thanks + how to detect a persistent signal anomaly

(i'm posting here because i could adopt both an hardware or software
solution (having a fixed point dsp available); _if you think i'm
off-topic_ and that the solution lies on the software side, i can
re-post the question on comp.dsp, virtually "closing" the thread
here...)


hello

i would like to thank you for the answers to this thread
http://groups.google.com/group/sci.electronics.design/browse_thread/thread/fe64351e91dfcff1/399783a22eb72bb4#399783a22eb72bb4

which have been *extremely* useful and effective both in understanding
my problem better and as a solution; after some exploration we chose a
specific gaussian filter which - for the kind of application i'm
working on - behaves "spectacularly well" ;-)



now to _my current problem_ (i'm looking for *any generic hint about
the subject*, then i will google about what you suggest):

i would like to recognize an incoming persistent anomaly of the signal
(for example "sudden offset increase": what should be "zero" suddenly
becomes +2 because of sudden voltage skew and stays like that for a
reasonably long amount of time (not a "spike"), or sudden "white noise"
because a wire gets loose, or....)

i would like to do that "as fast as possible" (where "fast" means "with
the shortest latency/delay possible with respect to the appearance of
the anomaly on the signal")


does exist a standard way of dealing with anomalies? a "toolset of
procedures" i can study to understand what i can do?


since i think that the kind of problems i can face could be related to
the sensor technologies: i'm using cheap micromachined capacitive
accelerometers. the system can tolerate the specific sensor noise but i
don't know how they can _malfunction_.


thank you again, guys!
gst

.