Measuring and testing – Fluid pressure gauge – Photoelectric
Reexamination Certificate
2007-05-29
2007-05-29
Lefkowitz, Edward (Department: 2855)
Measuring and testing
Fluid pressure gauge
Photoelectric
C356S437000
Reexamination Certificate
active
10894309
ABSTRACT:
A method of monitoring pressure of a gas species up to at most a predetermined maximum pressure value is disclosed. The method includes exposing the gas species to transmission of laser light, periodically modulating the wavelength of the laser light over a wavelength band including at least one absorption line of the gas species, optoelectrically converting the transmitted laser light, thereby generating an electric output signal, performing at least one of first filtering the electric output signal with a filter characteristic having a lower cut-off frequency not lower than a transition frequency and of second filtering the electric output signal with a bandpass filter characteristic having an upper cut-off frequency not higher than the transition frequency and a lower cut-off frequency above the modulation frequency of the periodic wavelength modulation. The output of at least one of the filterings is evaluated as a pressure indicative signal.
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Fehr Jean-Noel
Lehmann Martin
Liechti Martin
Schnell Urban
Allen Andre
Antonelli, Terry Stout and Kraus, LLP.
Lefkowitz Edward
Lehmann Martin
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