Rohde & Schwarz AM 300, Руководство по эксплуатации

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R&S AM300 Arbitrary and Function Generator
Operating manual, 02/2005 6-99 E-1007.9922.12
Uncertainty of a
start phase depends
on the frequency The uncertainty of a signal’s start phase depends on the frequency that has
been set. This restriction applies not to sine waveforms, since you can
clearly reconstruct the phase also at higher frequencies due to the sampling
theorem. With all other waveforms such as square, triangular, ramp,
exponential and arbitrary, you must pay attention to the effect of the
frequency on the uncertainty of the start phase. This is due to the decreasing
number of points across the frequency that are available to generate the
curve. In the worst case, only two points are available, resulting in an
uncertainty of 180 °.
Therefore, the standard waveforms square, triangular and exponential in the
R&S AM300 are restricted to a max. frequency of 500 kHz. The uncertainty
arising at the max. frequency is 2.8 °. However, if these waveforms are
generated by means of Waveform Composer and loaded as arbitrary curves
into the R&S AM300, it is possible to set also higher frequencies. The
following diagram shows the max. uncertainty of the phase as a function of
the frequency that has been set.
Phase resolution vs.
output frequency for
non-sinusoidal signal
0,000001
0,00001
0,0001
0,001
0,01
0,1
1
10
100
0,0001 0,001 0,01 0,1 1 10 100 1000 10000 100000
Frequency [kHz]
Phase resolution [deg.]