Fluke DDS Function Generator 271, User Manual

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271
Users Manual
11-2
Introduction
The hop facility allows up to 16 different waveforms to be output in sequence at a rate
determined by either the internal timer, an external trigger, a remote command or by
pressing the
MAN/SYNC key. Each waveform can be set to any wave shape, frequency,
amplitude and offset; symmetry is the same for every step in the sequence and is defined
on the main menu before Hop is selected. Frequency-only changes are phase-continuous.
Hop is both edited and controlled from the hop menu, accessed by pressing the EDIT key
followed by HOP (the numeric 5 key). Return to the main menu is by pressing
ESCAPE .
Setting each Waveform Step
The hop menu is shown below. With the
HOP
field set to
HOP:OFF
the edit cursor
can be moved around all the editable fields using the
FIELD
and
DIGIT
keys in the
standard way.
HOP:OFF n=01 01.000s
FREQ=10.00000kHz
VhiZ =+20.0 Vpp SINE
DC=+0.00mV LAST=01
The 16 steps are numbered 00 to 15. The step to be edited is selected with the edit cursor
in the
n=
field using direct keyboard entries, followed by
ENTER
, or the rotary
control.
For each step the frequency, amplitude and offset are set up, having positioned the cursor
in the appropriate field, exactly as for the main menu; the cursor can be moved directly to
the fields of interest by pressing the
FREQ/PER
,
AMPL
, or
DC OFFSET
keys as
appropriate. For further information see the Main Generator Parameters section in
chapter 5, Main Generator Operations earlier in this manual.
The other parameters of the main menu, symmetry and output impedance, are set on that
menu and are the same for every hop waveform.
The wave shape for each step is selected directly with the standard function keys or with
the cursor in the edit field to the right of the amplitude display. The
DIGIT
keys or rotary
control can be used to step through each choice in turn; the corresponding lamp beside
the function key lights to confirm the selection. The currently loaded
STAIR
case and
ARB
itrary waveforms are also included in the selection sequence (between
-RAMP
and
SINE
) and their lamps also light when they are selected.
All parameters can be copied from one step to the next step by entering the new step in
the
n=
field and pressing
RECALL
; the differences in the new step can then be entered
as described above. This provides a quick means of creating new steps when only one or
two parameters change.
Defining the Sequence and Timing
All 16 steps always contain a set-up, even if this is only the default setting. When set to
run the hop sequence will start at step 00 and execute steps in chronological order up to
the step number defined in the
LAST=
field, after which it will go back to step 00 and
start again. The desired sequence should therefore be set starting at step 00 and the
LAST=
field should be set to the last valid step number.
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