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pyDevSup/iocBoot/iocFPM/fpm.py
Michael Davidsaver 7959e54ff9 nsls2 FPM
2015-06-19 14:12:13 -04:00

164 lines
4.8 KiB
Python

# -*- coding: utf-8 -*-
"""
Processing of Filling Pattern Monitor digitizer data.
"""
import logging
_log = logging.getLogger(__name__)
import time
import numpy
from scipy import signal
from devsup.util import Worker
from devsup.hooks import initHook
from devsup.dset import AsyncOffload
bucketPturn = 1320 # NSLS2
sampPbucket = 16 # ~= 8GHz/500MHz
sampPturn = bucketPturn*sampPbucket
# Since digitizer sample clock is not sync'd
# to the signal the bunch phase will change
# over the course of the trace.
#
# To compensate for this we should resample w/ interpolation,
# but this is expensive and may distort the signal.
#
# Instead make a coarse correction by periodically dropping
# a sample to simulate a sync'd sample clock
#
# This lets us pretend that there are exactly 16 samples per
# period of the signal
Fsamp = 8e9 # ADC samples frequency
Fsig =499.68e6 # frequency of signal being sampled
mult = Fsamp/Fsig # samples per signal period
nPb = int(mult)
assert nPb==sampPbucket
remd = mult-nPb
assert remd<0.5 and remd>0, "assumption violated" # remd==0 drops no samples, remd>0.5 should add samples
delta = int(numpy.round(nPb/remd))
print 'fpm delta mult', nPb, 'frac', delta
def deleteEveryNth(arr, N):
'''Optimized version of
return numpy.delete(arr, numpy.arange(0, len(arr), N))
'''
iS = range(0, len(arr), N)
parts = [None]*len(iS)
for e,i in enumerate(iS):
parts[e] = arr[i+1:i+N]
return numpy.concatenate(parts)
class Dev(AsyncOffload):
inputs = {
'A':'raw', # array copy
'B':'nskip',
'C':'thres',
'D':'scale',
'E':'offset',
}
outputs = {
'VALA':'fill', # array copy
'VALB':'phase', # array copy
'VALD':'nwbeam',
'VALE':'total',
'VALF':'minv',
'VALG':'maxv',
'VALH':'mini',
'VALI':'maxi',
'VALJ':'pvar',
'VALK':'turns',
}
timefld = 'VALC' # store execution time
def inThread(self, raw=None, nskip=0, thres=0.01, scale=1.0, offset=0, **kws):
raw = signal.detrend(raw[nskip:], type='constant')
# remove every delta'th sample
raw = deleteEveryNth(raw, delta)
# truncate to whole turns
turns = len(raw)/sampPturn
raw = raw[:turns*sampPturn]
# determine buckets w/ beam
val = raw.reshape(turns, bucketPturn, sampPbucket)
# Which buckets have beam?
# average over turns
# find buckets where peak to peak voltage exceeds threshold
hasbeam = val.mean(0).ptp(1)>thres
nwbeam = hasbeam.sum()
if nwbeam>0:
# fine tune sync.
# find peak position for each turn by averaging all buckets w/ beam
peaksamp = val[:,hasbeam,:].argmax(2).mean(1)
turnshift = numpy.round(peaksamp).astype(numpy.uint8)
turnval = raw.reshape(turns, sampPturn)
# shift turns to align peak with turn zero.
## Warning, this mixes signals for buckets 0 and 1319 in adjecent turns
turn0shift = turnshift[0]
for i in range(16):
turnval[turnshift==i,:] = numpy.roll(turnval[turnshift==i,:], turn0shift-i, axis=1)
val = turnval.reshape(turns, bucketPturn, sampPbucket)
# sum samples over each RF bucket
# offset compensates for summing of digitizer noise
Ival = numpy.abs(val).sum(2) - offset
# after subtraction the "current" may be negative, but this
# will mess up the automatic re-scaling, so force non-negative
Ival[Ival<0] = 0.0
fillbyturn = Ival.mean(1) # average buckets
fill = Ival.mean(0) # average turns
if scale>0.0:
S1 = scale/fill.sum()
fill *= S1
S2 = scale/fillbyturn[0]
fillbyturn *= S2
#print 'factor', S1, S2
else:
fill = numpy.zeros(fill.shape, dtype=fill.dtype)
fillbyturn = numpy.zeros(fillbyturn.shape, dtype=fillbyturn.dtype)
phase = val.mean(1).mean(0) # sum over turns and buckets to get the approx. bunch signal shape
if nwbeam>0:
bfill = fill[hasbeam]
bindx = numpy.arange(fill.shape[0])[hasbeam]
pvar = (bfill.max()-bfill.min())/(bfill.max()+bfill.min())*100.0
else:
bfill = numpy.asarray([0.0])
bindx = numpy.asarray([0])
pvar = 0.0
#print 'ellapsed 2 %.03f'%(time.time()-TS)
return {
'ok':True,
'fill':fill,
'turns':fillbyturn,
'phase':phase,
'nwbeam':hasbeam.sum(),
'total':fill.sum(),
'minv':bfill.min(),
'maxv':bfill.max(),
'mini':bindx[bfill.argmin()],
'maxi':bindx[bfill.argmax()],
'pvar':pvar,
}
build = Dev