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152 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
""" CREATED: 7/2012
AUTHOR: TOMÁŠ ODSTRČIL
"""
from numpy import *
from string import find
from pygolem_lite.modules import save_adv_par
import os
#This function loads the binary data from a Tektronix ".ISF"
#file. The ISF file format is used by newer Tektronix
#TDS-series oscilloscopes.
#USAGE
#(v,t,h) = isf_read('ch1.isf.gz', 'gzip')
#INPUT
#filename - name of Tektronix ISF file, or gziped ISF file
#OUTPUT
#x - evenly spaced column-vector of x-values
#y - corresponding column-vector of y-values
#head - header record of file
def getfloat(string,pattern):
ii = find(string,pattern) + len(pattern)
z = string[ii:].split(';')[0]
return float(z)
def getint(string,pattern):
ii = find(string,pattern) + len(pattern)
z = string[ii:].split(';')[0]
return int(z)
def getstr(string,pattern):
ii = find(string,pattern) + len(pattern) + 1
z = string[ii:].split(';')[0]
return z
def getquotedstr(string,pattern):
ii = find(string,pattern) + len(pattern) + 1
z = string[ii:].split('"')[1]
return z
def isf_read(filename):
if not os.path.exists(filename):
raise IOError, "Missing .isf file"
if os.path.getsize(filename) == 0:
raise IOError, "Empty .isf file"
f = open(filename, "rb")
offset = 0
#offset
f.seek(offset,0)
hdata = f.read(511)
class HeadFile:
def __init__(self):
pass
head = HeadFile()
head.byte_num = getint(hdata,'BYT_N')
head.bit_num = getint(hdata,'BIT_N')
head.encoding = getstr(hdata,'ENC')
head.bin_format = getstr(hdata,'BN_F')
head.byte_order = getstr(hdata,'BYT_O')
head.setting = getquotedstr(hdata,'WFI')
head.point_format = getstr(hdata,'PT_F')
head.x_unit = getquotedstr(hdata,'XUN')
head.x_zero = getfloat(hdata,'XZE')
head.x_increment = getfloat(hdata,'XIN')
head.pt_off = getfloat(hdata,'PT_O')
head.y_unit = getquotedstr(hdata,'YUN')
head.y_multipt_const = getfloat(hdata,'YMU')
head.y_zero = getfloat(hdata,'YZE')
head.y_offset = getfloat(hdata,'YOF')
head.n_samples = getint(hdata,'NR_P')
# nevím jestli jsou potřebné
head.vscale = getfloat(hdata,'VSCALE')
head.hscale = getfloat(hdata,'HSCALE')
head.vpos = getfloat(hdata,'VPOS')
head.voffset = getfloat(hdata,'VOFFSET')
head.hdelay = getfloat(hdata,'HDELAY')
print head.setting
if head.encoding !='BIN' or head.bin_format != 'RI' or head.point_format != 'Y':
f.close()
print 'Unable to process IFS file.'
if head.byte_order == 'MSB': # Big Endian encoding
machineformat = '<'
elif head.byte_order == 'LSB': # little-endian encoding
machineformat = '>'
else:
print 'Unrecognized byte order.'
ii = find(hdata,'#')
f.seek(ii+1+offset,0)
skip= int(f.read(1))+1
f.seek(skip,1)
data_type = machineformat+'i'+str(head.byte_num)
data = fromstring(f.read(), dtype= data_type,count = head.n_samples )
f.close()
v = head.y_zero + head.y_multipt_const*(data - head.y_offset)
#v = v.astype('float32')
t = head.x_zero + head.x_increment*arange( head.n_samples)
save_adv_par(filename[:-4],t,data, scale = head.y_multipt_const)
return single(v),single(t),head
def isf2array(filename, compression = None):
v,t,h = isf_read(filename, compression)
return vstack([t,v]).T
#(v,t,h) = isf_read('ch1.isf')
#from matplotlib.pyplot import *
#plot(t,v)
#show()
|
