Both have totally different roles the Business Analyst "BA" is capable of defining the business requirements, & able to determine & examine the Operation processes "Including the IT Processes", make enhancement according to the rules of BPM concepts resulting in a new enhanced business processes, it worth to mention that BA has international certificate CBAP authorized by the international institute of business analysis IIBA.
The rule of System Analyst "SA" is part of the Software development lifecycle he works after the BA finish the requirements package starting to design the model build the use case ... making prototypes (while BA can do same thing)
