Patent ID: 8258862

Claim:
A demodulation circuit comprising: a first transistor comprising a channel formation region including an oxide semiconductor; a second transistor comprising a channel formation region including an oxide semiconductor; a first capacitor; a second capacitor; a third capacitor; a first resistor; and a second resistor, wherein a gate terminal of the first transistor, a drain terminal of the first transistor, a source terminal of the second transistor, and one terminal of the first capacitor are electrically connected to each other, wherein a gate terminal of the second transistor, a drain terminal of the second transistor, one terminal of the second capacitor, one terminal of the third capacitor, and one terminal of the first resistor are electrically connected to each other, wherein a source terminal of the first transistor, the other terminal of the second capacitor, the other terminal of the first resistor, and one terminal of the second resistor are electrically connected to each other, and wherein the other terminal of the third capacitor and the other terminal of the second resistor are electrically connected to each other.