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1-7-4. Data file
16-bit data converted from analog to digital is recorded as 2-byte integer values from -32768 to +32767 while 24-bit
converted data is recorded as 4-byte integer values from -8388608 to +8388607. Negative numbers are shown using
two’s-complement notation.
The byte order is from the lowest to the highest (Intel format).
The data order is from the first sampling channel to the second sampling channel and so on until the last sampling
channel. This order is called the INTERLACED format, and the format name is recorded in STORAGE_MODE in the
header file.
The structure of a data file is as follows. In this document, a collection of data as shown in the example is called a
“scan”. A data file is made of repeated scans.
Example of data for one scan recorded at 6kHz sampling frequency
Data order
CH1
CH2
1/6000
CH3
CH4
1-7-4-1. Converting data to physical quantities
16-bit data converted from analog to digital is recorded as integer values from -32768 to +32767 and the value would
be ±25000 when the input is ±100% in the input range settings. 24-bit converted data is recorded as integer values
from -8388608 to +8388607 and the value would be ±6400000 when the input is ±100% in the input range settings.
The input value is obtained from the following formula:
Input value = (A/D conversion value of the data file) × SLOPE + Y_OFFSET
o
See “Explanations of header file” on page 8 for information about SLOPE and Y_OFFSET.
1-7-5. Header file
Header files are ASCII-format text files containing information such as recording conditions.
In a header file, each recording-condition entry is written on 1 line, with parameters separated by a comma (,). An
example of a header file is shown as follows.
Example of header file
DATASET LX1K_001
VERSION 1
SERIES CH1_PA AMP CH 1,CH2_PA AMP CH 2,CH3_PA AMP CH 3,CH4_PA AMP CH 4
DATE 02-27-2019
TIME 14:05:00.00
RATE 48000
VERT_UNITS V,V,V,V
HORZ_UNITS Sec
COMMENT LX-1000
NUM_SERIES 4
STORAGE_MODE INTERLACED
FILE_TYPE LONG
SLOPE 1.562600e-07,1.562600e-07,1.562600e-07,1.562600e-07
X_OFFSET 0.0
Y_OFFSET 0.000,0.000,0.000,0.000
NUM_SAMPS 1440000
1. Introduction
Continued on the next page
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