Time-Gated Spectral Analysis with X-Series Signal Analyzers
애플리케이션 노트
What is Time Gating?
Time gating allows you to measure the spectrum of a periodic signal during a specific portion of time, typically the on-time of the bursted signal. A trigger is used to synchronize when the burst occurs. In many cases the spectral components that otherwise would contribute to the pulse’s rising and falling edge will mask spectral components that contribute to the spectrum of the pulse during its on time. Gating is also useful for applied spectral measurements such as channel power, adjacent channel power, and spectral emission mask measurements of a modulated signal that is bursted in the time domain.
When making measurements with time gating, you need four basic items:
- An externally or internally supplied gate trigger signal
- A gate control or trigger mode (edge or level)
- A gate delay setting (determines how long after the trigger signal the gate becomes active)
- A gate length setting (determines how long the gate is on)
We will discuss this further with examples to illustrate effective time-gated spectral analysis.