Tektronix CSA7404B, Руководство пользователя

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Creating and Using Math Waveforms
CSA7000B Series & TDS7000B Series Instruments User Manual
3- 183
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Multiple analyzer control locks: Up to four spectral analyzers may be used
simultaneously. They may all be assigned to different gates on the same
source waveform or to different channel sources. The controls of Math1 and
Math2 may be locked and the controls of Math3 and Math4 may be locked;
that is, turning a control on one analyzer changes the control on the other
analyzer to the same value. Other combinations of locking, including all four
analyzers, are available using GPIB commands.
The same exclusions for math waveforms apply to spectral math waveforms. In
addition, sources for spectral math waveforms must be channel waveforms.
Read the following topics; they provide details that can help you create the
spectral waveform that best supports your data-analysis tasks.
The spectral analyzer contains five primary control categories. These are shown
in Table 3--12.
Table 3- 12: Spectral analyzer controls
Time controls Gate controls Frequency controls Magnitude controls Phase controls
Source Position Center dB, dBm linear, real
imaginary degrees, radians, group
delay
Duration, record length Duration Span Ref level Zero threshold
Duration, sample rate Window Resolution bandwidth Ref level offset Phase Unwrap
Resolution
Using the time controls. The operation of the time domain controls for the
spectral analyzer is summarized by the following rules:
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Duration selects the time from the beginning to the end of the acquired
waveform. You may set duration using the record length control or the
sample rate control.
H
Resolution determines the time between samples. Duration is kept constant
as resolution is changed. Therefore, the Resolution control affects both the
sample rate and the record length simultaneously.
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Most often, you will want to use a short record length because long record
lengths can slow instrument response. However, long record lengths lower
the noise relative to the signal and increase the frequency resolution for the
spectral math waveform. More important, they might be needed to capture
the waveform feature you want to include in the waveform.
Examples of how duration and resolution affect the acquired waveform are
shown in Figure 3--47.
Using Spectral Math
Controls