Patent ID: 7180961

Claim:
A receiving device that receives a first modulated signal having a spread-spectrum modulation applied, and outputs a determination signal, the receiving device comprising: a correlational operation circuit that executes a correlational operation between the first modulated signal and a first spread-spectrum signal string, and outputs a first correlational signal; and a determination circuit that determines an amplitude value of the first correlational signal, and outputs the determination signal, the determination circuit including: a first detector that outputs a first detection signal, when the first detector detects that a value of the first modulated signal exceeds a first threshold value, a second detector that outputs a second detection signal, when the second detector detects that a value of the second modulated signal exceeds a second threshold value, a detected signal selector that outputs the determination signal of a first value, when the first detection signal is inputted, and outputs the determination signal of a second value, when the second detection signal is inputted, a first half-wave rectifier located on a pre-stage of the first detector, and an amplitude inverter and a second half-wave rectifier located on a pre-stage of the second detector, wherein the first half-wave rectifier applies a half-wave rectification to the first correlational signal, and outputs a first half-wave rectified signal to the first detector, wherein the amplitude inverter inverts the amplitude value of the first correlational signal, and outputs a second correlational signal, wherein the second half-wave rectifier applies the half-wave rectification to the second correlational signal, and outputs a second half-wave rectified signal to the second detector, and wherein the second detector outputs the second detection signal when the second detector detects that a value of the second half-wave rectified signal exceeds the first threshold value.