Agilent Spectrum Analysis Basics - Agilent Technologies
Agilent Spectrum Analysis Basics - Agilent Technologies
Agilent Spectrum Analysis Basics - Agilent Technologies
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Figure 2-32a. Video filtering<br />
Figure 2-32b. Trace averaging<br />
Figure 2-32. Video filtering and trace averaging yield different results on FM broadcast signal<br />
Time gating<br />
Time-gated spectrum analysis allows you to obtain spectral information<br />
about signals occupying the same part of the frequency spectrum that are<br />
separated in the time domain. Using an external trigger signal to coordinate<br />
the separation of these signals, you can perform the following operations:<br />
• Measure any one of several signals separated in time; for example, you<br />
can separate the spectra of two radios time-sharing a single frequency<br />
• Measure the spectrum of a signal in one time slot of a TDMA system<br />
• Exclude the spectrum of interfering signals, such as periodic pulse edge<br />
transients that exist for only a limited time<br />
Why time gating is needed<br />
Traditional frequency-domain spectrum analysis provides only limited<br />
information for certain signals. Examples of these difficult-to-analyze signals<br />
include the following signal types:<br />
• Pulsed RF<br />
• Time multiplexed<br />
• Time domain multiple access (TDMA)<br />
• Interleaved or intermittent<br />
• Burst modulated<br />
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