Stylus to host synchronization
First Claim
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1. A signal processing device configured to be coupled to a sensor array including first electrodes extending in a first direction and second electrodes extending in a second direction different from the first direction, the signal processing device comprising:
- a signal generator configured to generate a first sensor transmission signal and a second sensor transmission signal, wherein a frequency of the first sensor transmission signal is greater than a frequency of the second sensor transmission signal, and the second sensor transmission signal is usable for sensing a passive object on the sensor array; and
a processor coupled to the signal generator and configured to;
transmit the first sensor transmission signal capacitively via the sensor array to an active stylus, wherein the first sensor transmission signal allows the active stylus to determine when to transmit a stylus transmission signal to the sensor array;
determine whether the active stylus is present on the sensor array based on the stylus transmission signal, which is capacitively received by the sensor array in a first time period and is distinguishable from the first sensor transmission signal; and
after determining that the active stylus is present on the sensor array, detect a position of the active stylus on the sensor array based on the stylus transmission signal capacitively received by the sensor array in a second time period subsequent to and different from the first time period.
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Abstract
A system and method for synchronizing a stylus to a capacitive sense array. The system including a capacitive sense array which includes a plurality of electrodes. A synchronization signal is transmitted to the stylus using the plurality of electrodes. The synchronization signal is transmitted to the stylus by capacitively coupling the stylus to the capacitive sense array.
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Citations
17 Claims
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1. A signal processing device configured to be coupled to a sensor array including first electrodes extending in a first direction and second electrodes extending in a second direction different from the first direction, the signal processing device comprising:
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a signal generator configured to generate a first sensor transmission signal and a second sensor transmission signal, wherein a frequency of the first sensor transmission signal is greater than a frequency of the second sensor transmission signal, and the second sensor transmission signal is usable for sensing a passive object on the sensor array; and a processor coupled to the signal generator and configured to; transmit the first sensor transmission signal capacitively via the sensor array to an active stylus, wherein the first sensor transmission signal allows the active stylus to determine when to transmit a stylus transmission signal to the sensor array; determine whether the active stylus is present on the sensor array based on the stylus transmission signal, which is capacitively received by the sensor array in a first time period and is distinguishable from the first sensor transmission signal; and after determining that the active stylus is present on the sensor array, detect a position of the active stylus on the sensor array based on the stylus transmission signal capacitively received by the sensor array in a second time period subsequent to and different from the first time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An active stylus configured to indicate a position on a sensor array including first electrodes extending in a first direction and second electrodes extending in a second direction different from the first direction, the active stylus comprising:
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signal reception circuitry which, in operation, capacitively receives a first sensor transmission signal, from the sensor array and determines when to transmit a stylus transmission signal based on the received first sensor transmission signal; and signal transmission circuitry which, after the signal reception circuitry receives the first sensor transmission signal, transmits the stylus transmission signal that is distinguishable from the first sensor transmission signal, wherein the stylus transmission signal transmitted in a first time period allows the sensor array to detect a presence of the active stylus and the stylus transmission signal transmitted in a second time period subsequent to and different from the first time period allows the sensor array to detect a position of the active stylus, and wherein the sensor array transmits a second sensor transmission signal distinguishable from the first sensor transmission signal, a frequency of the first sensor transmission signal being greater than a frequency of the second sensor transmission signal, via the first electrodes of the sensor array in a third time period, and receives signals indicative of a presence of a passive object via the second electrodes of the sensor array in a fourth time period, wherein the third time period overlaps with the fourth time period. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification