# Is a sine signal a continous signal (analog signal) or a digital signal (discrete signal)?

Also can we have an analog signal in alternating current?

## Answers and Replies

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phinds
Science Advisor
Gold Member
2019 Award
A sine wave is an analog signal. Alternating current is nothing BUT analog, so I don't even understand how you can ask the question. I think you must have been given some VERY misleading information about what is digital and what is analog.

Thank you for your answer, I was a bit confused that's why I asked this question.

I wasn't sure if my thinking was correct but now I see that I was correct.

At a test I gave the example of an analog signal as a sine wave.

boneh3ad
Science Advisor
Gold Member
You can have a digital representation of a sine wave as well. I wouldn't have given you credit on an exam answered in that fashion if I was grading. You can have a signal, either analog or digital, that is sinusoidal, but a sine is not descriptive enough to distinguish between an analog and a digital signal.

I was asked to draw a continuous signal and I draw a sine wave, which it is continuous.
Can someone provide me other(better) examples?

Thanks in advance.

phinds
Science Advisor
Gold Member
2019 Award
I was asked to draw a continuous signal and I draw a sine wave, which it is continuous.
Can someone provide me other(better) examples?

Thanks in advance.
You did just fine. There is no need for any "better" example.

berkeman
Mentor
A "digital" version of a sine wave would be something like the output from a Digital to Analog Converter (DAC). Do you know what a sine wave output from a DAC would look like, and how it would be different from the analog sine wave that you drew on the test?