--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/HP3562A/trace_decoder.py Tue Dec 18 00:23:10 2007 +0100
@@ -0,0 +1,145 @@
+# -*- coding: utf-8 -*-
+"""
+trace_decoder
+=============
+
+Module for decoding a trace generated by the HP3562A DSA, using the
+GPIB command "DDBN" (Dump Data BiNary).
+
+This file can be exectued as a python script. Use '-h' for more informations.
+"""
+import struct
+import numpy
+from HP3562A import format_header, decode_float, decode_string, decode_header
+from HP3562A.enum_types import *
+
+
+HEADER = [ ("Display function", EDSP, 'h', 2),
+ ('Number of elements', int, 'h', 2),
+ ('Displayed elements', int, 'h', 2),
+ ('Number of averages', int, 'h', 2),
+ ('Channel selection', ECH, 'h', 2),
+ ('Overflow status', EOVR, 'h', 2),
+ ('Overlap percentage', int, 'h', 2),
+ ('Domain', EDOM, 'h', 2),
+ ('Volts peak/rms', EVLT, 'h', 2),
+ ('Amplitude units', EAMP, 'h', 2),
+ ('X axis units', EXAXIS, 'h', 2),
+ ('Auto math label', str, 's', 14),
+ ('Trace label', str, 's', 22),
+ ('EU label 1', str, 's', 6),
+ ('EU label 2', str, 's', 6),
+ ('Float/Interger', bool, 'h', 2),
+ ('Complex/Real', bool, 'h', 2),
+ ('Live/Recalled', bool, 'h', 2),
+ ('Math result', bool, 'h', 2),
+ ('Real/Complex input', bool, 'h', 2),
+ ('Log/Linear data', bool, 'h', 2),
+ ('Auto math', bool, 'h', 2),
+ ('Real time status', bool, 'h', 2),
+ ('Measurement mode', EMEAS, 'h', 2),
+ ('Window', EWIN, 'h', 2),
+ ('Demod type channel 1', EDEMOD, 'h', 2),
+ ('Demod type channel 2', EDEMOD, 'h', 2),
+ ('Demod active channel 1', bool, 'h', 2),
+ ('Demod active channel 2', bool, 'h', 2),
+ ('Average status', EAVG, 'h', 2),
+ ('Not used', int, 'hh', 4),
+ ('Samp freq/2 (real)', decode_float, None, 4),
+ ('Samp freq/2 (imag)', decode_float, None, 4),
+ ('Not used', decode_float, None, 4),
+ ('Delta X-axis', decode_float, None, 4),
+ ('Max range', decode_float, None, 4),
+ ('Start time value', decode_float, None, 4),
+ ('Expon wind const 1', decode_float, None, 4),
+ ('Expon wind const 2', decode_float, None, 4),
+ ('EU value chan 1', decode_float, None, 4),
+ ('EU value chan 2', decode_float, None, 4),
+ ('Trig delay chan 1', decode_float, None, 4),
+ ('Trig delay chan 2', decode_float, None, 4),
+ ('Start freq value', decode_float, None, 8),
+ ('Start data value', decode_float, None, 8),
+ ]
+
+def decode_trace(data):
+ """
+ Decode the data (as generated by the HP3562A DSA in response to a
+ "DDBN" command), and returns a couple (header, values).
+
+ header is the dictionnary of the header of the dumped data block,
+ value is a numpy array holding the trace (vector of float or
+ complex values).
+ """
+ header, idx = decode_header(data, HEADER)
+ resu = []
+ for i in range(header["Number of elements"]):
+ resu.append(decode_float(data[idx: idx+4]))
+ idx += 4
+ return header, numpy.array(resu, dtype=float)
+
+
+
+def main():
+ import sys
+ import optparse
+ opt = optparse.OptionParser("A simple tool for tracing a dumped trace")
+ opt.add_option('-f', '--filename', default=None,
+ dest='filename',
+ help='Output filename. If not set, read from stdin')
+ opt.add_option('-m', '--mode', default='binary',
+ dest='mode',
+ help='Dumping mode (may be "binary" [default], "ascii" or "ansi")',
+ )
+ opt.add_option('-d', '--display-header', default=False,
+ action="store_true",
+ dest="displayheader",
+ help="Display the trace header")
+ opt.add_option('-P', '--noplot-trace', default=True,
+ action="store_false",
+ dest="plot",
+ help="Do not display the plot of the trace")
+ opt.add_option('-x', '--xmode', default='lin',
+ dest='xmode',
+ help='X coordinate mode (may be "lin" [default] or "log")')
+ opt.add_option('-y', '--ymode', default='lin',
+ dest='ymode',
+ help='Y coordinate mode (may be "lin" [default], "log" or "db")')
+
+ options, argv = opt.parse_args(sys.argv)
+
+
+ if options.filename is None:
+ print "Can't deal stdin for now..."
+ sys.exit(1)
+ try:
+ header, data = decode_trace(open(options.filename, 'rb').read())
+ except Exception, e:
+ print "ERROR: can't read %s an interpret it as a HP3562 trace"%options.filename
+ print e
+ sys.exit(1)
+
+ if options.displayheader:
+ print format_header(header, HEADER, 100)
+ if options.plot:
+ f0 = header['Start freq value']
+ dx = header['Delta X-axis']
+ n = header['Number of elements']
+ x = numpy.linspace(f0, f0+dx*n, len(data))
+ y = data.copy()
+
+ import pylab
+ if options.ymode != "lin":
+ minv = min(y[y>0])
+ y[y==0] = minv
+ y = numpy.log10(y)
+ if options.ymode == "db":
+ y = y*10
+ pylab.ylabel('db')
+ pylab.grid()
+ pylab.plot(x, y)
+ pylab.xlabel('frequency')
+ pylab.show()
+
+
+if __name__ == "__main__":
+ main()