Patent ID: 7477182

Claim:
A pulse radar system comprising: a transmitting circuit transmitting a transmission pulse wave that has already been modulated by a transmission pulse; a transmitting antenna radiating the transmission pulse wave from the transmitting circuit; a receiving antenna receiving a reception pulse wave, the reception pulse wave being radiated from the transmitting antenna as a transmission pulse wave and reflected from an obstacle; a receiving circuit controlling a gain, the receiving circuit demodulating the reception pulse wave from the receiving antenna and outputting a reception pulse; and a gain control circuit (a) generating a gain control signal corresponding to an amplitude of the reception pulse, the reception pulse being obtained in response to a gain control transmission pulse wave, and (b) controlling, by the gain control signal, a gain of the reception pulse wave or the reception pulse obtained in response to a measurement transmission pulse wave, the gain control transmission pulse wave being transmitted from the transmitting circuit for controlling a gain in the receiving circuit, the measurement transmission pulse wave being transmitted, after the gain control transmission pulse wave, from the transmitting circuit for measuring the distance to the obstacle, wherein the measurement transmission pulse wave has a pulse width that is proportional to a distance from the pulse radar system to a measurement zone, such that, among a plurality of measurement zones predetermined based on a respective distance to a respective obstacle, the greater the respective distance, the wider the pulse width of the respective measurement transmission pulse wave.