1 / 9

Round Trip Phase Measurement System

Round Trip Phase Measurement System. Terry Cotter. Requirements. IF Phase Stability Requirements Short Term <.5ps rms for times <1s Long Term <6ps linear slope over 30min IF Phase shift with pointing change <.7ps across whole sky <.07ps per degree of slew

myersc
Download Presentation

Round Trip Phase Measurement System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Round Trip Phase Measurement System Terry Cotter EVLA LO/IF PDR 22-23 January 2002

  2. Requirements • IF Phase Stability Requirements • Short Term <.5ps rms for times <1s • Long Term <6ps linear slope over 30min • IF Phase shift with pointing change • <.7ps across whole sky • <.07ps per degree of slew * specs apply after any RTP correction EVLA LO/IF PDR 22-23 January 2002

  3. Considerations • Fiber cable wrap • Needs to twist fiber not stretch it • Temperature effects on fiber • burial depth • insulating/temperature stabilizing exposed fiber • Laser/electronics stability • Dispersion in the Fiber EVLA LO/IF PDR 22-23 January 2002

  4. Temperature Considerations From EVLA Memo 10 Based on Duhamel’s theorem EVLA LO/IF PDR 22-23 January 2002

  5. Temperature Considerations Bottom line: For just the part buried @1m • Long term stability is .4 ps/s which meets the spec of 1.4 ps/s • Short term stability is .0002 ps/s which far exceeds the spec of .5 ps/s EVLA LO/IF PDR 22-23 January 2002

  6. Temperature Considerations • Do we really needs Round Trip Phase Correction? • YES • Long term stability is near Spec • Short term above ground and in the building • Good monitor of system problems EVLA LO/IF PDR 22-23 January 2002

  7. Other Considerations • Laser Stability • Unknown as to how much of a problem this is going to be • Dispersion in the fiber • Will need to operate RTP system near zero dispersion point of the fiber ~1310nm EVLA LO/IF PDR 22-23 January 2002

  8. EVLA LO/IF PDR 22-23 January 2002

  9. Side Note Two master rack are required, one for back up Round trip phase equipment can be used to monitor the master racks together. EVLA LO/IF PDR 22-23 January 2002

More Related