Signal processing device and search method
Provided is a sensor device being a signal processing device, including: a capacitor; a sensor unit configured to wirelessly transmit, in a case in which electric power of a predetermined amount or more is accumulated in the capacitor, a first signal (SG 1 ) through use of the electric power accumulated in the capacitor; a reception unit configured to receive a radio wave transmitted from a power transmission device being an external device; and a transmission antenna functioning as a second transmission unit, the transmission antenna being configured to wirelessly transmit, in response to reception of the radio wave, a response signal (SG 3 ) being a second signal generated based on the received radio wave without using the electric power accumulated in the capacitor.
1 . A signal processing device, comprising:
a capacitor;
a first transmission unit configured to wirelessly transmit, in a case in which electric power of a predetermined amount or more is accumulated in the capacitor, a first signal through use of the electric power accumulated in the capacitor;
a power generation circuit configured to generate electric power owing to presence of a detection target, wherein the electric power generated by the power generation circuit is accumulated in the capacitor, the detection target comprises a liquid;
a reception unit configured to receive a radio wave transmitted from an external device; and
a second transmission unit configured to wirelessly transmit, in response to reception of the radio wave, a second signal generated based on the received radio wave without using the electric power accumulated in the capacitor.
2 . The signal processing device according to claim 1 , wherein the second signal is a harmonic wave of the radio wave, the harmonic wave being generated in the reception unit which has received the radio wave.
3 . The signal processing device according to claim 2 ,
wherein the reception unit includes a rectification circuit configured to rectify the radio wave so as to obtain electric power, and
wherein the second signal includes a harmonic wave generated during rectification performed by the rectification circuit.
4 . The signal processing device according to claim 1 ,
wherein the reception unit includes a rectification circuit configured to rectify the radio wave so as to obtain electric power, and
wherein the electric power obtained by the rectification circuit is accumulated in the capacitor.
5 . The signal processing device according to claim 4 , further comprising a power generation circuit,
wherein the rectification circuit is connected to the capacitor via the power generation circuit, and
wherein the electric power obtained by the rectification circuit is supplied to the capacitor through a path in which electric power generated by the power generation circuit is to be transmitted.
6 . The signal processing device according to claim 5 ,
wherein the power generation circuit includes an electrode, and
wherein the rectification circuit is connected to the electrode so that the electric power obtained by the rectification circuit is allowed to be supplied to the capacitor via the electrode.
7 . The signal processing device according to claim 1 ,
wherein the first transmission unit includes a signal processing circuit, and
wherein the signal processing circuit is a battery-less circuit configured to operate through use of the electric power generated by the power generation circuit as power supply electric power.