公开(公告)号：US5202570A

公开(公告)日：1993-04-13

申请号：US673886

申请日：1991-03-22

申请人： Hiroaki Tanaka ,  Masayuki Matsuura ,  Hideo Tai ,  Kiyoji Uehara

发明人： Hiroaki Tanaka ,  Masayuki Matsuura ,  Hideo Tai ,  Kiyoji Uehara

IPC分类号： G01N21/39 ,  G02B3/00

CPC分类号： G02B3/00 ,  G01N21/39 ,  G01N2021/399

摘要： A gas detection device employs a tunable wavelength laser, modulated about an absorption line of a gas to be detected. By measuring the ratio of the fundamental to the second harmonic of the modulation frequency, the detection is independent of the optical path length. This permits an aimable device in which a laser beam is directed toward a remote surface, reflected thereby, and the reflected beam focused upon a detector. The presence of the gas to be detected in the space between the device and the reflective surface is thereby determined.

公开(公告)号：US4745606A

公开(公告)日：1988-05-17

申请号：US841913

申请日：1986-03-20

申请人： Kiyoji Uehara ,  Hiroaki Tanaka ,  Takashi Ueki ,  Hideo Tai

发明人： Kiyoji Uehara ,  Hiroaki Tanaka ,  Takashi Ueki ,  Hideo Tai

IPC分类号： G01N21/39 ,  H01S3/00 ,  H01S3/08 ,  H01S3/101 ,  H01S3/105 ,  H01S3/106 ,  H01S3/139 ,  H01S5/0683 ,  H01S5/14 ,  H01S5/40 ,  H01S3/10 ,  H01S3/13

CPC分类号： H01S5/14 ,  H01S3/105 ,  H01S3/1061 ,  H01S3/1392 ,  H01S2301/04 ,  H01S3/0809 ,  H01S5/06832 ,  H01S5/4087

摘要： A dual-wavelength laser apparatus includes a laser emitting a laser beam consisting of two wavelength components, a methane cell for controlling and equalizing gains of the two wavelength components, a cavity length modulator including a piezoelectric element for periodically modulating the cavity length of the laser, and a feedback circuit for controlling the modulation center such that the sum of outputs of the two modulated wavelength components is kept substantially constant. The feedback circuit includes a detector for detecting a laser output, a lock-in amplifier for detecting and amplifying an output from the detector, an integrator for integrating an output from the lock-in amplifier, and a high-voltage amplifier for generating a bias voltage set by the integrator.

摘要翻译： 双波长激光装置包括发射由两个波长分量组成的激光束的激光器，用于控制和均衡两个波长分量的增益的甲烷单元，包括用于周期性地调制激光器的腔长度的压电元件的腔长调制器 以及用于控制调制中心的反馈电路，使得两个调制波长分量的输出之和保持基本恒定。 反馈电路包括用于检测激光输出的检测器，用于检测和放大来自检测器的输出的锁定放大器，用于对来自锁定放大器的输出进行积分的积分器和用于产生偏置的高压放大器 由积分器设置的电压。

公开(公告)号：US5432752A

公开(公告)日：1995-07-11

申请号：US188707

申请日：1994-01-31

申请人： Takanori Ito ,  Hideo Tai

发明人： Takanori Ito ,  Hideo Tai

IPC分类号： G01S15/10 ,  G01B17/00 ,  G01S7/52 ,  G01S7/526 ,  G01S11/14 ,  G01N29/22

CPC分类号： G01B17/00 ,  G01S7/52006 ,  Y10S367/902

摘要： A calibration pipe having a predetermined length is connected to an end of a pipe to be measured. A sound emitter and a sound receiver are connected to a base end of the calibration pipe. The sound emitter emits a sound into the calibration pipe and the pipe to be measured, and the sound receiver receives a sound reflected from a discontinuous portion of the pipe. A calculator is provided for calculating a period of time from emitting of the sound to receiving of the reflected sound. The length of the pipe is calculated based on speed of the sound in the calibration pipe.

摘要翻译： 具有预定长度的校准管连接到要测量的管的一端。 声发射器和声音接收器连接到校准管的基端。 声发射器将声音发射到校准管和待测量的管道中，并且声音接收器接收从管的不连续部分反射的声音。 提供了一种计算器，用于计算从发出声音到接收反射声音的时间段。 管道的长度根据校准管道中的声音速度计算。