Sync This form of oscillator sync is less common. This form is very similar to Hard Sync, with one small difference. In Reversing Soft Sync, rather than resetting to zero, the wave is inverted; that is, its direction is reversed. Reversing Soft Sync is more associated with analog triangle core oscillators than analog sawtooth core oscillators. Threshold or Weak Sync Several kinds of Soft Sync use comparison thresholds: Hard Sync which is disabled when the frequency or amplitude of the follower crosses a user-defined threshold. Hard Sync which is disabled when the frequency of the follower extends too high above or too far below the frequency of the leader. Hard Sync which is disabled when the frequency of the follower is lower than the frequency of the leader. Soft Sync may accurately refer to any of these, depending on the synthesizer or manufacturer in question. Phase Advance 'Sync' The phase of the follower is advanced by some amount when the leader oscillator level crosses some threshold. Used for audio synthesis, this may give an audible effect similar to Soft Sync. Reset Inhibit Sync When the leader oscillator crosses some threshold, the normal reset of the follower is disabled: it will stick at its final level, positive or negative. When the leader crosses back over some threshold, the follower is reset. Overlap Sync In this method, the current wave completes but a new waveform is generated at the sync pulse. The tail of the old wave and the new wave are output summed if they overlap. Digital Implementation Aspects Naive approaches to sync in digital oscillators will result in aliasing. To prevent this, band-limited methods such as additive synthesis, BLIT (Band-Limited Impulse Train) or BLEP (Band-Limited Step) must be adopted to avoid aliasing. In a digital oscillator, best practice is that the follower will not be reset to the identical phase each cycle, but to a phase advanced by an equivalent time to the phase of the leader at the reset. This prevents jitter in the follower frequency and provides truer synchronization. For digital oscillators, Reversing Sync may less frequently generate aliasing. This effect may be naively implemented by measuring the zero axis crossings of the leader oscillator and reversing the slope of the follower oscillator after every other crossing. For digital implementation, note that none of the Threshold or Weak Sync methods actually synthesize the waveform in a way different