Digital Electronics - Flip-Flops - Discussion

Discussion Forum : Flip-Flops - General Questions (Q.No. 1)
1.
Determine the output frequency for a frequency division circuit that contains 12 flip-flops with an input clock frequency of 20.48 MHz.
10.24 kHz
5 kHz
30.24 kHz
15 kHz
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
35 comments Page 2 of 4.

Mahi said:   1 decade ago
Formula of @Manimegala is correct

Nandan Roy said:   1 decade ago
If N flip flops are connected, then input frequency is divided by 2^n.

So in this problem

20.48 * 10^6 / 2^12 = 5000Hz.

Shivaji said:   1 decade ago
N=2^n;where n= number of flip-flops,N=total number of states of a counter

Sujeet Kumar Layek said:   1 decade ago
We know that a single Flip Flop contains 2 states. For 1 FF frequency is 1/2, for 2 FF frequency is 1/4.

i.e. 1/2^n, where n is the no. of FF.

so for 12 FF, frequency is 1/2^12 = 1/4096.

So, o/p frequency = (i/p frequency)*(1/4096)...

We also called it as a divider ckt.

Anand said:   1 decade ago
Maximum number stored by 12-Flip Flops is 4096.
Freq division =(20.48X10^6)/4096
=5000
Output frequency of the 12 FF's freq divisor is =5KHz

Pushp thakur said:   1 decade ago
12 ff contain 4096 bits and each ff has two states(2^12)
and we've given input frequency i.e.
f=20.48
so the output frequency=input frequency*(1/2^no.of ff)
and the output frequency=20.48*(1/4096)
i.e.o/p frequency=0.005hz(5khz)

Sai said:   1 decade ago
They said 12 flip-flops that mean we require 12 <= 2^n. So we are taking n as 4. Then we know that the output frequency = input frequency/2^n.

So 20.48/2^4=5.

DSingh said:   1 decade ago
The output frequency after each of the flip flop divided by 2.
So after 12 stages the clock frequency becomes

= 20.48*10^6/2^12=~5 KHz.

Hence option B is correct.

Zoro said:   1 decade ago
Input frequency/no.of sequence of count.

Devaraj said:   1 decade ago
1FF are used divide the clock frequency by 2.

12ff divide the frequency by 2^(12).

Given i/p frequency = 20.48MHZ.

Then o/p frequency = (20.48*10^6)/(2^12).

= 5 khz.


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