Do you have an example of a truly random phenomenon?

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  • #101
Baluncore
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− so far, no competent math or science guy or gal to whom I've described the notion has to me decried the idea as in any way not ok.
An XOR is a product detector, so you will have built a correlation receiver that will detect cross channel interference. Where can I find Cosmic Microwave Background free from interference? Would it not be better to throw out the dishes and just terminate the antenna leads in hot resistors with Johnson noise?

What are the “SETI filters”? Presumably you take raw data and remove signals, effectively maximising entropy of the data set. The result will not have recognisable patterns, but it will contain patterns you did not consider in the filters. In effect, you are reading the tea leaves.

That ignores the fact that real random noise contains short sequences of recognisable patterns. If you remove those patterns you have coloured the data, and the result is guaranteed NOT random.

For all we know, extraterrestrials maximise channel utilisation and correct all errors by communicating efficiently in what we see as random noise.
 
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  • #102
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@Baluncore, I recognize that XOR gates can be employed (e.g.) in phase detectors, but I had in mind single gate modulo-2 binary addition of two different signal sets for purpose of co-masking to produce a 3rd signal set that I supposed would not exhibit regularities that were present in either of the two original signal sets. Do you think that this notion is in error?
 
  • #103
Baluncore
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... for purpose of co-masking to produce a 3rd signal that I supposed would not exhibit regularities that were present in either of the two original signal sets. Do you think that this notion is in error?
Yes.
Fundamentally it is a product detector that will lift any common signal out of the noise. It will also place harmonics of both signals into the resulting noise floor.

Wide-band radio astronomy receivers, that digitise the signal with a comparator to one bit, are gain independent, and use XOR gates to correlate signals in shift registers with changing lags. Spread spectrum systems use XOR gates to modulate and demodulate the signals. They also use them as correlators in the PLL to lock the spreading code clock rate.

An XOR gate is not different to a broad-band frequency mixer. Where A, B and Z are the probabilities of boolean signals being high, the XOR statistics arithmetic is as follows;
Z = A*(1-B) + (1-A)*B
That is the same as a frequency mixer.

XOR and XNOR are really the same. Note that if you have a “Random” bit stream, and pass it through an inverter, it becomes NOT “Random”. You must watch out for these word games.
 
  • #104
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XOR and XNOR are really the same.
I'm confident that you well know that XOR means one or the other is true, but not both, whereas XNOR (IFF) means either both are true, or neither is true ##-## they're similar; in that one is the inverse of the other, but they're not what I would call "really the same".

Baluncore said:
Note that if you have a “Random” bit stream, and pass it through an inverter, it becomes NOT “Random”.
How would changing all the 1s to 0s and all the 0s to 1s make a bit stream less random?

You must watch out for these word games.
Yes.
 
  • #105
sophiecentaur
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How would changing all the 1s to 0s and all the 0s to 1s make a bit stream less random?
+1. Modulation (which is what's happening, basically) can't alter randomness.
 
  • #106
Baluncore
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I'm confident that you well know that XOR means one or the other is true, but not both, whereas XNOR (IFF) means either both are true, or neither is true − they're similar; in that one is the inverse of the other, but they're not what I would call "really the same".
NOT(XOR) = NXOR = XNOR; which is just another word game.
Randomness is independent of signal polarity.
The power spectrum is independent of signal polarity.
Minimising entropy is independent of signal polarity.
The vast majority of signals are independent of polarity.
Does a telephone conversation sound different if the twisted pair has the mate and colour swapped ?
 
  • #107
gmax137
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Does a telephone conversation sound different if the twisted pair has the mate and colour swapped ?
Rhetorical question?
 
  • #108
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To quote an answer from a more knowledgeable person than myself on the topic, given to me from a question I posed as, "Can you generate a random number from a machine?"

Not sure that's all relevant, or that I can support the assertion, but that is the mostly complete answer. He seemed to be aware of something similar vis a vis white noise generators for randomness.

I want to also reiterate that I believe radioactive decay is considered stochastic (random?) at the individual atomic level. From the wikipedia on radioactive decay, we can see there are some applied methods that work from the premise that radioactive decay is random:


from: https://en.wikipedia.org/wiki/Radioactive_decay
I seem to remember some programs using noise from GPUs (how the audio [EDIT: Yeh ok, bad word] was captured I can't seem to remember...) to seed random number generators. Theoretically at least, one could use the noise from a *NIX HDD shredding data and base your numbers on that.

I admittedly didn't read your entire thread though. If I know you guys just superficially you probably already descended into some black hole entropy theory or something, where, as normally you couldn't get out, I wouldn't be able to get in in the first place. :)

Regards.

Stumbled across this, admittedly a little dated, reference:

Quantum Random Number Generators

Although I think skimmed enough to understand that quantum randomness wasn't really the subject.
 
  • #109
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