Abstract: System and method for measuring a gas concentration are provided. A ball sensor generates a collimated beam of a surface acoustic wave including fundamental wave of first frequency and harmonic wave of second frequency, which propagates through a orbital path on piezoelectric ball while passing through sensitive film to adsorb a target gas. Temperature control unit controls ball temperature of the ball sensor. Signal processing unit transmits a burst signal to sensor electrode of the ball sensor to excite the collimated beam, receives burst signals after the collimated beam has propagated a predetermined number of turns around the piezoelectric ball, and calculates the gas concentration and the ball temperature by first and second relative changes in delay times of the first and second frequencies, respectively, using waveform data of the burst signals.

Abstract: A collimated beam (23) of a surface acoustic wave propagates on a piezoelectric substrate (22) while passing through sensitive film (25) to adsorb a sensing gas. Signal processing unit (40) transmits an exciting burst signal to sensor electrode (24) to excite the collimated beam (23), receives first and second returned burst signals after the collimated beam (23) has propagated, and calculates a target gas parameter by a target leakage factor of the background gas and a relation between reference gas parameters and reference leakage factors of reference gases, the leakage factor is provided by first and second attenuations of the first and second returned burst signals, respectively, using waveform data of the first and second returned burst signals.

Abstract: A standard-moisture generator includes a flow controller configured to control a flow of a gas, a dryer connected to the flow controller, configured to absorb water molecules in the gas and to generate a dry gas having a background moisture, a moisture cell connected to the dryer, configured to add an object moisture to the dry gas, and a delay member connected to the moisture cell, configured to pass the dry gas with a delay time depending on a concentration of the background moisture in the dry gas.

Abstract: A standard-moisture generator includes a flow controller configured to control a flow of a gas, a dryer connected to the flow controller, configured to absorb water molecules in the gas and to generate a dry gas having a background moisture, a moisture cell connected to the dryer, configured to add an object moisture to the dry gas, and a delay member connected to the moisture cell, configured to pass the dry gas with a delay time depending on a concentration of the background moisture in the dry gas.

Abstract: A collimated beam (23) of a surface acoustic wave propagates on a piezoelectric substrate (22) while passing through sensitive film (25) to adsorb a sensing gas. Signal processing unit (40) transmits an exciting burst signal to sensor electrode (24) to excite the collimated beam (23), receives first and second returned burst signals after the collimated beam (23) has propagated, and calculates a target gas parameter by a target leakage factor of the background gas and a relation between reference gas parameters and reference leakage factors of reference gases, the leakage factor is provided by first and second attenuations of the first and second returned burst signals, respectively, using waveform data of the first and second returned burst signals.

Abstract: System and method for measuring a gas concentration are provided. A ball sensor generates a collimated beam of a surface acoustic wave including fundamental wave of first frequency and harmonic wave of second frequency, which propagates through a orbital path on piezoelectric ball while passing through sensitive film to adsorb a target gas. Temperature control unit controls ball temperature of the ball sensor. Signal processing unit transmits a burst signal to sensor electrode of the ball sensor to excite the collimated beam, receives burst signals after the collimated beam has propagated a predetermined number of turns around the piezoelectric ball, and calculates the gas concentration and the ball temperature by first and second relative changes in delay times of the first and second frequencies, respectively, using waveform data of the burst signals.