Which of the following is NOT classified as a digital signal?

• A. 0 and 1
• B. Analog waveforms
• C. Pulses representing values
• D. Binary representation

Answer: (B)

In the context of digital signals, the key characteristic is that they represent information in discrete values, typically as binary digits (0 and 1).

The first option, representing values through the digits 0 and 1, is a fundamental element of digital signaling. These binary representations are the building blocks of digital data.

The concept of pulses representing values also aligns with digital signaling. These pulses can signify the presence or absence of a signal, translating into binary data.

Binary representation succinctly captures how information is encoded in digital form, reinforcing the principle of discrete value representation.

Analog waveforms, however, are categorized differently. They represent continuous signals that can take any value within a given range, unlike digital signals that are restricted to specific states. This distinction fundamentally separates analog from digital, making analog waveforms the correct answer for something that is NOT classified as a digital signal.