Frequency Range And Points; Stimulus (Mode); Set Frequency Lowpass; Start/Stop Time - Agilent Technologies FieldFox N9912A User Manual

 When finished changing ALL settings, press

Frequency Range and Points

Like CAT mode, all Time Domain measurements are made in the frequency
domain and, using Inverse Fourier Transform (IFT), time is calculated. Select the
frequency range from which Time Domain measurements are calculated.
Increasing the data points will improve measurement resolution. However, more
data points will usually result in slower sweep updates.
Set frequency range and points before selecting Stimulus Mode.

Stimulus (Mode)

There are three variations on how the Time Domain transform algorithm is
applied to the frequency domain measurement. Each method has a unique
application.


In both Lowpass modes, frequencies down to DC and negative frequencies are
extrapolated. Therefore, when either Lowpass mode is selected, Set Freq.Low
Pass is automatically applied to adjust the start frequency. Learn more about Set
Frequency Lowpass below.
When the Start Frequency or resolution is changed AFTER selecting a Lowpass
mode, then Stimulus mode is set to Band Pass and Transform is disabled.


Set Frequency Lowpass

NOTE This setting is made automatically when either Lowpass mode is selected.
USE ONLY IN LOW PASS MODES. When this setting is made, the start frequency
is adjusted to be harmonics of the start frequency. Start frequency is computed
by the following formula:
Low Pass Start Frequency = Stop Frequency / Number of points.

Start/Stop Time

The following settings adjust the display resolution, allowing you to zoom IN or
OUT on a response. When the start or stop time is updated, they may be
automatically adjusted to limit the display to one alias-free response on either
side of zero time.
Time Domain - Option 010
Left The Settings table is shown to the left of the trace window.
o
Bottom The Settings table is shown below the trace window.
o
Lowpass Impulse
- Highest resolution. Most useful for seeing small responses
in devices that pass low frequencies, such as cables.
Lowpass Step
- Easiest to identify inductive and capacitive discontinuities in
devices that pass low frequencies such as cables.
Band pass- Easiest method - can be used with any frequency sweep. Most
useful for measuring band limited devices such as filters and DC blocked
cables. This mode does NOT show capacitive and inductive reactance. For the
same frequency span and number of points, band pass mode has twice the
impulse width, which hides closely spaced responses degrading the response
resolution.
Done
to save your settings.
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