Method and device for modulating an active load
First Claim
Patent Images
1. A method for sending a data frame by inductive coupling, the method comprising:
- receiving, by inductive coupling at an antenna circuit, an alternating external magnetic field, the antenna circuit being tuned based on a carrier frequency of the alternating external magnetic field;
producing, using the 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 based on 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 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;
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 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.
14 Citations
19 Claims
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1. A method for sending a data frame by inductive coupling, the method comprising:
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receiving, by inductive coupling at an antenna circuit, an alternating external magnetic field, the antenna circuit being tuned based on a carrier frequency of the alternating external magnetic field; producing, using the 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 based on 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 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; 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 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, 6, 7)
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8. A device for sending a data frame, the device comprising:
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an antenna circuit in which an antenna signal is generated based on an alternating external magnetic field; an oscillator circuit responsive to a first periodic signal extracted from the antenna signal, the oscillator circuit being configured to generate a second periodic signal based on the first periodic signal, the oscillator circuit having a synchronous oscillation mode configured to synchronize the second periodic signal based on 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 the second periodic signal to the antenna circuit when the oscillator circuit is placed in a free oscillation mode subsequent to being placed in the synchronous oscillation mode; wherein; the oscillator circuit is placed in the synchronous oscillation mode before applying the second periodic signal to the 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 oscillator circuit being placed in the synchronous oscillation mode and a second occurrence of the oscillator circuit being placed in the synchronous oscillation mode is on a scale of one data bit or less. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification