What is a finite state transducer?

Question

Can someone please tell me what a finite state transducer is?

I have read the Wikipedia article and don\'t understand a thing.

Answer 1

In as simple terms as possible, I understand that an FST is essentially a "thing" that moves from one state to the next based on an input tape and writes to a different output tape. A tape is essentially a set of inputs like characters in a string.

The entire FST is represented by a set of states and links between them. A link is "activated" when its input condition is correct and then gives then next state the adjusted tape.

For example let's say an FST starts with the tape abc at state 1. A link to state 2 matches a and changes that to b. This would get activated, set the output tape to just b, and pass the remaining bc to state 2. As you can see, each state is only activated if there is a link to it whose input condition was correct, passes the remaining input to the next state, and writes to a separate output tape. Each FST runs across the tape once and output to another tape once.

To get a more clear understanding of them read and take a look at the diagrams in this article (original broken link).