From Brian Willoughby Sent Tue, Feb 6th 2018, 21:25
One does not feed digital noise /into/ an LFSR, the LFSR /is/ digital = noise. Let me modsplain this for you. The term, LFSR, stands for Linear-Feedback Shift Register. The content = of the LFSR itself is used as feedback and fed into the binary input. = Typically, the feedback is the eXclusive OR product of two or more bits = from close to the output. The only catch is that the LFSR cannot start = out with all zero bits, or it will always remain zero. The longer the = bit chain, the longer the pattern before it repeats. One can also use = just a single output bit at the end of the chain, or consume multiple = bits, although adjacent bits are not really unrelated, thus the = pseudo-random nomenclature. If you were to feed digital noise into an LFSR, it wouldn=E2=80=99t = really be an LFSR any more. The nice thing about the LFSR is that it can be implemented in software. = If you want it to be predictable, that is a better choice, because you = can shift only once for each new bit needed. If you want the LFSR output = to be unpredictable, then run it in hardware with its own bit clock so = that the sequence is not tied to any outside signal. As you probably = know, there have been chips like the MM5837 implementing this since the = seventies, if not earlier. Brian On Feb 6, 2018, at 12:41 PM, Kylee Kennedy <xxxxxxxxx@xxxxx.xxx> wrote: > Also was thinking you were going to mention the Turing Thing from Tom = Whitwell. I have a buddy that uses four of them in his eurorack for just = that sort of psuedo-randomness.=20 >=20 > Another thing to look at is the Buchla voice of uncertainty which is = digital noise into an LFSR. So it become more psuedo-random and more = musical. >=20 > I also like the Lorenz Affect LFO from Non-Linear Circuits called = 'Sloth' for slow evolving LFOs that do weird phase shifts. It's not = exactly what you are asking for but I use it similarly to a = psuedo-random source. >=20 >=20 > Kylee