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#39 Random Generator

closed-accepted
nobody
None
5
2010-03-16
2010-02-13
No

The Random Generator component always generates the same sequence when the bit
sequence is small. With Data Bits equal to 1, the sequence is always 0, 1, 0, 1, 0, 1, ...
With Data Bits equal to 2, the sequence is always, 3, 2, 1, 0, 3, 2, 1, 0, ...

I noticed this when testing a sequence detector and I was trying to use the Random
Generator as a random bit sequence generator. I worked around the problem by using
the Random Generator with Data Bits equal to 8 and then using a Splitter to pull out a
single bit. I noticed, even with Data Bits equal to 8, that the lower order bits are not
random. The least sig bit always appears to go through a 0, 1, 0, 1, 0, 1 sequence.

Discussion

  • Carl Burch

    Carl Burch - 2010-03-13
    • status: open --> open-accepted
     
  • Carl Burch

    Carl Burch - 2010-03-13

    Thanks for the note. I chose a random number generator that works reasonably well (namely, the same technique that java.util.Random uses), but I omitted the crucial step of ignoring the low-order bits. What you're doing is a reasonable workaround, but I'll get the fix into the next version.

     
  • Carl Burch

    Carl Burch - 2010-03-16

    Repaired in version 2.3.3, which was just released. Thanks for the report.

     
  • Carl Burch

    Carl Burch - 2010-03-16
    • status: open-accepted --> closed-accepted
     

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