This means that there might not be a reset pulse supplied to the core of the VLSI.
2.
Overlap sync is primarily a digital technique with simple implementation, such as used in FOF ( An analog implementation could be a highly damped sine oscillator excited by the reset pulse .)
3.
When the power supply ramp is rapid, the R and C values can be calculated so that the time to reach the switching threshold of the schmitt trigger is enough to apply a long enough reset pulse.