EP0441031A2
Expired / Lapsed
EP
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High speed system for reading and writing data from and into remote tags
Assignee: Amtech Systems Inc
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Filing: 1990-11-05
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Granted: —
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Expires: 2010-11-05
Abstract
Abstract The subject invention relates to a system for reading from and for writing data into electronic tags which may be associated with objects which are moving with respect to an interrogator, or may be located in fixed positions in the path of a moving interrogator. The interrogator, which is stationary if the tag is moving, sends a continuous RF signal to the remote tag. The tag backscatter-modulates the received RF signal with data temporarily or permanently stored in the tag, including, for example, data associated with the object to which the tag is attached, for example, its identity or contents. The system of this invention uses a very efficient encoding technique for the data which is backscatter-modulated by the tag and received by the interrogator. The backscatter-modulated signals are made up of signals of first and second frequencies f₁ and 2f₁, respectively, where the second frequency 2f₁ is twice the first frequency f₁, and where one of the two binary bits ONE and ZERO is represented by one-half period of a signal of the first frequency followed by one period of the second frequency, and the other of the two binary bits is represented by one period of a signal of the second frequency followed by one-half period of a signal of the first frequency. The signals also contain FRAME MARKERS made up of five periods of frequency 2f₁ followed by one-half period of frequency f₁. The WRITE-by-RF signals sent to the tag by the interrogator are made up of pulses of three different frequencies, one being frequency f₂, the next 2f₂ and the third 4f₂. Either a ZERO or a ONE can be one period of pulses of either 2f₂ or 4f₂ with the other bit being the other frequency, and with the FRAME MARKER being one period of frequency f₂. The MODE signal is four periods of frequency f₂.
Inventors
- 👤 Peter L. Hendrick
- 👤 Donald F. Speirs
- 👤 Michael A. Wolf
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:54
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/59; B; B61; B61L; B61L25/00; B61L25/02; B61L25/04; B61L25/048; G; G01; G01S; G01S13/00; G01S13/74; G01S13/82; G01S13/825; G06; G06F; G06F17/00; G06F17/40; G06K; G06K7/00; G06K7/0008
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
239 words
A system for reading data from and for writing data into a tag associated with a remote object, which may be in motion relative to the interrogator, comprising: an interrogator for sending a modulated RF signal to said tag, said signal including data intended to be received and stored by said tag; at least one tag capable, upon receipt of a continuous RF signal, of backscatter-modulating said RF signal and returning a backscatter-modulated signal to said interrogator, said backscatter-modulated signal being modulated with data relating to said remote object, said backscatter-modulated signal being made up of signals of first and second frequencies f₁ and 2f₁, respectively, where the second frequency 2f₁ is twice the first frequency f₁, 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; said interrogator having the capability (1) to obtain information from said tag from said returned backscatter-modulated signal made up of the said signals of first and second frequencies and (2) to transmit data to said tag, whereby data may be READ from and transmitted to and stored by said tag very rapidly while said tag or said interrogator is moving.
Claim 2
Dependent Claim
52 words
The system for reading from and for writing data into a tag of claim 1 further characterized by said backscatter-modulated signal always having a level transition from a high level to a low level or from a low level to a high level between periods of signals of frequency f₁ and 2f₁.
Claim 3
Dependent Claim
44 words
The system for reading from and for writing data into a tag of claim 1 further characterized by said backscatter-modulated signals being capable of designating binary ONES and binary ZEROS when said signals are received in their normal or inverted form by the interrogator.
Claim 4
Dependent Claim
59 words
The system for reading from and for writing data into a tag of claim 3 further characterized by said backscatter-modulated signal having each portion thereof representing a single binary bit being inverted from the predecessor portion thereof signal representing the preceding binary bit, whereby the d.c. component of the signal representing a sequence of two binary bits is zero.
Claim 5
Dependent Claim
41 words
The system for reading from and for writing data into a tag of claim 1 further characterized by said backscatter-modulated signal including a FRAME MARKER signal which contains five periods of signal frequency 2f₁ followed by one-half period of frequency f₁.
Claim 6
Dependent Claim
46 words
The system for reading from and for writing data into a tag of claim 5 further characterized by said FRAME MARKER signal being either the said five periods of signal frequency 2f₁ followed by one-half period of frequency f₁, or the inverted form of that signal.
Claim 7
Dependent Claim
32 words
The system for reading from and for writing data into a tag of claim 5 further characterized by said FRAME MARKER being inverted relative to the binary bits preceding and following it.
