

                 README FILE FOR THE HADLOP ARCHITECTURE
                                 oaslm.arc
                               January, 1997

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  This architecturesimulates an optical image processor consisting of 3
  cascaded "Optically Adressable Spatial Light Modulators" based on fluid 
  liquid crystal (FLC) devices published by Kurokawa "Ferroelectric
  Liquid Crystal Spatial Light Modulator And Their Applications",
  Ferroelectrics, 1993.

  The functionality of such a FLC is modelled using a LOGIC element.
  Every pixel is handled as a smart pixels processing element. 
  Hence, the dimension of a defined smart pixels processing element
  within this LOGIC element is 1x1. 


                       The LOGIC primitive:

  The logic element has an internal variable 'content' which displays
  the state of the FLC pixel. If 'content' is set to 1 the pixel is 
  transparent, otherwise it is opaque.

  Input/Output Data:
  The identifyer of the optical input and output is called 'pixel'.

  External Data:
  The two external variables 'WRITE' and 'READ' are used for simulating the
  read and write cycle of such a FLC-SLM. 

  The third external variable 'POLAR' displays the voltage applied to the 
  FLC-SLM. If the variable is set - this means a positive voltage and the
  image stored in the FLC is given out in the same way as it was given in.
  If the variable is not set this corresponds to a negative voltage and the
  image will be inverted by reading out.

  Equations:
  'content' is becoming 1 if the input 'pixel' is also 1 during a WRITE cycle.
  A FLC pixel which is already set to 1 remains in this state. Hence, the 
  equation for 'content' results in

        content = WRITE & pixel + content.

  The output information ('pixel') is given out during the read cycle. A
  light beam striking the FLC pixel produces a 1 in two cases.
    One case is if 'content' is set and the POLARization of the
    voltage is 1.
    The other case corresponds to the situation that 'content' is 0 and the
    POLARization of the voltage is negative.
  Hence, the equation for 'pixel' results in 

       pixel = READ & pixel & (content & POLAR + ~content & ~POLAR). 


  The functionality of a FLC-SLM modelled as LOGIC has two inputs. One for 
  writing information and the other one for reading out stored data.
  Therefore the INPUT elements for reading contain additional empty masks
  - just masks in which all bits are set.

  Hence, a FLC-SLM in our HADLOP model consists completely of two INPUTS,
  a JOIN for combining the data coming out of the inputs and a LOGIC element.



/***************************************************************************/

  Simulation parameters: Clocks: 4

/***************************************************************************/


  During the simulation two data images A and B are combined. Data image A
  contains the letters FSU (Friedrich Schiller University), Data image
  B contains two simple geometric figures. 

  Adjusting the external variables 'POLAR' in the left (corresponds to A)
  and in the middle LOGIC element (corresponds to B) allows to read out
  the image identical or inverted.


                                  Examples:
  ---------------------------------------------------------------------------

  i)

    left LOGIC element       middle LOGIC element

    POLAR (3rd column)       POLAR (3rd column)

    cycle 2   1               step 2   0
    cycle 3   0               step 3   1


    step 4 & step 6 --> A~B
    step 5 & step 7 --> AB      

    ---> A~B + AB = A


  ii)

    cycle 2   0              cycle 2    1 
    cycle 3   1              cycle 3    1

    cycle 2 & cycle 2 --> ~AB
    cycle 3 & cycle 3 -->  AB
 
     ---> ~AB + AB = B


  iii)

    cycle 4   0              cycle 6    1 
    cycle 5   1              cycle 7    0

    cycle 4 & cycle 6 --> ~AB
    cycle 5 & cycle 7 -->  AB
 
    ---> ~AB + A~B = A exor B




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    HADLOP homepage:

    http://www2.informatik.uni-jena.de/pope/HADLOP/hadlop.html

    If you have questions send an e-mail to:

    hadlop@informatik.uni-jena.de


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