NF WF1945B, Instruction Manual, Page: 125 / 188

WF1945B
4-63
4.6 Output waveforms for sweeping and modulation
The setup values for sweeping and modulation are updated every 100 to 252
µ
s. Thus, if the sweep time is
short or the modulation frequency is high, the amount of change for updating increases, leading to marked
discontinuities.
If the sweep function (modulated waves) is
, , or , discontinuities become conspicuous in
some of the stepwise variations.
Since the setup values vary enormously in some of the stepwise variations, discontinuities are generated. If
such discontinuities are removed, the remaining variations have the appearance shown below.
If, as an extreme example, the oscillation frequency is 1 kHz, the sweep time is 4 ms, the start phase is 180
degrees, the stop phase is -180 degrees, and the sweep function is
in the phase sweep, the phase shifts
about 26 degrees every 100
µ
s, producing the following output waveforms. Discontinuities are generated not
only by , but also by , , and .
Since the phase changes at intervals
of 100 to 252
µ
s, discontinuities are
generated
The phase is swept Waveform when swept
Waveform when not swept
Update interval 100 to 252
µ
s