Which statement best describes digital signals?

Which statement best describes digital signals?

• A. They can take any real number value
• B. They are either high or low (binary)
• C. They vary continuously with time
• D. They are always in a sine wave shape

Answer: (B)

Digital signals encode information using discrete, distinct voltage levels. The most common form uses two levels—high and low—representing binary 1 and 0. Because the amplitude is limited to these fixed levels, the signal stays constant between transitions and only changes when a new symbol is sent. This discreteness makes digital signals robust to noise and easy to process with digital logic and repeaters. The other statements describe analog behavior. Allowing any real-number value would mean a continuous range of amplitudes, which is not how digital signals operate. Varying continuously with time suggests a smooth, gradual change in amplitude, whereas digital signals switch between fixed levels rather than sweeping through values. A sine-wave shape is not a defining feature of digital signaling; digital waveforms are often square-like pulses or abrupt steps rather than pure sine waves.

Digital signals encode information using discrete, distinct voltage levels. The most common form uses two levels—high and low—representing binary 1 and 0. Because the amplitude is limited to these fixed levels, the signal stays constant between transitions and only changes when a new symbol is sent. This discreteness makes digital signals robust to noise and easy to process with digital logic and repeaters.

The other statements describe analog behavior. Allowing any real-number value would mean a continuous range of amplitudes, which is not how digital signals operate. Varying continuously with time suggests a smooth, gradual change in amplitude, whereas digital signals switch between fixed levels rather than sweeping through values. A sine-wave shape is not a defining feature of digital signaling; digital waveforms are often square-like pulses or abrupt steps rather than pure sine waves.