 |
 |
 |
 |
Let me add my two-cents to this discussion. The best place for the
log amp is in software. With the advent of relatively cheap 14-16 bit
ADCs all data could be collected as high resolution "raw" or linear
data. Any transforms such as log or fluorescence compensation (or
cube-root for that matter) could then be performed mathematically,
which avoids the problems being examined in the current discussion.
The Coulter XL is one instrument that is starting to move in this
direction.
>> It sounds like the search for the Holy Grail - to be able to do away with log
amps by digitizing a wide range linear signal Howard Shapiro (and others) have
been talking about this for years. Bob Auer from Coulter gave, at the last ISAC,
a very good talk of the difficulties in doing this - it involves a lot more than
just doing 16 bits of conversion. Hardware technology, however, IS catching up
and allowing designers to work with raw signals and do all the processing
(logging, compensation) in real time on digital data. I would expect to see some
more about this at the next ISAC.
-Marty Bigos
Stanford Shared FACS Facility
|
|
|
|