$ Documentation in 'process.mac'


      Functions to build the NAPA cell corresponding to Z transfer functions (CYCLE = 1, PHASE = 2) 
  
      Z1_CELL(sig)   builds the XFER followed by ZTRANS NAPA cell   (CYCLE modeling) 
      Z2_CELL(sig)   builds the XFER followed by ZTRANS NAPA cell   (PHASE modeling)