Are Perfomance Management System And Performance Appraisal System Different?

Hello all,
I'm in my 4th sem MBA and doing my project at a company. I have chosen "Performance Management System" as my topic. From the little theory i had known thought its different from "Performance Appraisal", but now finding it a little difficult to draw a line between the both. So please help me understand the same. .please.

Performance appraisal is but only one part of the bigger process of performance management. So, the short answer is that performance appraisal (annual review, employee review) fits under performance management. performance appraisal, on its own, doesn't result in great gains in performance or productivity
Performance management is an ongoing communication process, undertaken in partnership, between an employee and his or her immediate supervisor that involves establishing clear expectations and understanding about:
the essential job functions the employee is expected to do
how the employee's job contributes to the goals of the organization
what "doing the job well" means in concrete terms
how employee and supervisor will work together to sustain, improve, or build on existing employee performance.

Thats really informative. .So, that means PMS has more scope than Performance Appraisal. Thanx. .