Abstract:
A gas analyzer which employs a tunable laser is described. The laser is tunable over a well defined bandwidth so that coherent energy of all frequencies within the bandwidth is available. A known gas is introduced into the laser cavity so that the laser will lase only at the frequencies which correspond to the absorption frequencies of the gas. The output of the swept laser is therefore a reference spectrum containing a series of lines which correspond to the absorption frequencies of the known gas. The reference spectrum is therefore uniquely characteristic of the known gas. By illuminating a sample of an unknown gas with the reference spectrum some of, or all of, the peaks will be absorbed when the unknown gas partially, or completely, is composed of gases identical to those of the reference gas. The illumination from the unknown gas is detected with a broad band detector and the composition of the unknown gas identified by noting which of the reference spectrum peaks are absorbed and by the amount they are absorbed.
Abstract:
An interferometer having a frequency tunable laser generator for reflecting laser light from a movable mirror to provide an optical interference fringe pattern. A servo circuit, that includes detectors for receiving the optic fringe pattern and providing output signals whenever any displacement of the movable mirror causes the fringes to begin moving, automatically adjusts the frequency of the laser light signal to maintain the fringes in a fixed position. The direction and magnitude of the frequency variation of the laser signal required to hold the fringes in a fixed position is measured to determine the direction and magnitude of mirror displacement.
Abstract:
A tire pressure indicating arrangement in which a passive transponding element is used as the tire pressure condition responsive sensor at each tire and an active transmitter is used to interrogate either successively or simultaneously each transponder, each of which is in turn adapted to transpond back to a receiver in response to the transmitter signal in the event tire pressure declines to an unsafe level. The receiver signal is then used to activate an alarm or indicating device.