Analog Electronics Unplugged: Signals and Systems Basics Quiz Quiz

Challenge your understanding of fundamental concepts in analog electronics, focusing on signals, systems, and their core properties. This engaging quiz helps learners identify key differences between signal types, system characteristics, and apply essential analysis skills relevant to signals and systems theory.

1. Continuous-Time vs Discrete-Time Signals

   Which type of signal would represent temperature variations recorded every second by a digital thermometer?

   1. Periodical signal
   2. Continuous-time signal
   3. Discrete-time signal
   4. Analog signal

   Explanation: Discrete-time signals are defined only at specific, evenly spaced time intervals, such as measurements taken each second by a digital thermometer. Continuous-time signals, on the other hand, exist for every possible instant in time and are not limited to certain moments. An analog signal can be either continuous or discrete, but does not specifically imply sampling at intervals. A periodical signal refers to repeating patterns, which may or may not apply to this context.

2. System Linearity

   If a system satisfies the property that the response to a sum of two inputs is equal to the sum of the responses to each input individually, what property does this system exhibit?

   1. Stability
   2. Linearity
   3. Causality
   4. Time invariance

   Explanation: Linearity means that the system obeys the principle of superposition, where the response to multiple inputs is simply the sum of the individual responses. Time invariance is about the system’s consistency over time, while causality ensures that outputs depend only on present and past inputs. Stability describes whether the system’s output remains bounded when the input is bounded, which is not specifically about superposition.

3. Even and Odd Signal Decomposition

   Given a signal x(t), how can it be decomposed for analysis purposes?

   1. As the sum of its even and sinusoidal components
   2. As the sum of its periodic and exponential components
   3. As the sum of its odd and exponential components
   4. As the sum of its even and odd components

   Explanation: Any signal can be uniquely expressed as the sum of its even and odd parts, facilitating simpler analysis in various systems. The other options confuse types of basic components: sinusoidal and exponential parts do not always directly apply to all signals, and periodicity is a distinct property unrelated to evenness or oddness. Therefore, only the sum of even and odd components is correct for universal decomposition.

4. Impulse Signal Characteristic

   What is the defining property of an ideal delta (impulse) signal δ(t) in continuous time?

   1. It is zero everywhere except at t = 1, with area 1
   2. It repeats periodically every unit time
   3. It is always equal to 1 for all t
   4. It is zero everywhere except at t = 0, with an area of 1

   Explanation: The delta or impulse function δ(t) is zero for all t except at t = 0, where it has an infinite value such that its total area is 1. It does not occur at t = 1 (which is a distractor) and is not constant everywhere (as in 'always equal to 1'). The impulse is not periodic, as suggested by the last choice.

5. System Causality

   If a system’s current output depends only on present and past input values, what key property does this system have?

   1. Anti-causality
   2. Causality
   3. Time variance
   4. Linearity

   Explanation: A causal system is one whose output at any time depends only on current and previous input values, never on future values. Linearity is unrelated to input timing, and time variance refers to a system’s output changing if the input is delayed. Anti-causality is the opposite of causality, where outputs would depend on future inputs, which does not apply here.