Algorithm development and general DSP issues
Moderator: frank
aziltz
Posts: 13 Joined: Mon Feb 04, 2013 12:09 pm
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by aziltz » Mon Feb 04, 2013 12:12 pm
Hi, I'm new to the FV-1 game. Is it possible to generate a 2nd or slave LFO that has a controllable phase offset from a master LFO?
Thanks.
frank
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by frank » Mon Feb 04, 2013 12:45 pm
Each LFO puts out +/-sin and +/- cos so you have 4 phases all 90 degrees apart from each other. If you need it to be an arbitrary phase then it is not possible.
aziltz
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by aziltz » Mon Feb 04, 2013 2:03 pm
I see, thanks. Could an allpass applied to an LFO to give arbitrary control over the phase?
slacker
Posts: 116 Joined: Tue Feb 01, 2011 1:13 pm
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by slacker » Mon Feb 04, 2013 2:43 pm
Haven't fully thought this through but you should be able to do it using the ramp LFOs, you could run them both at the same speed but reset one of them at any point along the other, this will give you what ever phase difference you like.
The ramps can be rectified to give triangles and clipped or filtered to give something approaching a sine.
aziltz
Posts: 13 Joined: Mon Feb 04, 2013 12:09 pm
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by aziltz » Mon Feb 04, 2013 6:55 pm
thanks, I will look into that.
rocket512
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by rocket512 » Tue Feb 05, 2013 3:55 am
aziltz wrote: I see, thanks. Could an allpass applied to an LFO to give arbitrary control over the phase?
Good old math might be useful:
sin(x+y) = sin(x)*cos(y) + sin(y)*cos(x)
y could be the arbitrary Phase offset
frank
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by frank » Tue Feb 05, 2013 2:36 pm
Yeah, rocket512 is right, that would probably work.
aziltz
Posts: 13 Joined: Mon Feb 04, 2013 12:09 pm
Location: Williamsburg, VA
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by aziltz » Tue Feb 05, 2013 7:19 pm
I looked that up right before asking my question too! Thanks all.