Range Resolution - Agilent Technologies 8753ET User Manual

discontinuity shadowing the response of a smaller discontinuity, all act to degrade the
effective response resolution.
Figure 3-24 illustrates the effects of response resolution. The solid line shows the actual
reflection measurement of two approximately equal discontinuities (the input and output
of an SMA barrel). The dashed line shows the approximate effect of each discontinuity, if
they could be measured separately.
Figure 3-24 Response Resolution
While increasing the frequency span increases the response resolution, keep the following
points in mind:
• The time domain response noise floor is directly related to the frequency domain data
noise floor. Because of this, if the frequency domain data points are taken at or below
the measurement noise floor, the time domain measurement noise floor is degraded.
• The time domain measurement is an average of the response over the frequency range
of the measurement. If the frequency domain data is measured out-of-band, the time
domain measurement is also the out-of-band response.
You may (with these limitations in mind) choose to use a frequency span that is wider than
the test device bandwidth to achieve better resolution.

Range Resolution

Time domain range resolution is defined as the ability to locate a single response in time.
If only one response is present, range resolution is a measure of how closely you can
pinpoint the peak of that response. The range resolution is equal to the digital resolution of
the display, which is the time domain span divided by the number of points on the display.
To get the maximum range resolution, center the response on the display and reduce the
time domain span. The range resolution is always much finer than the response resolution
(see Figure 3-25).
Making Time Domain Measurements
Resolution
3-33