e/Phase margin

Information
has gloss	eng: In electronic amplifiers, phase margin (PM) is the difference between the phase, measured in degrees, of an amplifier's output signal (relative to its input) and 180°, as a function of frequency. The PM is taken as positive at frequencies below where the open-loop phase first crosses 180°, i.e. the signal becomes inverted, or antiphase; it is negative beyond. In negative feedback, a negative PM at a frequency where the loop gain exceeds unity guarantees instability, thus positive PM is a "safety margin" that ensures proper operation of an amplifier and, more generally, active filters, under various loads. In its simplest form, involving ideal negative feedback voltage amplifiers with non-reactive feedback, the phase margin is measured at the frequency where the open loop voltage gain of the amplifier equals the desired closed loop DC voltage gain.
lexicalization	eng: phase margin
instance of	c/Electrical parameters