What action should be performed in accordance to the rule of signal flow theory, if the summing point is located after the take-off point in the direction of signal flow?

a. Only Summing Point should be represented by a single node

b. Only Summing Point should be represented by separate node

c. Summing & Take-off Points should be represented by a single node

d. Summing & Take-off Points should be represented by separate nodes

ANSWER: Summing & Take-off Points should be represented by separate nodes

Explanation:

According to the construction rule of signal flow graph, all summing & take-off points are absolutely represented by nodes.

Therefore, a single node is sufficient to represent the summing and take-off points,if the position of summing point is before the take-off point.

But, if the position of summing point lies after the take-off point, then both of them are represented with the assistance of separate nodes connected by a branch possessing unit value of transmittances.