Re: How to develop a random number generation device



On Thu, 06 Sep 2007 20:24:00 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 06 Sep 2007 19:46:42 -0700, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 06 Sep 2007 18:23:18 -0500, John Fields
<jfields@xxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 06 Sep 2007 15:10:40 -0700, bill.sloman@xxxxxxxx wrote:

On Sep 6, 10:49 pm, thiagu1...@xxxxxxxxx wrote:
Hi,

I'm a researcher. As a part of my project work I want to desing a
random number generated and displayed on a LCD/ LED module. Can
anybody help me out in this.

Thiagu

Search on pseudo-random binary sequence generators. Wikipedia has a
good general entry on the subject.

One way of getting a pseudo-random binary sequence is with a linear
feedback shift register - if you exclusive-OR the output with a couple
of carefully selected taps along the shift register you can guarantee
that the content of the shift register goes through all but one of tis
possible combinations.

It's often more than just a couple of the taps and, with a little
ingenuity, the "lockup" state can be included in the sequence.

If the feedback is pure xor, and it's a maximal length sequence, then
exactly one state is the lockup, and that's either all 1's or all 0's
in the register.

John

Hmmm, seems like all 0's must be the lockup for an all XOR feedback.

Sorry.
---
OK, but you missed my point, which was that it's possible to
eliminate the lockup state by forcing it to be part of the sequence.


--
JF
.



Relevant Pages

  • Re: How to develop a random number generation device
    ... Search on pseudo-random binary sequence generators. ... feedback shift register - if you exclusive-OR the output with a couple ... the "lockup" state can be included in the sequence. ... If the feedback is pure xor, and it's a maximal length sequence, then ...
    (sci.electronics.design)
  • Re: How to develop a random number generation device
    ... Search on pseudo-random binary sequence generators. ... feedback shift register - if you exclusive-OR the output with a couple ... of carefully selected taps along the shift register you can guarantee ... the "lockup" state can be included in the sequence. ...
    (sci.electronics.design)
  • Re: How to develop a random number generation device
    ... Search on pseudo-random binary sequence generators. ... feedback shift register - if you exclusive-OR the output with a couple ... the "lockup" state can be included in the sequence. ... If the feedback is pure xor, and it's a maximal length sequence, then ...
    (sci.electronics.design)
  • Re: How to develop a random number generation device
    ... Search on pseudo-random binary sequence generators. ... feedback shift register - if you exclusive-OR the output with a couple ... the "lockup" state can be included in the sequence. ... state to be zero. ...
    (sci.electronics.design)
  • Re: How to develop a random number generation device
    ... Search on pseudo-random binary sequence generators. ... couple of carefully selected taps along the shift register you can ...
    (sci.electronics.design)

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