Thanks, I'll check it out.
Yeah, that's the TMUX thing. Our 75-MHz low noise VCA product combines a normal powers-of-2 PGA with a 4-bit attenuator that's built like an R-2R network (i.e. a ladder with switches in the shunt branches) except that its gain varies from 1 to 9/16. By picking the resistors properly you can do a good job, though the combination isn't necessarily monotonic at the ends of the range, so it needs calibrating. (The VCA is mainly intended for use with MPPCs to replace PMT modules.)
Cheers
Phil Hobbs