Command Groups
TDS3000, TDS3000B, and TDS3000C Series Programmer Manual
2-39
Waveform Commands
Waveform commands let you transfer waveform data points to and from the
oscilloscope. Waveform data points are a collection of values that define a
waveform. One data value usually represents one data point in the waveform
record. When working with peak detect or envelope waveforms, each data value
is either the min or max of a min/max pair. Before you transfer waveform data,
you must specify the data format, record length, and waveform source.
Table 2--28 on page 2--42 lists these commands.
Acquired waveform data uses 9 or more bits to represent each data point. The
number of bits used depends on the acquisition mode specified when you
acquired the data. Data acquired in SAMple, ENVelope, or PEAKdetect mode
uses 9 bits per waveform data point. Data acquired in AVErage mode uses up to
14 bits per point. For more information on the acquisition modes see the
ACQuire: MODe command on page 2--45.
The DATa:WIDth command lets you specify the number of bytes per data point
when transferring data to and from the oscilloscope. If you specify two bytes for
data, the acquired waveform data is left-shifted to be left-justified in the 16-bit
(2 byte) data quantity. If you specify one byte for data, the least significant bit(s)
are ignored.
The oscilloscope can transfer waveform data in either ASCII or binary format.
You specify the format with the DATa:ENCdg command.
ASCII data — is represented by signed integer values. The range of the values
depends on the byte width specified. One byte wide data ranges from --128 to
127. Two byte wide data ranges from --32768 to 32767.
Each data value requires two to seven characters. This includes one to five
characters to represent the value, another character, if the value is negative, to
represent a minus sign, and a comma to separate the data points.
An example ASCII waveform data string may look like this:
CURVE<space>-110,-109,-110,-110,-109,-107,-109,-107,
-106,-105,-103,-100,-97,-90,-84,-80
Use ASCII to obtain more human readable and easier to format output than
binary. However, it may require more bytes to send the same values with ASCII
than it does with binary. This may reduce transmission speeds.
Binary data — can be represented by signed integer or positive integer values.
The range of the values depends on the byte width specified. When the byte
width is one, signed integer data ranges from --128 to 127, and positive integer
Waveform Data Formats
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