File format:Tektronix WFM

The Tek WFM format is a special format used by TDS Series scopes. It uses less space than the CSV/Matlab export functions provided.

Header

Bytes	Field
0 - 1	Magic Bytes
2 - 5	Format Code
6	Length of Data, Unsigned integer (so far always 4)
7 - 11	Number of bytes following
12 - 15	Another Magic
16-20	Length of Header + Data (big endian, signed integer)
21 - 28	Vertical Position (Double)
29 - 36	Horizontal Position (Double)
37 - 43	Vertical Zoom (Double)
44 - 51	Horizontal Zoom (Double)
52 - 53	Acquisition Mode (signed integer, currently unknown)
54 - 55	Min Max (unknown)
56 - 63	Duration in seconds (double)
63 - 64	Vertical Coupling (signed integer)
65 - 66	Horizontal Unit (signed integer)
67 - 74	Horizontal time per point (double)
75 - 76	Vertical Unit (signed integer)
77 - 84	Vertical Offset (double)
85 - 92	Vertical Position (double)
93 - 100	Vertical Gain (double)
101 - 105	Record length (unsigned integer)
106 - 107	Trigger Position (signed integer), possibly in points
108 - 109	Header Version (signed integer)
110 - 111	Sampling Density (??) (signed integer)
112 - 113	Burst Segment Length (signed integer)
114 - 115	Waveform Source (signed integer)
116 - 121	3x Video 1 (signed integer)
122 - 129	Video 2 (double)
130 - 131	Video 3 (signed integer)
131 - 163	Preamble (???)

Data

Waveform data. Length of this segment is stored in Record length.

To reconstruct the waveform use the following:

y = data[i] * vertgain / 25 / 256 + vertoffset - vertposition * vertgain
x = (i - (reclength*trigpos/100)) * horizscaleperpoint