Abstract: An ultrasonic time measurement device measures a propagation time of a measurement wave transmitted from a first sensor to a second sensor. The device includes a transmission circuit that causes the first sensor to repeatedly transmit measurement waves one at a time and a reception circuit that detects reception at the second sensor, of the respective measurement wave transmitted from the first sensor. The device further measures elapsed times for the measurement waves, each of the elapsed times being an elapsed time from a reference time to a reception time of the respective measurement wave received by the second sensor and calculate the propagation time of the measurement wave from the first sensor to the second sensor based on the elapsed times measured by the time measurer.

Abstract: In gas analyzing apparatuses, interference noises should be reduced. A gas analyzing apparatus for analyzing component included in measuring object gas, including: a light emitting unit to irradiate laser light to the measuring object gas; a light receiving unit to receive the laser light having passed through the measuring object gas; an actuating unit to change an optical path length of the laser light by moving at least one optical element that is arranged in a light path where the laser light is passing; and a calculating unit to calculate concentration of the measuring object gas, based on signals detected by the light receiving unit in two states where the optical element is at different positions by n/2 times the wavelength of the laser light (where, n is integer) is provided.

Abstract: In gas analyzing apparatuses, interference noises should be reduced. A gas analyzing apparatus for analyzing component included in measuring object gas, including: a light emitting unit to irradiate laser light to the measuring object gas; a light receiving unit to receive the laser light having passed through the measuring object gas; an actuating unit to change an optical path length of the laser light by moving at least one optical element that is arranged in a light path where the laser light is passing; and a calculating unit to calculate concentration of the measuring object gas, based on signals detected by the light receiving unit in two states where the optical element is at different positions by n/2 times the wavelength of the laser light (where, n is integer) is provided.