Up Counter Question - Getting 10MHz Instead of 20MHz

[amninder15]

Hi

I got this question on midterm. the correct answer is 20 MHz.

But I am getting 10 MHz. I attached a text file which shows all the work I done.

Can someone please explain this question and tell me where I am doing it wrong.

Thanks

 

[collinsmark]

Hi

I got this question on midterm. the correct answer is 20 MHz.

But I am getting 10 MHz. I attached a text file which shows all the work I done.

Can someone please explain this question and tell me where I am doing it wrong.

Thanks

Therefore the state diagram is: 1010 --> 1011 --> 1100 --> 0010 --> 0011 --> 0100
and then it repeats

Your state diagram, and sequence are correct.

So according to me since this counter has 6 different states thus the frequency is 60/6 = 10 MHz.

Look at the problem statement once again (and Figure 12). You need to calculate the frequency of signal z. (The signal z is the same thing as Q₁.) How many periods does signal z have in one complete sequence?

 

[amninder15]

so now if I was to write Z I get
1 1 0 1 1 0

therefore Z is repeating 110 thus,

60/3 gives 20 MHz

am I on right track?

 

[collinsmark]

so now if I was to write Z I get
1 1 0 1 1 0

therefore Z is repeating 110 thus,

60/3 gives 20 MHz

am I on right track?

Yes, you are absolutely on the right track. But you'll need to be a little more detailed about where that '3' came from. (I think you already have it, but you should be prepared spell it out for the sake of your instructor).

There are 6 clock cycles per sequence (as you have already figured out in your original post). How many periods of z exist per sequence? How many clock cycles exist in one period of z? And thus, what's the frequency of z?