1) We can create an oscillator using an odd no: of nand,not etc.....(since the frequency depends on the propagation delay, definitely we can achieve high clock frequency, so can we replace the crystal oscillator in our computer by this clock ?
2) What is the exact definition of an amplifier ?
3) What is metastability in flip-flopes ?
4) is there something called the 'zero hold time' flip-flop ?

 

1. The purpose of the crystal in the oscillator circuit is for frequency stability. Substituting 3 - 5 inverter elements will oscillate, but things like temperature, power supply variation, other circuit operation, and just about any other variable will have some effect on the frequency. This is not a way to achieve stability.
2. Google
3. They can be in one of two states, or in a transition from one to the other.
4. If I understand this as meaning that the set or reset state would not be latched, then what would be the purpose of that logic element?

 

4) is there something called the 'zero hold time' flip-flop ?

Are you confusing this with zero order hold flip-flops?

Zero-order hold and zero hold time are very different concepts.

Dave

 

1) We can create an oscillator using an odd no: of nand,not etc.....(since the frequency depends on the propagation delay, definitely we can achieve high clock frequency, so can we replace the crystal oscillator in our computer by this clock ?
...QUOTE]

You can create a clock generator using three not gates. This is a series resonant clock generator (as oposite to paralel resonant clock oscillator, because the NAND gates, working as 180º out-of-phase amplifiers, are in series).
Also you can create a paralel resonant oscillator, but you will have more problems.

Read this: ftp://download.intel.com/design/mcs51/applnots/23065901.pdf