Jim Thompson
Wrote in message:
On Wed, 01 Apr 2015 11:53:10 -0700, Jim Thompson
wrote:

On Wed, 01 Apr 2015 13:27:06 -0500, John Fields
wrote:

On Wed, 01 Apr 2015 11:00:25 -0700, Jim Thompson
wrote:

For a simulation situation I need a random number generator with a
twist...

What I need to simulate is a "random" selection of one-of-16 outputs.

Clock "speed" is 12.5kHz ;-)

Built of 74HCxx parts is preferred... I have a full ensemble of those
device in my PSpice library.

Thanks in advance.

...Jim Thompson

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If you use something like an HC154 with an LFSR driving its address
inputs to generate random one-hots on its outputs, will that work
for you?

John,

What are you saying... take the outputs of the LFSR broadside to drive
the address lines of the 'HC154?

I think that would do it.

Thanks also to Lasse for the same suggestion.

...Jim Thompson

I was puzzling over how to get 0000, but then it dawned... just use an
8-bit LFSR and use the last 4-bits.

It would be less than random because 0000 is still less likely.
Better to use a fast counter and latch it before the
154.

Because it's not physical maybe you'd have to jiggle the fast
clock with a large resistor to one of the bits, if Spice would
have a tendency to make one clock an exact multiple of the other.


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