE signal including data to be received and stored by said tag, said modulated RF WRITE signal having a first binary digit represented by a signal having a frequency 2f.sub.2 and the other binary digit represented by a signal having a frequency 4f.sub.2 ;
• at least one tag means which, upon receipt of a continuous RF signal, backscatter-modulates said continuous RF signal and returns a backscatter-modulated signal to said interrogator made up of two different frequencies, said backscatter-modulated signal being modulated with data relating to said remote object;
• said interrogator means (1) obtaining information from said tag means from said returned backscatter-modulated signal made up of the said signals of first and second frequencies and (2) transmitting data to said tag means, whereby data may be READ from, transmitted to and stored by said tag means very rapidly while said tag means or said interrogator means is moving.