Abstract: A method for sampling a signal can accurately cancel a noise signal. The method is performed by a capacitive transimpedance amplifying device that can be applied to a photoplethysmography front-end receiver. The method includes sampling a detection signal and its inversion several times in specific order in a sampling period to obtain a target signal without a noise signal. Specifically, the method includes: sampling the detection signal during a first time slot and a fourth time slot; and sampling the inversion of the detection signal during a second time slot and a third time slot, wherein the first, second, third, and fourth time slots are in sequence and included in the sampling period, the detection signal includes the target signal and the noise signal during the first and fourth time slots, and the detection signal only includes the noise signal during the second and third time slots.

Abstract: An ambient light cancellation circuit functions as a Kth-order filter to filter out an ambient light signal of the detection signal, wherein the K is not fewer than two. The circuit includes a capacitive transimpedance amplifying circuit including an amplifier, a capacitor circuit, and a switch circuit. The capacitor circuit includes one or more capacitive paths coupled in parallel. The switch circuit couples the amplifier with the capacitor circuit in a non-cross manner or a cross manner. The non-cross manner is applied N times to let the capacitor circuit sample the detection signal N times while the detection signal includes a controllable-light signal and the ambient light signal; and the cross manner is applied M times to let the capacitor circuit sample the inversion of the detection signal M times while the detection signal includes the ambient light signal without the controllable-light signal, wherein (N+M) equals (K+1).

Abstract: A photoplethysmography front-end receiver is capable of eliminating an error in the estimation of an ambient-light current. The receiver includes a current-to-voltage conversion circuit, an integrator, a switch circuit, and an analog-to-digital converter (ADC). The current-to-voltage conversion circuit converts an input current into a differential voltage signal. The integrator receives the differential voltage signal and outputs an analog output voltage. The switch circuit is set between the current-to-voltage conversion circuit and the integrator, forwards the differential voltage signal to the integrator in a first duration when a controllable light source is turned on, and forwards an inverted signal of the differential voltage signal to the integrator in a second duration when the controllable light source is turned off, wherein the second duration is after or before the first duration. The ADC generates a digital signal for analysis according to the analog output voltage after the second duration.

Abstract: The present invention provides an antenna structure, an antenna device and a wireless localization method. The antenna structure includes a first radiation unit including a plurality of first connecting portions and a plurality of first annular radiation portions, a second radiation unit including a plurality of second connecting portions and a plurality of second annular radiation portions, a first conductive wire and a plurality of second conductive wires. A first end of each first annular radiation portion is connected to the first connecting portion, and the second end thereof extends towards the first end of the adjacent first annular radiation portion. A first end of each second annular radiation portion is connected to the second connecting portion, and the second end thereof extends towards the first end of the adjacent second annular radiation portion.

Abstract: The present invention provides an antenna structure, an antenna device and a wireless localization method. The antenna structure includes a first radiation unit including a plurality of first connecting portions and a plurality of first annular radiation portions, a second radiation unit including a plurality of second connecting portions and a plurality of second annular radiation portions, a first conductive wire and a plurality of second conductive wires. A first end of each first annular radiation portion is connected to the first connecting portion, and the second end thereof extends towards the first end of the adjacent first annular radiation portion. A first end of each second annular radiation portion is connected to the second connecting portion, and the second end thereof extends towards the first end of the adjacent second annular radiation portion.