Abstract: In one embodiment, a stylus includes one or more electrodes included in a tip, and a computer-readable non-transitory storage medium embodying logic that is configured when executed to receive, by the one or more electrodes and an analog front end, signals transmitted from a touch sensor coupled to a touch-sensor controller, and convert the signals into sequences of digital signals. The logic is further configured when executed to feed the sequences of digital signals received in different periods into a memory; correlate each of the sequences of digital signals with a digital data defined by a wide-band code to generate multiple correlations; and transmit a transmission signal to the touch-sensor controller according to a synchronization timing determined based at least in part on one or more of the multiple correlations.

Abstract: In one embodiment, a stylus includes one or more electrodes included in a tip, and a computer-readable non-transitory storage medium embodying logic that is configured when executed to receive, by the one or more electrodes and an analog front end, signals transmitted from a touch sensor coupled to a touch-sensor controller, and convert the signals into sequences of digital signals. The logic is further configured when executed to feed the sequences of digital signals received in different periods into a memory; correlate each of the sequences of digital signals with a digital data defined by a wide-band code to generate multiple correlations; and transmit a transmission signal to the touch-sensor controller according to a synchronization timing determined based at least in part on one or more of the multiple correlations.

Abstract: In one embodiment, a stylus includes one or more electrodes included in a tip, and a computer-readable non-transitory storage medium embodying logic that is configured when executed to receive, by the one or more electrodes and an analog front end, signals transmitted from a touch sensor coupled to a touch-sensor controller, and convert the signals into sequences of digital signals. The logic is further configured when executed to feed the sequences of digital signals received in different periods into a memory; correlate each of the sequences of digital signals with a digital data defined by a wide-band code to generate multiple correlations; and transmit a transmission signal to the touch-sensor controller according to a synchronization timing determined based at least in part on one or more of the multiple correlations.

Abstract: In one embodiment, an active stylus includes a receiver and a transmitter configured to receive and transmit signals from and to a device via a touch sensor of the device, wherein the transmitter is integrated with or comprises an adaptive voltage generation circuit including: a boost voltage controller; a comparator; a switch control; and a bleeder circuit. The active stylus further includes a stylus controller configured to: (a) in a first operation state, control the adaptive voltage generation circuit and the transmitter to transmit signals at a second transmit voltage, and (b) in a second operation state different from the first operation state, control the adaptive voltage generation circuit and the transmitter to transmit signals at a first transmit voltage lower than the second transmit voltage.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, an active stylus includes a receiver and a transmitter configured to receive and transmit signals from and to a device via a touch sensor of the device, wherein the transmitter is integrated with or comprises an adaptive voltage generation circuit including: a boost voltage controller; a comparator; a switch control; and a bleeder circuit. The active stylus further includes a stylus controller configured to: (a) in a first operation state, control the adaptive voltage generation circuit and the transmitter to transmit signals at a second transmit voltage, and (b) in a second operation state different from the first operation state, control the adaptive voltage generation circuit and the transmitter to transmit signals at a first transmit voltage lower than the second transmit voltage.

Abstract: In one embodiment, an active stylus includes a transmitter configured to transmit electrical signals to a device through a touch sensor of the device. The active stylus also includes a receiver configured to receive electrical signals from the device through the touch sensor of the device. Furthermore, the active stylus includes a controller configured to determine a strength of an electrical signal received by the receiver from the touch sensor of the device and instruct the transmitter to transmit electrical signals to the device at a voltage based at least on the determined strength of the electrical signal received by the receiver.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, a stylus includes a controller, a delay line, a coefficient line and a computer-readable non-transitory storage medium. The controller is operable to receive a synchronization signal that is transmitted from a computing device and received by the stylus. The delay line is operable to store a first consecutive edges of the synchronization signal. The coefficient line includes a pre-determined coefficient vector.

Abstract: In one embodiment, a stylus includes a controller, a delay line, a coefficient line and a computer-readable non-transitory storage medium. The controller is operable to receive a synchronization signal that is transmitted from a computing device and received by the stylus. The delay line is operable to store a first consecutive edges of the synchronization signal. The coefficient line includes a pre-determined coefficient vector.

Abstract: In one embodiment, an active stylus includes a transmitter configured to transmit electrical signals to a device through a touch sensor of the device. The active stylus also includes a receiver configured to receive electrical signals from the device through the touch sensor of the device. Furthermore, the active stylus includes a controller configured to determine a strength of an electrical signal received by the receiver from the touch sensor of the device and instruct the transmitter to transmit electrical signals to the device at a voltage based at least on the determined strength of the electrical signal received by the receiver.

Abstract: In one embodiment, a computer-readable non-transitory storage medium embodies logic that is configured when executed to determine a first correlation between first consecutive edges of a synchronization signal and a pre-determined coefficient vector. The logic is further configured when executed to determine a second correlation between second consecutive edges of the synchronization signal and the pre-determined coefficient vector and synchronize one or more timings for communication between a stylus and a device based at least in part on the first and second correlations.

Abstract: In one embodiment, an active stylus includes a transmitter configured to transmit electrical signals to a device through a touch sensor of the device. The active stylus also includes a receiver configured to receive electrical signals from the device through the touch sensor of the device. Furthermore, the active stylus includes a controller configured to determine a strength of an electrical signal received by the receiver from the touch sensor of the device and instruct the transmitter to transmit electrical signals to the device at a voltage based at least on the determined strength of the electrical signal received by the receiver.

Abstract: In certain embodiments, a method includes wirelessly receiving, by an electrode of a stylus, a signal sent from a touch sensor of a computing device. The received signal includes a data bit and is based on a predefined code sequence. The method also includes producing, by the electrode of the stylus, a derivative signal from the received signal, the derivative signal corresponding to a derivative with respect to time of the received signal. The method further includes performing, by the stylus, a cross-correlation of the derivative signal and an expected-signal pattern, the expected-signal pattern based on a derivative with respect to time of the predefined code sequence, where the cross-correlation produces a cross-correlation signal including one or more cross-correlation pulses. The method also includes determining, by the stylus, based on the cross-correlation signal, that the received signal is associated with the predefined code sequence.

Abstract: In one embodiment, a method performed by an active stylus includes wirelessly receiving a synchronization signal from a touch controller. The method also includes determining a synchronization parameter of the synchronization signal, the synchronization parameter including an integer part and a fractional part, the integer part representing a positive integer multiple of an active-stylus clock period and the fractional part representing a fractional portion of the active-stylus clock period. The method further includes wirelessly transmitting information for reception by the touch controller, where the information includes a series of data portions, a successive data portion in the series being separated from a preceding data portion by a time interval. The time interval is based at least in part on the active-stylus clock period, the integer part of the synchronization parameter, and an updated fractional error value.

Abstract: In one embodiment, a method performed by an active stylus includes wirelessly receiving a synchronization signal from a touch controller. The method also includes determining a synchronization parameter of the synchronization signal, the synchronization parameter including an integer part and a fractional part, the integer part representing a positive integer multiple of an active-stylus clock period and the fractional part representing a fractional portion of the active-stylus clock period. The method further includes wirelessly transmitting information for reception by the touch controller, where the information includes a series of data portions, a successive data portion in the series being separated from a preceding data portion by a time interval. The time interval is based at least in part on the active-stylus clock period, the integer part of the synchronization parameter, and an updated fractional error value.