Control System Toolbox Function Reference

allmargin

Compute all crossover frequencies and corresponding stability margins

Syntax

S = allmargin(sys)

Description

allmargin computes the gain, phase, and delay margins and the corresponding crossover frequencies of the SISO open-loop model sys. allmargin is applicable to any SISO model, including models with delays.

The output S is a structure with the following fields:

• GMFrequency -- All -180 degree crossover frequencies (in rad/sec)
• GainMargin -- Corresponding gain margins, defined as 1/G where G is the gain at crossover
• PMFrequency -- All 0 dB crossover frequencies in rad/sec
• PhaseMargin -- Corresponding phase margins in degrees
• DMFrequency and DelayMargin -- Critical frequencies and the corresponding delay margins. Delay margins are given in seconds for continuous-time systems and multiples of the sample time for discrete-time systems.
• Stable -- 1 if the nominal closed-loop system is stable, 0 otherwise.

See Also
ltimodels   Help on LTI models

ltiview     LTI system viewer

margin      Gain and phase margins for SISO open-loop systems

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