# Iterative Circuit

1. Feb 16, 2015

### Max0007

1. The problem statement, all variables and given/known data
I have to detect a pattern (11011) once this detected I put a 1 in my ouput Z to 1 to the 0 of the pattern.
Example :
11011001.....
00100000...
2. Relevant equations

3. The attempt at a solution

#### Attached Files:

• ###### 20150216_210802.jpg
File size:
32.4 KB
Views:
65
2. Feb 16, 2015

### lewando

How is your input being presented to your detector? As a time-sequence of bits? Or all at once, as a group of bits (like a byte)?

3. Feb 16, 2015

### Max0007

Well I would have 16 cells like the one I draw. And my circuit would receive a sequence of 16 bits at a time.

4. Feb 16, 2015

### lewando

Sorry, I am having trouble reading the image and so I don't understand your approach. Okay, so correct me if I am wrong: a 16-bit word is applied to the input of the detector (a functional block with 16 inputs and 16 outputs), then detector outputs a 16-bit word with 1's in the correct place. Is that right?

5. Feb 16, 2015

### Max0007

Yes

6. Feb 16, 2015

### Max0007

Better now ?

7. Feb 16, 2015

### lewando

Thanks for the detailed images, much more readable.

First off, I see a table with xi and yi, then a box with xi as input and zi as output. Is zi the same as yi?
When I see something like that (xi), it makes me think of a stream of bits with an index i that is forever increasing as the stream continues. Are you sure the input is not a serial stream? You are indicating that xi into the box is 1 signal (not 16 signals).

I see the word "state" and think: you are not relying on simple combinational logic, but memory (flip-flops)?.

I see in the 3rd image, the last column, zi, is all zeros.

I honestly don't understand your approach.

If you could spend some time describing with words what you are thinking that would help.

8. Feb 16, 2015

### lewando

Your middle page discusses 0 bits found, 1 bit found, 2 bits found... What about 3 bits, 4 bits, and 5 bits found? Don't you need to "find" all 5 bits of the pattern?

9. Feb 16, 2015

### Max0007

Yes but I am checking from right to left and left to right. So I only have to check for 2 bits from right to left and 2 bits from left to right and Xi is what my current cell value is = fifth bit.

10. Feb 16, 2015

### lewando

I had a question buried in post #7. You need to be very specific about the input to your box-- is it a serial stream of bits (going in on 1 wire) or a 16-bit parallel word (going in on 16 wires)? If this cannot be clearly established, then it makes no sense to proceed.

11. Feb 16, 2015

### Max0007

so in my point of view if I have x=1 and other input to 0 then bout(1)/bout(0) would take the value of 01 = which means 1 bit detected.
aout(1)/aout(0) would also take the value of 01.
a serial stream of bits (going in on 1 wire)

12. Feb 16, 2015

### lewando

As an experiment, I will send you a serial stream xi, one bit at a time. Your job is to respond with zi. It will go quickly, I promise. Ready?

x0 = 1

13. Feb 16, 2015

### lewando

Alright, maybe not so quickly then...

It is approaching midnight in my time zone. Signing off. Willing to pick this up later. In the meantime, you might want to consider multiple alternatives to your approach. There is always more than 1 way to get something done.

14. Feb 17, 2015

### lewando

Having slept on this, I think it would be better if you get a chance to ask some questions. I extend an apology for not realizing sooner that your original post does not contain a question.

15. Feb 18, 2015

### Staff: Mentor

Perhaps Max0007 should clearly explain what is implied by the choice of thread title.