To initiate oscillation, the loop gain of the oscillator must be ______ unity

Concept:

Barkhausen Criterion 'or' Conditions for Oscillation:

The circuit will oscillate when two conditions, called Barkhausen’s criteria are met. These two conditions are:

• The loop gain must be unity or greater, i.e. |Aβ| ≥ 1

​          A = Amplifier gain and β = Feedback gain

• The feedback signal feeding back at the input must be phase-shifted by 360° (which is the same as zero degrees). In most of the circuits, an inverting amplifier is used to produce 180° phase-shift and an additional 180° phase shift is provided by the feedback network.