Agilent Technologies 8753ET User Manual page 212

Making Time Domain Measurements
Transforming CW Time Measurements into the Frequency Domain
Figure 3-19 Separating the Amplitude and Phase Components of Test-Device-Induced Modulation
Forward Transform Range
In the forward transform (from CW time to the frequency domain), range is defined as the frequency span
that can be displayed before aliasing occurs, and is similar to range as defined for time domain
measurements. In the range formula, substitute time span for frequency span.

Number of points
Range
= ----------------------------------------------------------- -
time span

201 1 –

Range = ------------------------
3 –

200 10

Range =
1000 Hertz
For the example, a 201 point CW time measurement made over a 200 ms time span, choose a span of 1 kHz
or less on either side of the center frequency (see
3-24
– 1


Figure 3-20). That is, choose a total span of 2 kHz or less.