Doepfer

ok, i will create such a poll, asap.


Bakis Sirros - Parallel Worlds / Interconnected / Memory Geist

[Doepfer_a100] group owner

www. parallel - worlds - music. com

www. myspace. com/ parallelworldsmusic

www. myspace. com/ interconnectedmusic

www. myspace. com/ memorygeist

www. DiN. org. uk

www. musicamaximamagnetica. com

www. shimarecords. co. uk

www. rubberrecords. gr

Athens - Greece

--- On Thu, 1/15/09, yahoo@doepfer.de <yahoo@doepfer.de> wrote:
From: yahoo@doepfer.de <yahoo@doepfer.de>
Subject: [Doepfer_a100] Tendency Processor ?
To: Doepfer_a100@yahoogroups.com
Date: Thursday, January 15, 2009, 11:56 AM










    
            > This idea sound very similar to the Blacet Improbability Drive. The

> upper and lower limits controlled by the "Width" and the center (the

> level which the random voltage fluctuate around) controlled by "level."

> The module spits out, amongst other things, random voltages btween the

> upper and lower limits as set by the width control. Check out the manual

> for better detail:

>

> http://www.blacet. com/ID.html

>

> THis functionality could be easily achieved with the forthcoming window

> comparator (I think Doepfer announced such a module) and a single random

> voltage generator. Right???

>

> Tony



If I understand everything the Tendency Mask Generator is nothing but a

random voltage source (e.g. A-118) processed by a VCA (that controls the

spread or width) and a unit that adds an offset voltage. In this patch one

has to voltage controlled parameters: width W (VCA) and center C (offset)

and the upper and lower voltages are not controlled directly but by W and C.

But the voltages W and C can be derived from the lower (L) and upper (U)

voltage very simply. The result is:



W = (U-L)/2

C = (U+L)/2



This can be realized very simply by an adder (U+L) and subtractor (U-L)

followed by a 1:2 attenuator. The same circuit is used in the A-137-1 but in

the opposite way (i.e. upper are lower voltage are derived from center and

width, in this case for the upper and lower voltages of the upper and lower

folding level). A low cost quad OpAmp is sufficent for U+L and U-L

calculations.



It would be very easy to develop a module that consists of a VCA, the

adder/subtractor and an offset generator. Such a separate module would have

the advantage that not only a random voltage but any other control voltage

(LFO, ADSR and even audio) could be processed. The module could developed

within less than one day and the price would be in the 50-60 Euro range.



The module could look like this:



Manual Control for U (upper voltage)

CV-Input with attenuator for U (upper voltage)

Manual Control for L (lower voltage)

CV-Input with attenuator for L (lower voltage)

Input

Output



Bakis: how about a poll for such a module (maybe called "Tendency Processor"

?)



Best wishes

Dieter Doepfer



If you are interested in the equations:



U = C+W

L = C-W



calculation of W:



C=U-W

C=L+W



U-W=L+W -> U-L=2W -> W = (U-L)/2



calculation of C:



W = U-C

W = C-L



U-C=C-L -> 2C=U+L -> C = (U+L)/2




      

    
    
	
	 
	
	








	


	
	


      

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