Doepfer

Am 18.11.2014 17:30, schrieb David Kellett davidkellettwoulf@yahoo.com 
[Doepfer_a100]:
>
>
> But I'm still not quite clear how I would create
> a CV based on the rate of change of another CV
>
Thats where I jumped in: Getting a CV based the change amount of an 
incoming CV is very tricky (see below).

While getting a CV based on the rate of incoming triggers (which is 
proportional to the amount of change of the CV) is quite easy and reliable.


If you don't want to go the way via the triggers, then split the 
incoming CV in a multiple. One path goes into a slew limiter and then 
into a polarizing mixer; the other path goes straight into another 
channel of the polarizing mixer. Mix the original full positive, the 
slewed signal fully inverted. The output of the polarizing mixer will 
now send a voltage, that is the higher, the faster the input CV is 
rising. Unfortunaly it will be a negative voltage, if the input CV is 
falling. That is the point where it gets difficult. You have to send 
both signals also into a comparator, which will tell you whether the 
voltage is rising or falling with an logical signal. With that signal 
you can use a switch to add or bypass a inverter after the output of the 
polarizing mixer. Thats it.... :-/

And btw: this will not show a true value of the changge amount because 
the slew does not change linear. It would be better to have a CV-delay 
instead of a slew limiter.