Agilent Technologies Infiniium 90000 Q-Series, Programmer'S Manual

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78 Agilent Infiniium 90000 Series Oscilloscopes Programmer's Reference
3
Introduction to Programming
Using the DIGITIZE Command
The DIGITIZE command is a macro that captures data using the
acquisition (ACQUIRE) subsystem. When the digitize process is complete,
the acquisition is stopped. You can measure the captured data by using
the oscilloscope or by transferring the data to a computer for further
analysis. The captured data consists of two parts: the preamble and the
waveform data record.
After changing the oscilloscope configuration, the waveform buffers are
cleared. Before doing a measurement, you should send the DIGITIZE
command to ensure new data has been collected.
You can send the DIGITIZE command with no parameters for a higher
throughput. Refer to the DIGITIZE command in
Chapter 27 , “Root Level
Commands,” starting on page 703 for details.
When the DIGITIZE command is sent to an oscilloscope, the specified
channel's waveform is digitized using the current ACQUIRE parameters.
Before sending the :WAVEFORM:DATA? query to download waveform data
to your computer, you should specify the WAVEFORM parameters.
The number of data points comprising a waveform varies according to the
number requested in the ACQUIRE subsystem. The ACQUIRE subsystem
determines the number of data points, type of acquisition, and number of
averages used by the DIGITIZE command. This lets you specify exactly
what the digitized information contains. The following program example
shows a typical setup:
myScope.WriteString ":SYSTEM:HEADER OFF"
myScope.WriteString ":ACQUIRE:MODE RTIME"
myScope.WriteString ":ACQUIRE:COMPLETE 100"
myScope.WriteString ":WAVEFORM:SOURCE CHANNEL1"
myScope.WriteString ":WAVEFORM:FORMAT BYTE"
myScope.WriteString ":ACQUIRE:COUNT 8"
myScope.WriteString ":ACQUIRE:POINTS 500"
myScope.WriteString ":DIGITIZE CHANNEL1"
myScope.WriteString ":WAVEFORM:DATA?"
This setup places the oscilloscope into the real time sampling mode using
eight averages. This means that when the DIGITIZE command is received,
the command will execute until the waveform has been averaged at least
eight times.
After receiving the :WAVEFORM:DATA? query, the oscilloscope will start
downloading the waveform information.
Digitized waveforms are passed from the oscilloscope to the computer by
sending a numerical representation of each digitized point. The format of
the numerical representation is controlled by using the
:WAVEFORM:FORMAT command and may be selected as BYTE, WORD, or
ASCII.