Encoder, Interferometer, Parellel Mirrors
Tuesday, September 05, 2006
Lawrence N. Mertz (deceased) designed and developed an Interferometer Angular Encoder with nanoradian accuracy based on a hexflash phase analyzer circuit with an electronic circuit. The electronic system can solve the common phase output from a three-phase input (phase unwrapping plus a smoothing filter).
The Encoder is a Michelson interferometer, where the light beams are folded by a pair of parallel mirrors mounted on a mobile rotor module. The Encoder remains in alignment even after severe perturbations in all six degrees of freedom of the rotor module. The path difference is insensitive for five of degrees of freedom and only sensitive to one angle of rotor freedom. Using laser light beams and the parallel mirrors spaced at 12 cm, one million fringes per radian can be obtained. The Encoder can be adapted to a three-port lenticular fringe receiver by realigning the beamsplitter. This causes the returning beams to separate and then recombine through a lens providing fringes on the lenticular receiver. The rotor module has an operating range of 18 degrees and is counterbalanced for stability.
Performance of the Encoder is better than 1 nrad resolution over 3.7 mrad at a 2 MHz sample rate. Resolution can be improved to better than 100 prad by smoothing at a 3.3 KHz sample rate with an operating range of 18 degrees.
Design features are as follows: 1) The parallel mirrors are mounted as a separate module serving as the rotor of the encoder with the remaining stationary part, the stator of the encoder; 2) Optical path difference is independent of five degrees of freedom with angular sensitivity in only one degree of freedom; 3) Parallelism of the parallel mirrors is less than the normally required Fabry-Perot tolerance; 4) The rotor is mounted as a vertical pendulum from a pair of strings providing vertical tilt measurement; 5) Three sensing photodetectors view the light beams through a lenticular screen causing the display of the incident light beam pairs.
Source: Various Publications
Reference: None Available
Industrial Products
posted by JD52 @ 9:35 PM,
1 Comments:
-
At 7:15 AM,
lijialefw said...
-
To a nail, lost a war.(wow gold) In a particular press to see(wow power leveling) such a foreign minyan: In order to (wow gold)receive a nail, we have lost a mati Tie In order to(wow power leveling) get a piece of mati Tie, we have lost a Pi Junma In order to get(wow gold) a Pijun ma, we (wow power leveling)have lost a(wow gold) jockey; To be a jockey, we lost a war victory. This is the first (Rolex)under general minyan at(World of Warcraft gold) first glance, but careful consideration, you(wow power leveling) will find that it contains a layer of the important essence of life: learn to give up, have a maturity. To a mati Tie and eventually lead to (wow gold)lose a war, this is not know how early to give up the consequences. Wise said: two disadvantages of the value comes light, the right to( World of Warcraft gold)choose the two-phase benefit. a folder to be the tail of the gecko already know how to give up the tail, the preservation of(wow power leveling) life, let alone we are full of (power leveling)the wisdom of mankind? ! in everyone's life, always (powerleveling)have in the face of choice, a choice, there is bound to give up, we have to learn is to( power leveling)pay a painful price, to give up local interests and preserve the overall interests. In chess, there are not "abandoning single-car" this trick? as the saying goes: not old, not new. sometimes, even (power leveling)the most precious things to know in good time to give up. when you( powerleveling)graduated from junior high school, in the face of a sincere friendship, you(powerleveling )will Yiyibushe. But think back, and only bid farewell to middle school, high school usher in a(rs gold )new life, can meet new friends. The recent shift is not on this? Finally, a celebrity's life motto In( gold wow)conclusion: Life is like theater, everyone is their own lives in the only director. Only Institute of choice, people will know how to give up the Chewu life, Xiaokan life, the life Habitat has Seasky.
