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Agilent E1441A Application Information 47
Chapter 2
frequencies. Since these signals are non-repetitive, all frequency
components cannot be harmonically related to the window length. You
should be careful in these situations to minimize end-point discontinuities
and spectral leakage.
Creating and Storing an
Arbitrary Waveform
The following is an overview of the steps required to download and output
an arbitrary waveform. The commands used for arbitrary waveforms are
listed on page
Chapter 2, “Application Programs”, contains an example program which
shows the use of arbitrary waveforms. You may find it useful to refer to the
program after reading the following section in this chapter.
1. Select the waveform frequency, amplitude, and offset.
Use the
APPLy command or the equivalent FREQ, VOLT, and VOLT:OFFS
commands to select the frequency, amplitude, and offset of the arbitrary
waveform. Because the APPLy command also changes duty cycle,
modulation type, trigger source, and trigger slope, you must place the
APPLy command first in any sequence of configuration commands.
2. Download the data points into volatile memory.
You can download between 8 and 16,000 points per waveform.
The waveform can be downloaded as floating-point values or binary integer
values. Use the
DATA VOLATILE command to download floating-point
values between -1 and +1. Use the
DATA:DAC VOLATILE command to
download binary integer values between -2047 and +2047.
To ensure that binary data is downloaded properly, you must select the order
in which the bytes are downloaded using the
FORM:BORD command.
3. Copy the arbitrary waveform to non-volatile memory.
You can output the arbitrary waveform directly from volatile memory (as
described in step 2) or you can copy the waveform to non-volatile memory.
Use the
DATA:COPY command to copy the waveform to non-volatile
memory.
4. Select the arbitrary waveform to output.
You can select one of the five built-in arbitrary waveforms, one of four
user-defined waveforms, or the waveform currently downloaded to volatile
memory. Use the
FUNC:USER command to select the waveform.
5. Output the currently selected arbitrary waveform.
Use the
FUNC:SHAP USER command to output the waveform previously
selected with the
FUNC:USER command.