Mock Exam on Block Diagrams

In a block diagram of a linear, time-invariant system, which of the following are considered fundamental elements?

• Signals, systems, summing junctions, and pickoff points

• Inputs, outputs, controllers, and plants

• Transducers, actuators, sensors, and disturbances

• Mathematical models, differential equations, and transfer functions

The characteristic of a summing junction in a block diagram is that the output signal is the:

• Product of the input signals

• Algebraic sum of the input signals

• Difference between the input and output

• Ratio of the input signals

A pickoff point in a block diagram serves to:

• Combine multiple signals into one

• Distribute a single input signal to several output points undiminished

• Amplify or attenuate a signal

• Convert an analog signal to a digital signal

Which of the following is NOT one of the three basic forms for interconnecting subsystems in a block diagram?

• Cascade

• Parallel

• Inverse

• Feedback

When subsystems are connected in cascade, their equivalent transfer function is found by:

• Adding their individual transfer functions

• Subtracting their individual transfer functions

• Multiplying their individual transfer functions

• Dividing their individual transfer functions

For subsystems connected in parallel, their equivalent transfer function is found by:

• Adding their individual transfer functions

• Multiplying their individual transfer functions

• Dividing their individual transfer functions

• Taking the inverse of their individual transfer functions

The feedback form in a block diagram is fundamental to the study of control systems engineering because it:

• Simplifies the mathematical modeling of individual subsystems

• Allows for algebraic manipulation of differential equations

• Forms the basis for analysis and design of closed-loop systems

• Is the only form that allows for computer-aided design

When moving a block from the right to the left past a summing junction, the block must:

• Be inverted and placed in the feedback path

• Be duplicated and placed in parallel paths

• Be applied to all inputs of the summing junction

• Not be moved, as it changes system dynamics

What is the primary purpose of block diagram reduction?

• To simplify the representation of individual subsystems

• To convert the system into a state-space representation

• To obtain a single transfer function relating the system’s input to its output

• To identify nonlinearities within the system

In block diagram reduction, what happens when a block G(s) is moved from the right to the left past a pickoff point?

• The block G(s) is also added to the branch going through the pickoff point.

• The pickoff point splits into multiple new summing junctions.

• A new block with transfer function 1/G(s) is inserted into the main path.

• The block G(s) affects the signal only on the main path, not the pickoff branch.