The ALMA requires a coherent local oscillator at each antenna. Due to the long distribution length from central building to each of the antennas, the fiber optic path to each antenna must be stabilized to meet the ALMA specification. A round trip phase correction technique has been adopted to meet these specifications, and that technique is described here. Also, a summary of various techniques that have been used at other installations is given. Results reported here are given for tests completed through April, 2002. Further tests are planned and will be reported at a later date.
View a pdf version of ALMA Memo #443.
Last modified: 2003-01-28
alma-memos@nrao.edu