Signals and systems: The size or magnitude of a voltage or current waveform is called its ______.

Introduction / Context:
Electrical and communication signals can be characterized by several parameters, including amplitude, frequency, and phase. Recognizing these terms is essential for understanding modulation schemes, filter behavior, and measurement readings in labs and field diagnostics.

Given Data / Assumptions:

• Waveform may be voltage or current versus time.
• We are asked about its size or magnitude.
• Basic terminology is being tested.

Concept / Approach:
Amplitude is the magnitude or “height” of a waveform, typically measured from a reference (often zero or a mean value) to a peak value. In sinusoidal signals, you may see peak, peak-to-peak, or RMS amplitude specified, each with precise definitions. The other options either relate to network access protocols (Aloha), types of modulation (angle modulation changes phase/frequency, not magnitude directly), or a transmission effect (attenuation) that reduces amplitude but is not the name for magnitude itself.

Step-by-Step Solution:

Verification / Alternative check:
Oscilloscope measurements display voltage amplitude (e.g., Vpp, Vrms) directly, underscoring amplitude as the measure of magnitude.

Why Other Options Are Wrong:

Common Pitfalls:
Mixing up RMS versus peak definitions; assuming “attenuation” names the magnitude rather than the loss process.

Final Answer:
Amplitude.