Round-Robin Scheduling Algorithm, that is used to prevent starvation. Lets say you have 4 jobs.
Job A Job B Job C and Job D
Round Robin will give each job the same amount of CPU time until they are finished.
so it will go like A B C D A B C D A B C D. for like 3 cycles each. If one of the jobs finishes it will be removed from the queue. If a job is added it will be added to the circular queue. Hope this is what you are asking for.
Your statement is correct, but I didn't agree with you on the example you presented (ABCD) when you mentioned that it Will run as ABCDABCD... The sequence ABCD gradually shrinks, if one process terminates..eg: B uses the least time units, the sequence could be ABCDACDACD...