Method and circuit intended for high-frequency communication between an interrogator and a smart tag
First Claim
1. A method intended for high-frequency communication between an interrogator and a smart tag,a circuit of said smart tag being galvanically coupled with a voltage source and,according to which method the smart tag observes a first phase (Φ
- i),which is a phase of a voltage induced in a tag'"'"'s antenna by a high-frequency carrier signal generated by the interrogator,characterized inthat the smart tag observes the first phase (Φ
i) in those time intervals located even within a data frame being transmitted,in which time intervals, according to a communication protocol, the smart tag does not transmit packets of high-frequency radio waves,and that the smart tag transmits said high-frequency wave packets,in that it excites its own antenna with a voltage,the phase of which voltage, being a second phase (Φ
t),is set, at the beginning of transmitting each said high-frequency wave packet,each time shifted with respect to said observed first phase (Φ
i)by the same phase angle (Δ
Φ
)being determined by a relation Δ
Φ
=Φ
t−
Φ
i.
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Abstract
When communicating with a traditional interrogator of passive smart tags, an actively transmitting smart tag of the invention, even within a data frame being transmitted, observes a first phase (Φi) being a phase of a voltage induced in a tag'"'"'s antenna by an interrogator'"'"'s high-frequency carrier signal and transmits wave packets in that it excites the antenna with a voltage having a phase (Φt), which is always set at the beginning of transmission of each said wave packet shifted with respect to said first phase (Φi) by the same phase angle (ΔΦ). At ΔΦ=180° an amplitude of voltage across an interrogator'"'"'s antenna, when some of said wave packets influence this antenna, attains the largest attainable interference rise. Miniature actively transmitting smart tags are enabled to wirelessly communicate with said traditional interrogator and a communication range of pocket-sized tags is herewith increased.
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Citations
34 Claims
-
1. A method intended for high-frequency communication between an interrogator and a smart tag,
a circuit of said smart tag being galvanically coupled with a voltage source and, according to which method the smart tag observes a first phase (Φ - i),
which is a phase of a voltage induced in a tag'"'"'s antenna by a high-frequency carrier signal generated by the interrogator, characterized in that the smart tag observes the first phase (Φ
i) in those time intervals located even within a data frame being transmitted,in which time intervals, according to a communication protocol, the smart tag does not transmit packets of high-frequency radio waves, and that the smart tag transmits said high-frequency wave packets, in that it excites its own antenna with a voltage, the phase of which voltage, being a second phase (Φ
t),is set, at the beginning of transmitting each said high-frequency wave packet, each time shifted with respect to said observed first phase (Φ
i)by the same phase angle (Δ
Φ
)being determined by a relation Δ
Φ
=Φ
t−
Φ
i. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
- i),
-
26. A circuit intended for high-frequency communication between
an interrogator and a smart tag a circuit of said smart tag being galvanically coupled with a voltage source and a received signal (rs) induced in a tag'"'"'s antenna (A) being conducted to an input of a variable-gain amplifier (VGA) and an output of said variable-gain amplifier (VGA) being connected through a digitizer (Dig) or directly to a reference input of a phase-matched signal generator (PhMSG; - PhMSG′
) andthe smart tag transmitting high-frequency radio wave packets, which are generated out of a phase-matched signal (ts′
)from an output of the phase-matched signal generator (PhMSG;
PhMSG′
),characterized in that each time at the beginning of transmitting each said wave packet said phase matched signal (ts′
),whose phase is a second phase (Φ
t) increased by 90°
,gets phase-matched in the phase-matched signal generator (PhMSG;
PhMSG′
) with said received signal (rs),which an interrogator'"'"'s high-frequency carrier signal induced in the tag'"'"'s antenna (A) and whose phase as a first phase (Φ
i) is observedin said phase-matched signal generator (PhMSG;
PhMSG′
),so that the second phase (Φ
t) is shifted with respect to said observed first phase (Φ
i)by the same phase angle (Δ
Φ
)being determined by a relation Δ
Φ
=Φ
t−
Φ
i,wherein the second phase (Φ
t) is a phase of a voltage exciting the tag'"'"'s antenna (A)to transmit said high-frequency wave packets, that the output of the phase-matched signal generator (PhMSG;
PhMSG′
)is connected to the tag'"'"'s antenna (A) through an output amplifier (OA) and a capacitor, which output amplifier sets an amplitude of the voltage across the tag'"'"'s antenna (A) as a second amplitude (At) to form said high-frequency wave packets, and that, in order to form said high-frequency wave packets, the phase-matched signal generator (PhMSG;
PhMSG′
) and the output amplifier (OA)are controlled by a transmit-on signal (tos) defining the start and end of tag'"'"'s transmitting. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
- PhMSG′
Specification