Fluke DDS Function Generator 271, Руководство пользователя

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Main Generator Operation
Main Generator Parameters
5
5-3
Lastly, with the edit cursor in the units field, pressing the
DIGIT
keys or turning the
rotary control will change the value in decade increments; the decimal point will move
and/or the units will change as appropriate. Full 7-digit precision is maintained as the
value is decremented until the 0 . 1 mHz resolution limit of the instrument is reached;
values which would have had least significant bits <0 . 1 mHz are truncated with further
decrements and the precision is consequently lost when the number is incremented again.
Output Level
The second line of the main menu permits the output level to be set in terms of
VhiZ
(open circuit voltage) or
V
(potential difference into a matched load) or
dBm
(referenced to the specified source impedance). Both
VhiZ
and
V
can be set in terms
of peak-to-peak volts (
Vpp
) or r.m.s. volts (
Vrms
).
Note that in both cases the true peak-to-peak or r.m.s. values are shown for the selected
waveform, even an arbitrary waveform. However, in the case of
Vrms
the dc offset
(see next section) is ignored in the calculation and must be taken into consideration by
the user if it is non-zero.
FREQ=10.00000kHz
VhiZ=+20.0 Vpp 50
Ω
DC=+0.00mV (+0.00mV)
SYM=50.0% (50.0%)
The desired form of the output level display can be selected while the edit cursor is in the
parameter name field by stepping through all the options with the
DIGIT
keys or the
rotary control; bring the cursor to the parameter name field first, if necessary, by pressing
AMPL
or by using the
FIELD
keys.
With the appropriate parameter form selected, the value is entered as a number followed
by units, for example 100 mV can be entered as
1
,
0
,
0
,
mV
or
.
,
1
,
V
, etc. The firmware
acts intelligently in certain situations; for example, even if
VhiZ
or
V
is the selected
parameter form, entering a number followed by the
dBm
key will cause the number to be
entered as dBm. Similarly, with
dBm
as the selected parameter form, entering a number
followed by
V
or
mV
will cause the number to be entered as Vrms.
0 dBm is 1 mW into the specified impedance; low signal levels are specified by using the
+/-
key to enter negative dBm. (The
+/-
key is also used for output inversion, as described
beow).
Moving the edit cursor to the numeric field permits the set value to be varied by the
rotary control in steps determined by the cursor position within the field. The
FIELD
keys move the cursor to the field and the
DIGIT
keys move it within the field.
Moving the edit cursor to the units field permits the numeric value to be changed in
decade steps by the
DIGIT
keys or rotary control; the decimal point will move and/or the
units will change as appropriate. Further increments are inhibited if the next decade step
would have taken take the value above the maximum level or below the minimum level.
Decade stepping with the
DIGIT
keys or rotary control is also inhibited when the level is
displayed in
dBm
.
Wherever the cursor is positioned on the second line of the display, alternate presses of
the
+/-
key will invert the
MAIN OUT
output. If the dc offset is non-zero, the signal is
inverted about the offset. The one exception to this is if the output level is specified in
dBm; since low signals are specified in -dBm, the
-
sign is interpreted as part of a new
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