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SECTION 3
Operation
lowed
rate ranges from 0.001msec (lpsec) to
2,999.9sec. You can also set the rate as a fre-
quency, in which
case the allowed
frequency
range is from 0.0004Hz to lOOO.OkHz. When the
rate is programmed
as a frequency,
the actual
rate is set by rounding
the reciprocal of the given
frequency to the value closest to the allowed pe-
riod (the reciprocal is truncated to eliminate the
portion below the resoluiion).
As a result, setting
the rate as a frequency may result in significant
errors when the reciprocal
of the frequency
is
very small. For example, entering frequencies of
either
lOOO.OkHz or 6OO.OOkHz results
in a
O.OOlmsec period.
BLJRST CYCLE (Number
of
burst cycles)
[MODIFY]
KXZEI
The BURST CYCLE key allows you to program
the number
of burst cycles, which
defines the
number
of waveform
cycles generated in the
burst oscillation
mode. The allowed range of set-
tings is from 1 cycle to 65,536 cycles. To use burst
oscillation,
select the burst oscillation
mode with
the MODE key.
PHASE Wart/stop phase)
[MODIFY]
[SIZE]
The PHASE key allows
programming
of the
start/stop
phase setting for the burst or gate os-
cillation modes. The allowed phase range is from
-360.0" to 360.0" with 0.1" resolution.
When the Model 3930A is used with the optional
Model 3933A Phase Shifter to form a multiphase
oscillator, the phase setting is the phase offset for
the Model 3933A.
NOTE
In the burst or gate oscillation
modes, oscilla-
tion may be unstable if the next trigger is ap-
plied at approximately
the same time the pre-
vious oscillation
cycle ends. In this situation,
set the Model 3930A temporarily
to another
oscillation
mode, then return it to the desired
mode. Doing so willrestorenormal
operation.
SWEEP (Frequency sweep keys)
The various SWEEP keys are used to program
sweep functions
such as start and stop fre-
quency, center and span frequencies, and sweep
3-4
function and sweep time. The paragraphs below
summarize the operation of these keys. Refer to
the specifications
located in Appendix
B for de-
tails on the sweep range.
Note that frequency parameters can also be set
using waveform
period. See the discussion
on
the ENTRY keys (
0
5
) for information
on fre-
quency and period setting.
START FREQ (Start frequency)
[MODIFY]
[SIZE1
The START FKEQ key allows you to set the start
frequency of the frequency sweep. You can spec-
ify a start frequency that is either higher or lower
than the stop frequency.
The relationship
be-
tween the start and stop frequency values deter-
mines the sweep direction. If the start frequency
is higher than the stop frequency, the sweep will
be performed
in a descending
direction.
If the
start frequency is lower than the stop frequency,
the sweep will be performed in the ascending di-
ECtiOll.
If the start frequency
is changed, the sweep
range will be determined
by the new start fre-
quency and the current stop frequency.
STOP FREQ (Stop frequency)
[MODIFY]
[SIZE]
The STOP FREQ key allows you to set the stop
frequency of the frequency sweep. You can spec-
ify a stop frequency that is either higher or lower
than the start frequency. If the stop frequency is
higher than the start frequency,
the sweep will
be performed in ascending order. If the stop fre-
quency is lower than the start frequency,
the
sweep will be performed in descending order.
Ifthestopfrequencyischanged,thesweeprange
will be determined
by the new stop frequency
and the current start frequency.
CTR (Center frequency)
[MODIFY]
[SIZE]
The CTR key allows setting of the center fre-
quency of the frequency
sweep. The center fre-
quency is specified as the center frequency
for
the linear scale, and is not the sweep time basis
center frequency for LOG sweep.
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