What do triangles mean in frequency aliasing depiction?

As a short first answer: The triangles indicate the extent of the frequency content of the signal (→ bandwidth).

1. What is aliasing theorem?
2. What is aliasing frequency?
3. What is aliasing effect formula?
4. What does sampling theorem state?

What is aliasing theorem?

Aliasing is when a continuous-time sinusoid appears as a discrete-time sinusoid with multiple frequencies. The sampling theorem establishes conditions that prevent aliasing so that a continuous-time signal can be uniquely reconstructed from its samples. The sampling theorem is very important in signal processing.

What is aliasing frequency?

Aliasing occurs when an oscilloscope does not sample the signal fast enough to construct an accurate waveform record. The signal frequency is misidentified, and the waveforms displayed on an oscilloscope become indistinguishable. Aliasing is basically a form of undersampling.

What is aliasing effect formula?

Aliasing is the name we give to the phenomenon when two distinct continuous signals x 1 ( t ) and x 2 ( t ) produce the same sequence of sample values when sampled at a fixed rate . More specifically, we usually think of aliasing in terms of pure (sinusoidal) tones x ( t ) = A ⋅ cos ⁡ ( 2 π ⋅ f ⋅ t + ϕ ) .

What does sampling theorem state?

The Sampling Theorem states that a signal can be exactly reproduced if it is sampled at a frequency F, where F is greater than twice the maximum frequency in the signal.