Transponder having high character capacity

Claim 2

A passive transponder for producing a coded signal in response to the reception of an interrogating signal, comprising: sensing means for developing a voltage in response to the reception of an interrogating signal; pulse shaping means coupled to said sensing means for producing a train of pulses; first encoder means coupled to said pulse shaping means and having a plurality of n output terminals, said encoder means becoming operative in response to said train of pulses for consecutively energizing at a frequency f each of said output terminals in synchronism with the pulses of said train of pulses; second encoder means coupled to said first encoder means and having a plurality of output terminals, said second encoder means becoming operative in response to pulses produced by said first encoder means at a frequency of f/n for consecutively energizing ones of said output terminals in synchronism with the pulses received from said first encoder means; a plurality of signal utilization means; circuit means for coupling ones of said output terminals of said second encoder means to ones of said signal utilization means for sequentially enabling said signal utilization means; second circuit means coupling predetermined ones of said output terminals of said first encoder means to ones of said signal utilization means; and transmitter means coupled to said signal utilization means for outputting radio-frequency signals modulated to reflect the operation of said signal utilization means.

Claim 3

The invention defined in claim 1, wherein said first and said second encoder means comprise monolithic integrated circuits.

Claim 4

The invention defined in claim 2, wherein said second circuit means comprise a plurality of diodes and conductive leads associated therewith, each of said leads traversing a plurality of said output terminals of said first encoder means to form a matrix, predetermined ones of the intersections of said circuit means and said output terminals being conductively connected.

Claim 5

The invention defined in claim 3, wherein said signal utilization means comprise a plurality of NAND gates.

Claim 6

A passive transponder for producing a first, high-frequency signal for identifying the transponder in response to the reception thereby of a second, lower frequency signal, comprising: antenna means for receiving the lower-frequency signal and sustaining a voltage thereacross in the presence of such signal; rectifier means coupled to said antenna for developing a DC voltage; pulse shaping means coupled to said antenna and responsive to the fluctuation of the voltage arising thereacross for producing a continuous train of pulses at a frequency f in response to the presence of the interrogating signal; first encoder means coupled to said pulse shaping means and having a plurality of n output terminals, each of said output terminals sequentially producing an output pulse upon the application of said train of pulses to said first encoder means; a plurality of signal utilization means; a first set of conductors extending from each of the output terminals of said first encoder means; a second set of conductors overlapping said first set of conductors to form a plurality of intersections, predetermined ones of said intersections constituting electrical connections between an output terminal conductor and a second conductor; unidirectional conducting means coupling ones of said conductive intersection to input terminals of said signal utilization means; second encoder means having an input terminal coupled to said first encoder means for reception of pulses produced by said first encoder means at a frequency of f/n for consecutively energizing ones of said output terminals in synchronism with the pulses received from said first encoder means; circuit means coupling ones of said output terminals of said second encoder means to ones of said signal utilization means for sequentially energizing said signal utilization means in the presence of a pulse received from said first encoder means; and transmitter means coupled to said signal utilization means for outputting radio-frequency signals modulated in response to pulses received from said signal utilization means.

Claim 7

A passive transponder for producing a first, high-frequency signal for identifying the transponder in response to the reception thereby of a second, lower frequency signal, comprising: antenna means for receiving the lower-frequency signal and sustaining a voltage thereacross in the presence of such signal; rectifier means coupled to said antenna for developing a DC voltage; pulse shaping means coupled to said antenna and responsive to the fluctuation of the voltage arising thereacross for producing a continuous train of pulses at a frequency f in response to the presence of the interrogating signal; first encoder means coupled to said pulse shaping means and having a plurality of n output terminals, each of said output terminals sequentially producing an output pulse upon the application of said train of pulses to said first encoder means; a plurality of signal utilization means; a first set of conductors extending from each of the output terminals of said first encoder means; a second set of conductors overlapping said first set of conductors to form a plurality of intersections, predetermined ones of said intersections constituting electrical connections between an output terminal conductor and a second conductor; unidirectional conducting means coupling ones of said conductive intersection to input terminals of said signal utilization means; second encoder means having an input terminal coupled to said first encoder means for reception of pulses produced by said first encoder means at a frequency of f/n for consecutively energizing ones of said output terminals in synchronism with the pulses received from said first encoder means; circuit means coupling ones of said output terminals of said second encoder means to ones of said signal utilization means for sequentially energizing said signal utilization means in the presence of a pulse received from said first encoder means; and transmitter means coupled to said signal utilization means for outputting radio-frequency signals modulated in response to pulses received from said signal utilization means.

Claim 8

The invention defined in claim 5, further including voltage regulation means coupled to said rectifying means for providing a supply voltage of a predetermined value.

Claim 9

The invention defined in claim 6, wherein said pulse shaping means comprises bistable means for producing discrete pulses of a predetermined amplitude.

Claim 10

The invention defined in claim 7, wherein said first and said second encoder means comprise monolithic integrated circuits.

Claim 11

The invention defined in claim 8, wherein said signal utilization means comprise NAND gates.

Claim 12

The invention defined in claim 9, wherein signals supplied said transmitter by said signal utilization means serve to modulate the frequency of the radio-frequency signal outputted by said transistor means.

Claim 13

The invention defined in claim 10, wherein said first, lower frequency signal occurs at substantially 10KHz, and said higher-frequency signal occurs at substantially 420KHz.