Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/pub/people/vlbi/evlbi/memos/eVLBI_VSIB_clock_termination_mod.pdf Дата изменения: Tue Nov 15 05:38:44 2005 Дата индексирования: Fri Dec 28 16:30:11 2007 Кодировка: Поисковые слова: star

EVLBI VSIB PCB Modifications For Clock Split-Termination & Connector Grounding ­ Suits VSI Board Version From Apr 2002 1) Remove resistor R23 (this is the clock termination resistor) 2) Solder a split termination resistance with a bleeder capacitor to GND. a. Tombstone a 50R (0603 case size) resistor on each of the pads in the location of component R23. b. Solder a 100pF (0805 case size) capacitor so that one of its ends connects to an end of each of the two tombstoned resistors. c. Solder a connecting wire from the unconnected end of the capacitor to the closest GND point on the PCB. Photos 2 & 3 detail this modification. 3) Make a connection with a suitably gauged wire between the GND connection of connector J2 to the closest possible GND point on the PCB. Done on the rear of the PCB. Photo 5 details this modification.

Photo 1 ­ Front View Of VSIB PCB

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EVLBI VSIB PCB Modifications For Clock Split-Termination & Connector Grounding ­ Suits VSI Board Version From Apr 2002

Photo 2 ­ Close-Up View Of Clock Termination Modification

Photo 3 ­ Close-Up View Of Clock Termination Modification Showing "Tombstoning" Of Split Termination Resistors

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EVLBI VSIB PCB Modifications For Clock Split-Termination & Connector Grounding ­ Suits VSI Board Version From Apr 2002

Photo 4 ­ Rear View Of VSIB PCB

Photo 5 ­ Close-Up View Of Connector Grounding Modification

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