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                | Neff 
                    Systems Overview |  |  
 Computer-based digital data acquisition systems 
              (DAs) are used to measure physical variables such as pressure, temperature, 
              force, and flow. With such systems, the input measure is first converted 
              to an electrical parameter such as resistance, voltage or current 
              using a sensor which is external to the data acquisition system 
              where it is conditioned and converted to a digital word that is 
              equivalent to the analog signal. The digital word is then transmitted 
              to a computer where conversion to engineering units and analysis/display 
              functions are performed. Digital DAs used today are primarily multi-channel 
              systems. That is, up to N sensors are connected to a single DAs 
              where they time share common equipment. These measurement systems 
              are referred to as multiplexed data acquisition systems. Depending 
              on the extent of the shared equipment, multiplexed DAs are categorized 
              as amplifier-per-channel systems or low-level multiplexed systems.   |