210 Keysight CXG, EXG, and MXG X-Series Signal Generators Programming Guide
Creating and Downloading Waveform Files
Understanding Waveform Data
Using E443xB ESG DAC Input Values
Keysight E443xBsignal generator models have a DAC input range that is
different from other Keysight signal generator models. For E443xB models, the
input values are all positive (unsigned) and the data is contained within 14 bits
plus 2 bits for markers. This means that the E443xB DAC has a smaller range:
— 0 = negative full scale output
— 8192 = 0 volts
— 16383 = positive full scale output
Although X-Series signal generators use signed input values, they accept
unsigned data created for the E443xB and convert it to the proper DAC values.
To download an E443xB files to an X-Series signal generator, use the same
command syntax as for the E443xB models. For more information on
downloading E443xB files, see “Downloading E443xB Signal Generator Files”
on page 251.
Scaling DAC Values
The signal generator uses an interpolation algorithm (sampling between the
I/Q data points) when reconstructing the waveform. For common waveforms,
this interpolation can cause overshoot, which may exceed the limits of the
signal process path’s internal number representation, causing arithmatic
overload. This will be reported as a data path overload error. Because of the
interpolation, the error condition can occur even when all the I and Q values
are within the DAC input range. To avoid the DAC over–range problem, you
must scale (reduce) the I and Q input values, so that any overshoot remains
within the DAC range.
DAC over–range
No over–range
Interpolation
Interpolation
768
67
Scaling effect
alue
Whenever you interchange files between signal generator models, ensure
that all scaling is adequate for that signal generator’s waveform.
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