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TonyDuell · 25th Apr 2019, 6:12 pm

OK, consider Q13. It's 'on' (high, logic 1, whatever you want to call it) for half the time. And off of the other half of the time.

Now consider Q12. It is also 'on' half the time, but it changes twice as fast as Q13. In fact Q13 will change when Q12 changes from 'on' to 'off'.

So Q12 and Q13 are 'on' together only a quarter of the time. Now if you combine those 2 signals with an AND gate the output of the AND gate is 'on' when both inputs are 'on'. That's a quarter of the time, and overall the signal repeats at the same speed as Q13.

Now bring Q11 into the circuit too. It changes twice as fast as Q12 (so 4 times as fast as Q13). Q11, Q12 and Q13 are 'on' together only 1/8 of the time. AND all 3 signals together and you get a signal that repeats at the same speed as Q13, but which is 'on' for 1/8th the time, off for the other 7/8ths of the time.

To AND the 3 signals you need an AND gate with 3 inputs. I simply told you to wire 2 2-input AND gates together to make such a gate.

25th Apr 2019, 6:12 pm	#82
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Turntable Stroboscope OK, consider Q13. It's 'on' (high, logic 1, whatever you want to call it) for half the time. And off of the other half of the time. Now consider Q12. It is also 'on' half the time, but it changes twice as fast as Q13. In fact Q13 will change when Q12 changes from 'on' to 'off'. So Q12 and Q13 are 'on' together only a quarter of the time. Now if you combine those 2 signals with an AND gate the output of the AND gate is 'on' when both inputs are 'on'. That's a quarter of the time, and overall the signal repeats at the same speed as Q13. Now bring Q11 into the circuit too. It changes twice as fast as Q12 (so 4 times as fast as Q13). Q11, Q12 and Q13 are 'on' together only 1/8 of the time. AND all 3 signals together and you get a signal that repeats at the same speed as Q13, but which is 'on' for 1/8th the time, off for the other 7/8ths of the time. To AND the 3 signals you need an AND gate with 3 inputs. I simply told you to wire 2 2-input AND gates together to make such a gate.