I would try to clock the FV1 with a simple op amp VCO instead of the knowledge base circuits, as I would like to modulate its frequency via CV.
I have a couple of questions:
-How precise should be the 50% duty cycle of a square wave generator used to clock the FV1?
-Which must be the peak to peak level of the square wave?
thanks in advance for your help!
external VCO clock
Moderator: frank
Re: external VCO clock
We never tested that parameter but it should be as close to 50% as possible. I expect the PLL to be a bit forgiving.sandromatik wrote: -How precise should be the 50% duty cycle of a square wave generator used to clock the FV1?
Normal 3.3V logic levels so I would target 0.8V to 2.5V minimum and 0 to 3.3V max.sandromatik wrote: -Which must be the peak to peak level of the square wave?
Frank Thomson
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The primary problem would be the PLL unable to lock to the clock signal, this would cause multiple audible issues in the chip. I expect the PLL will be forgiving to a clock that is not 50%, just not sure how much, but I suggest you make up the circuit and just test it. We did design the FV-1 to work across a wide range of issues and the PLL was designed to lock to a wide range of signals but we never actually worked out min/max duty cycle.
Frank Thomson
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I'm interested to hear how this sounds, perhaps the LTC1799 would be a good candidate for teh clock signal. what audible effect would this have?
I place ltc1799s into the alesis hr16 drum machine replacing the clock line to the asic, by modulating the clock signal I get an 'overall' pitch control for the machine.
I place ltc1799s into the alesis hr16 drum machine replacing the clock line to the asic, by modulating the clock signal I get an 'overall' pitch control for the machine.
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