Method and device for modulating an active load with damping of auto oscillation
First Claim
Patent Images
1. A method for sending a data frame by inductive coupling, the method comprising:
- receiving, at an inductive antenna circuit, an alternating external magnetic field, the inductive antenna circuit being tuned to a carrier frequency of the alternating external magnetic field;
producing, using the inductive antenna circuit, a first periodic signal that is based on the alternating external magnetic field;
producing, by an oscillator circuit, a second periodic signal that is based on the first periodic signal;
performing a first synchronization of the second periodic signal to the first periodic signal by placing the oscillator circuit in a synchronous oscillation mode;
placing the oscillator circuit in a free oscillation mode;
sending a first portion of the data frame by applying the second periodic signal to the inductive antenna circuit, the first portion of the data frame being on a scale of one data bit or less; and
after the sending the first portion of the data frame;
modifying an impedance of the inductive antenna circuit to attenuate an amplitude of an output signal of the inductive antenna circuit;
ceasing to modify the impedance of the inductive antenna circuit, so as to restore the amplitude of the output signal of the inductive antenna circuit; and
performing a second synchronization of the second periodic signal to the first periodic signal by placing the oscillator circuit in the synchronous oscillation mode before applying the second periodic signal to the inductive antenna circuit to send a second portion of the data frame, the second portion of the data frame being on the scale of one data bit or less.
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Abstract
A method for sending data by inductive coupling includes: extracting an antenna signal from an antenna circuit, extracting from the antenna signal a first periodic signal, producing a second periodic signal by way of a synchronous oscillator, placing the oscillator in a free oscillation mode and applying to the antenna circuit the second periodic signal, modifying the impedance of the antenna circuit, restoring the amplitude of the antenna signal, then resynchronizing the oscillator on the first periodic signal.
28 Citations
17 Claims
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1. A method for sending a data frame by inductive coupling, the method comprising:
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receiving, at an inductive antenna circuit, an alternating external magnetic field, the inductive antenna circuit being tuned to a carrier frequency of the alternating external magnetic field; producing, using the inductive antenna circuit, a first periodic signal that is based on the alternating external magnetic field; producing, by an oscillator circuit, a second periodic signal that is based on the first periodic signal; performing a first synchronization of the second periodic signal to the first periodic signal by placing the oscillator circuit in a synchronous oscillation mode; placing the oscillator circuit in a free oscillation mode; sending a first portion of the data frame by applying the second periodic signal to the inductive antenna circuit, the first portion of the data frame being on a scale of one data bit or less; and after the sending the first portion of the data frame; modifying an impedance of the inductive antenna circuit to attenuate an amplitude of an output signal of the inductive antenna circuit; ceasing to modify the impedance of the inductive antenna circuit, so as to restore the amplitude of the output signal of the inductive antenna circuit; and performing a second synchronization of the second periodic signal to the first periodic signal by placing the oscillator circuit in the synchronous oscillation mode before applying the second periodic signal to the inductive antenna circuit to send a second portion of the data frame, the second portion of the data frame being on the scale of one data bit or less. - View Dependent Claims (2, 3, 4, 5)
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6. A device for sending a data frame, the device comprising:
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an inductive antenna circuit in which an antenna signal is generated in the presence of an alternating external magnetic field; a synchronous oscillator circuit responsive to a first periodic signal extracted from the antenna signal, the synchronous oscillator circuit being configured to generate a second periodic signal based on the first periodic signal, the synchronous oscillator circuit having a synchronous oscillation mode configured to synchronize the second periodic signal with the first periodic signal; an active load modulation circuit configured to; generate an active load modulation magnetic field for sending the data frame by inductive coupling; and apply bursts of the second periodic signal to the inductive antenna circuit when the synchronous oscillator circuit is placed in a free oscillation mode subsequent to being placed in the synchronous oscillating mode; a damping circuit coupled to the inductive antenna circuit, the damping circuit being configured to; modify an impedance of the inductive antenna circuit to attenuate an amplitude of the antenna signal; and cease modifying the impedance of the inductive antenna circuit, so as to restore the amplitude of the antenna signal, wherein; the synchronous oscillator circuit is placed in the synchronous oscillation mode before applying additional bursts of the second periodic signal to the inductive antenna circuit during the sending of the data frame, and a portion of the data frame that is sent between a first occurrence of the synchronous oscillator circuit being placed in the synchronous oscillation mode and a second occurrence of the synchronous oscillator circuit being placed in the synchronous oscillation mode is on a scale of one data bit or less. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification