#digitalCircuit

Question

how it works??

Comments

Give 0 at Vo then check after how much time it come back to 0 again. Or give 1

By drawing Timing diagram.

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thanks got it !

can you ans these 

https://gateoverflow.in/90103/%40​digitalcircuit

https://gateoverflow.in/90240/%23​digitalcircuit

Answer 1

Actually here we can see that the inverters are cascaded i.e. placed once after the another..Hence the propogation delay of each gate adds up..

So overall delay =  5 * 100 ps

                        =  500 ps

Hence fundamental frequency which drives the oscillator =  1 / delay

                                                                                   =  1 / (500 * 10^-12) Hz

                                                                                   =  1000 / 500 GHz

                                                                                   =   2 GHz

Hence D) is the correct answer.. 

Comments

ans given as 1Ghz ...in solution saying ...oscillator( 1 to 0 and o to 1) or ( 0 to 1 and 1 to 0) is consider as 1 cycle which takes 1000 picosec...confused??

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Yes frequency of ring oscillator = 1 / 2*t*n = 1 / 2 * 10^-12 * 500 = 1GHZ.

you can find formula here.

https://en.wikipedia.org/wiki/Ring_oscillator

Similar:https://gateoverflow.in/66433/digital-logic-propagation-delay

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@Habibkhan @sh!va @Prabhanjan_1

try this one also...im stuck ...

https://gateoverflow.in/90103/%40​digitalcircuit

https://gateoverflow.in/90240/%23​digitalcircuit

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are these in syllabus??

Answer 2

Imagine the circuit output is 0 at beginning.. First not gate gets 0 as input. Each not gate will gets input as 0-> 1 -> 0 -> 1 ->0

Finally last not gate will give 1 as output..which is given as input of first not gate

Now sequence will be 1 ->0->1->0->1->0

So output oscillates between 0 and 1

. Total delay = 5*1 = 5pico seconds Frequency = 1/5 picosec = 2 GHz

Comments

ans given as 1Ghz ...in solution saying ...oscillator( 1 to 0 and o to 1) or ( 0 to 1 and 1 to 0) is consider as 1 cycle which takes 1000 picosec...confused??