Block diagram reduction is a technique to simplify complex systems represented by block diagrams into simpler systems. A block diagram uses blocks and lines to represent the relationships between systems and subsystems. Block diagram reduction uses standard rules to convert the transfer functions of multiple subsystems into a single transfer function representing the entire system. The key points are that the product of transfer functions in the forward direction and around any feedback loops must remain the same after applying the reduction rules.

1. Block Diagram Reduction
- Ameya P. Nijasure
napradeep@mes.ac.in

2. Block Diagrams
● Representation of system function by blocks connected by lines.
● Represents relationship between systems & subsystems.
● Applications include engineering in hardware design, electronic design, software design,
and process flow diagrams.
Consider an example
● There is an input & output.
● Direction of function can
be either forward(i/p to
o/p) or feedback(o/p to
i/p).
● G & H are representation
of Transfer functions(t.f.)
of each sub system.
● Lines represents
relationships between
subsystems.

3. Block diagram components

4. Block diagram Reduction
R(s) Y(s)Converting these complex systems into
Simple systems
● One t.f representing components of
all subsystems.
● Using standard rules
Points to remember
● The product of the transfer function in the feed forward direction must remain same.
● The product of transfer functions around the loop must remain same.

5. BLOCK DIAGRAM REDUCTION RULES
NOTE : BLOCKS IN PARALLEL MUST HAVE
SAME DIRECTION.

6. BLOCK DIAGRAM REDUCTION RULES

7. BLOCK DIAGRAM REDUCTION RULES

8. BLOCK DIAGRAM REDUCTION RULES
NOTE :
● TO ELIMINATE FEEDBACK LOOP WE NEED ONE FORWARD PATH TF , ONE FEEDBACK TF, ONE
SUMMING POINT & ONE TAKEOFF POINT.
● G1 & H1 CAN BE UNITY FUNCTIONS..

9. Thank you….!!
- Ameya P. Nijasure
napradeep@mes.ac.in