In reference to a digital equalizer such as a feed-forward equalizer
(FFE), what does a "slicer" do, and how does it do it?
In reference to decision feedback equalization (DFE), what does a
tailed DFE do, and how does it do it?

It seems like the slicer is a signal processor
circuit for noise cancellation. Information from 
the slicer is used to determine if any noise is
present. Any signal detected at this point is fed
back to the slicer's input, and is used to cancel
the noise. Looks like a standard inverted signal
cancellation process. I can go into that more if
you need to know details.

The tailed DFE, I can't find yet, but still looking.

Rather interesting info regarding these TLA's. Is
this in reference to HDSL2?

-AI

Hello philipa-ga,

A feed-forward equalizer (FFE) mainly performs phase equalization. For
optimum performance of a FFE it might be necessary to "clean up" the
input signal.
A slicer can be defined as an electronic circuit which judges the
voltage level of an input signal to be above or below a voltage
threshold. For example the Schmitt Trigger is a circuit with input
thresholds. It is capable of transforming slowly changing input
signals into sharply defined, jitter-free output signals.
You can find details of the operation of a typical Schmitt Trigger at
the following link:

www.philipslogic.com/products/hc/pdf/74hc14.pdf 


A decision slicer is used with a decision feedback equalizer (DFE) to
format, or to resolve symbols in, the equalized data.

The decision signal for a DFE can be obtained from either a training
sequence or can be decision-directed. Therefore I wonder if you might
have meant to say "trained DFE" rather than "tailed DFE".

You will find a good explanation of equalization in the document
"equalization2.pdf"  at the following link:

http://www.eecg.toronto.edu/~johns/nobots/courses/ece1392/

I do hope I have understood your question and that the above
information is useful to you.

Hello AI:
Thanks for the comment. I think that West may be closer, since my
context seems to fit the Schmitt trigger idea better. What is TLA and
HDSL2?
Hello West:
Thanks for your pointer to the slicer, I think that gives me enough to
be going on with, and also for your link to John's U of T. I had found
some of his material in my own searches, but not that particular one.
To both of you:
I'm beginning to have doubts about the tailed DFE, but the phrase (or
tail DFE) does occur two or three times in my material, so I really
don't know if it should be trained. I'll check with my original
source!