Keysight M8121A, User Manual

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Keysight M8121A Arbitrary Waveform Generator User Guide 55
Soft Front Panel 3
• Output - Select the output path.
• DAC Direct Out
• DC Amp Out
• Reduced Noise Floor - Select this option to enable the “Reduced Noise
Floor” feature. When the reduced noise floor feature is enabled, there is
less phase noise in the generated output signal.
The M8121A has a delay adjustment in the module that allows a delay
to be added to a channel’s output signal. Using the delay adjustment, a
user can delay the signal on one channel compared to the signal on the
other channel. One reason for this might be to compensate for
differences in delay caused by different cable lengths. It is also possible
to use the delay adjustment to set an arbitrary delay offset between the
channels.
The delay line used for the delay adjustment adds phase noise to the
output signal. When the reduced noise floor feature is enabled, this
delay line is by-passed so that phase noise is reduced. When reduced
noise floor is enabled, the delay adjustment is not available.
• Amplitude - Sets the amplitude of the output signal.
• CM Offset - Sets the CM (common mode) offset of the output signal
• Diff. Offset - Sets an offset adjustment to compensate for small offset
differences between the normal and complement output.
• Coarse Delay - Specifies the coarse delay portion of the variable delay.
• Fine Delay - Provides a small range of delay that may be added to the
output signal on either channel.The fine delay is not available when
using the Low Phase Noise clock source or when the Reduced Noise
Floor box is checked. The range is dependent on the sample frequency
as follows:
• Sample freq >= 6.25 GSa/s: 0-30 ps
• 2.5 GSa/s <= Sample freq < 6.25 GSa/s: 0-60 ps
• Sample freq < 2.5 GSa/s: 0-150 ps
• Carrier Scale - Sets the carrier amplitude scale for interpolated modes.
The Carrier Scale refers to the amplitude of the carrier signal in
Up-Conversion Mode (Interpolated Mode). IQ data is used to modulate
the carrier signal. An interpolation filter is applied which may result
(depending on the IQ data values) in final DAC values that are outside
the valid range of the DAC. In that case the signal is clipped, and a
warning message is displayed in the Error List Window. When clipping
is not acceptable, the user can set a smaller carrier scale. The default
value for carrier scale guarantees in all cases a signal without clipping.
• Carrier Frequency - Set the carrier frequency for interpolated modes.