Michael Lee Posted August 15, 2021 Share Posted August 15, 2021 I will use this thread to share with everyone the raw output of my different random noise / bit sources from the FPGA. A lot of these designs are already in the scientific literature. Only a few are truly my own creations, built on the ideas of previous ones. Each one has a rate of 50 Mbits per second, because this is the base clock speed of the device. The system clock can be sped up to about 200 MHz without overheating, but for now 50 MHz should be more than enough. Also, you can run many of the sources in parallel. For example, you could have 20 sources running on one 50 MHz FPGA to get a total of 1 Gbits per second. As you'll see, none of my sources are perfectly random at 50 MHz. Although, if you set the bar lower to say 1 Mbit output, many should pass randomness tests. I believe that one or more of these sources, and perhaps new variants yet undiscovered can hold an ITC signal. But that won't be the direct purpose of this thread. One of the most basic things people look for in random bit streams is called "bias." This is usually measured as the number of 1's divided by the total number of bits. 0.5 or 50% is the desired theoretical value. But I think this is too overemphasized in the literature, because if the bias = 0.5 isn't met, people will revert to "whitening" techniques to make the bit stream look more random. Now if your goal is generate cryptographic keys to store your cryptocurrency, whitening may be fine. But if you're trying to "hear" spirits, etc, whitening might end ruining the weak signal we're trying to pick up. Thus I want to introduce a new metric, I just thought up (special thanks to spirit team , bias variance. If a bias is 0.75 for a particular noise source, that should be fine, as long as it doesn't keep changing over time. We can always subtract the mean, if we're doing things like summing up the bits over an interval (remember the 6,125,000 samples per group bit?) 1 Quote Link to comment Share on other sites More sharing options...
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