This module provides source code for aSub
records that support collecting history waveforms
for specified ai PV's, along with some simple
signal analysis of waveforms to provide, MIN,
MAX, AVG, RMS, and StdDev values.

(I,Q) to polar (R,T) conversion is also supported.

Release R0.5.0, Jan 2013.
Slope and Offset added

Release R1.9.0, Oct 2013
X-AXIS waveform added

TODO: Consider merging in ANL's waveProc module
to add FFT spectrum analysis and additional 
waveform signal statistics.

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How to use the history module:

Replace "sample" below w/ your app name
Add to $(TOP)/configure/RELEASE
CALC=<path to calc module release's $(TOP)
HISTORY=<path to history module release's $(TOP)
Add to $(TOP)/sampleApp/src/Makefile
SAMPLE_DBD += history
SAMPLE_DBD += calcSupport
SAMPLE_LIBS += calc
SAMPLE_LIBS += history

In your $(TOP)/sampleApp/Db directory
Create substitutions files, based on examples in history
release's db, archive, and autosave directories

#	For a generic PV history with a set of history buffers
	defined by the pattern file $(HISTORY)/db/ai_hist_pattern.db
			See ai_hist.substitutions
	You can also create a custom history pattern using
	ai_hist_pattern.substiutions as an example, and
	use it instead of ai_hist_pattern.db in your version
	of ai_hist.substitutions.
	Related files:
		history.tpl-arch,     archives  stats for a PV's full set of history buffers
		history.tpl-req,      autosaves stat limits for a PV's full set of history buffers
		hist_LAST_N.tpl-arch, archives  stats for a PV's LAST_N history buffer
		hist_LAST_N.tpl-arch, autosaves stat limits for a PV's LAST_N history buffer

#	For a PV history with a bootup configurable buffer size
		See ai_hist_last_x.substitutions

#	For Waveform analysis, try wave_proc_hist.substitutions
	For each waveform update, it uses wave_proc.template to compute:
		max, min, avg, rms, stdDev, slope, and offset
		keeps history of these stats with configurable intervals
	Related files:
		wave_proc.tpl-arch, archives stats for the waveform from wave_proc.template
		wave_proc.tpl-req,  autosaves stat limits for the waveform from wave_proc.template


Finally, update the build macros in $(TOP)/sampleApp/Db/Makefile,
substituting sample_hist for the substitution filenames
you create from the samples in the history module. 
DB		+= sample_hist.db
ARCHIVE += sample_hist.arch
REQ     += sample_hist.req