Claim 8
Dependent Claim
45 words
The system for reading from and for writing data into a tag of claim 5 further characterized by said FRAME MARKER, in conjunction with an odd number of binary bits preceding or following it, having a d.c. component equal to zero across the entire frame.
Claim 9
Dependent Claim
185 words
A tag adapted to be attached to a remote object, said tag containing data associated with said remote object and being capable of having at least a portion of its data contents varied by the receipt of a modulated RF signal from an interrogator which may be in motion 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 f₁ and 2f₁, respectively, where the second frequency 2f₁ is twice the first frequency f₁, 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.
Claim 10
Dependent Claim
40 words
The tag of claim 9 further characterized by said backscatter-modulated signal always having a level transition from a high level to a low level or from a low level to a high level between periods of frequency f₁ and 2f₁.
Claim 11
Dependent Claim
34 words
The tag of claim 9 further characterized by said backscatter-modulated signal being capable of designating binary ONES or binary ZEROS when said signals are received in their normal or inverted form by the interrogator.
Claim 12
Dependent Claim
48 words
The tag of claim 9 further characterized by said backscatter-modulated signal having each portion thereof representing a single binary bit being inverted from the predecessor portion thereof representing the preceding binary bit, whereby the d.c. component of the signal representing a sequence of two binary bits is zero.
Claim 13
Dependent Claim
32 words
The tag of claim 9 further characterized by said backscatter-modulated signal including a FRAME MARKER signal which contains five periods of signal frequency 2f₁ followed by a one-half period of frequency f₁.
Claim 14
Dependent Claim
37 words
The tag of claim 13 further characterized by said FRAME MARKER signal being either the said five periods of signal frequency 2f₁ followed by a one-half period of frequency f₁, or the inverted form of that signal.
Claim 15
Dependent Claim
32 words
The system for reading from and for writing data into a tag of claim 13 further characterized by said FRAME MARKER being inverted relative to the binary bits preceding and following it.
Claim 16
Dependent Claim
45 words
The system for reading from and for writing data into a tag of claim 13 further characterized by said FRAME MARKER, in conjunction with an odd number of binary bits preceding or following it, having a d.c. component equal to zero across the entire frame.
Claim 17
Independent Claim
189 words
A system for reading data from and for writing data into a tag associated with a remote object, which may be in motion relative to the interrogator, comprising: an interrogator for sending a modulated RF WRITE signal to said tag, said WRITE signal including data intended 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 2f₂ and the other binary digit represented by a signal having a frequency 4f₂; at least one tag capable, upon receipt of a continuous RF signal, of backscatter-modulating said continuous RF signal and returning 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 having the capability (1) to obtain information from said tag from said returned backscatter-modulated signal made up of the said signals of first and second frequencies and (2) to transmit data to said tag, whereby data may be READ from and transmitted to and stored by said tag very rapidly while said tag or said interrogator is moving.
Claim 18
Dependent Claim
33 words
The system for reading data from and for writing data into a tag of claim 17 further characterized by said WRITE signals representing each of the two binary bits being one period long.
Claim 19
Dependent Claim
34 words
The system for reading data from and for writing data into a tag of claim 18 further characterized by said period being one-half period of RF off followed by one-half period of RF on.
Claim 20
Dependent Claim
37 words
The system for reading data from and for writing data into a tag of claim 17 further characterized by said RF WRITE signal including a FRAME MARKER which contains one period of a signal of frequency f₂.
Claim 21
Dependent Claim
34 words
The system for reading data from and for writing data into a tag of claim 20 further characterized by said period being one-half period of RF off followed by one-half period of RF on.
Claim 22
Dependent Claim
37 words
The system for reading data from and for writing data into a tag of claim 17 further characterized by said RF WRITE signal including a MODE signal which contains four periods of a signal of frequency f₂.
Claim 23
Dependent Claim
35 words
The system for reading data from and for writing data into a tag of claim 22 further characterized by said four periods are four half-periods of RF off with four intervening half-periods of RF on.
Claim 24
Dependent Claim
109 words
The system for reading data from and for writing data into a tag of claim 17 further characterized by said backscatter-modulated signal being made up of signals of first and second frequencies f₁ and 2f₁, respectively, where the second frequency 2f₁ is twice the first frequency f₁, 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.
Claim 25
Dependent Claim
33 words
The system for reading data from and for writing data into a tag of claim 24 further characterized by the frequency f₂ being less than or equal to one-half of the frequency f₁.
References Cited (Backward Citations)
No citation records indexed.
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