LFSR

ian-s · Posted: Fri Apr 09, 2004 5:29 am Post subject: LFSR

Hi all

This is not a complete noodle, just an illustration of an automated, pseudorandom control element, shown in yellow. It is a Linear Feedback Shift Register (LFSR) of the Fibonacci variety. The XOR gates act as binary adders in a four tap feedback loop. The position of the taps is arbitrary but for maximum non-repeating length, use an even number of prime numbered taps. The four input mixer is being used as a D2A, its cheaper DSP wise, than the actual D2A module and allows tweaking the binary weights (in this case, intervals between notes). Outputs of the network are also used for some rhythmic elements and if desired, could be fed back into the clock frequency or used in switches to dynamically change tap points etc etc.
I am not an ex NM Classic user so please forgive me if I am going over old ground.
BTW, I like the term 'noodle', although finding out the dictionary meaning was 'a musical improvisation' was a little disappointing (sort of spoilt the image). Back in the 70's, I used to call them 'autopatches', not very imaginative.

lfsr.pch2

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less random noodle control element example.

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lfsr.pch2

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mosc · Posted: Fri Apr 09, 2004 8:00 am Post subject:

Well, I like this. I can almost understand it. I used to play around, in the seventies, with Lunetta synthesizers. These were simple TTL circuits brought out to a front panel with banana jacks. These were binary up/down counters, shift registers (8bit), and modulo N dividers mostly. There were a few square wave oscillators. Lot's of fun. This is in the same vein, it seems.

Thanks for posting this.