Mini-Maxi Voltage Processor

The purpose of this module is to process multiple sources in order to retain two signals which are respectively the minimum and the maximum of the input signals. Basically, each submodule has two inputs that can be fed with either CVs or audio signals, and two outputs, one is the maximum value and the second is the minimum value. The two submodules can be chained to achieved more complex functions or combine more than two inputs. 
The design of such a min-max processor can be addressed by two different approaches : current processing (see reference at the end of the page) or voltage processing. As far as I am concerned, I preferred using the voltage one. This way the min-max processor can be built with elementary blocks such as adders, subtractors and full-wave rectifiers which only involve ordinary components (OPAs, resistors and diodes).
This circuit is mainly dedicated to processing control voltages, as an example it can be used to creat a new sequences out of the outputs of two sequencers. The outputs of the MIN-MAX modules are for one the highest pitches of both original sequences and for the second the lowest pitches... In the second case, it extracts the bass line out of the original sequences.
Also it can be used as a nice wave modifier if you feed input one with a sinewave or the triangle signal of a VCO and connect input two to a LFO, a ADSR or another VCO...

The max function or MAX(a,b) can be simulated with addition, subtraction and absolute value operators, it reads :