Jitter in USdigital encoders

I understand that with rotary vibration of the shaft of an encoder
errors can result due to dithering or jittering, effectively extra
pulses that shouldn't be there.

Does the circuitry in a USdigital encoder take care of this? or is
some external filtering required??


This is for a homebrew digitizing arm project, seen here:

http://www.cnczone.com/forums/showthread.php?t=4424

I/We are thinking that homebrew DRO software might be modified to
include a capture function. Then software to convert the co-
ordinates from the joints to 3D co-ordinates could be written.

Cheers,

Graham