Parameter Interactions: Time Gating

The following illustration shows the measurement's extent and resolution in the time and frequency domain. The arrows indicate inversely dependent parameters.

Increasing frequency Span decreases the sample period Dt (which increases the sampling rate). Also, increasing the (main or gate) time length decreases the Resolution Bandwidth (ResBW), which allows more frequency points for better resolution in a spectrum trace.

For more information on how these parameters are related, see Understanding Time and Frequency parameters.

The following are some notes on the interactions between these parameters.

When the time gate is disabled, "time length" means Main Time Length. When the time gate is enabled, "time length" means Gate Length.

When Gate Length is changed, the resolution bandwidth is changed. This means that the resolution bandwidth cannot be explicitly set without changing the gate length.
When the Gate Length or Main Time Length is explicitly set, ResBW-to-span coupling is disabled (set to Fixed) and ResBW Mode is set to Arbitrary. This allows the Gate/Main Time Length to be set to any value supported by the current frequency Span.
Averaging: When RMS or Peak Hold/Continuous Peak Hold averaging is selected, changing trigger delay, gate delay, or gate length will abort any averaging in progress and start a new average. Changing the gate length when time averaging is selected will not abort the average.