Modulation Lab

What is happening here?

Modulation shapes a high-frequency carrier \(c(t)=A_c \cos(2\pi f_c t)\) with a message \(m(t)\) so it can be transmitted or analyzed efficiently. In this lab you can explore how different analog schemes affect the resulting waveform and how noisy channels distort them.

• Amplitude Modulation (AM): \(s_{AM}(t) = A_c\bigl[1 + m(t)\bigr]\cos(2\pi f_c t)\)
• Frequency Modulation (FM): \(s_{FM}(t) = A_c \cos\bigl(2\pi f_c t + \beta \sin(2\pi f_m t)\bigr)\)
• Phase Modulation (PM): \(s_{PM}(t) = A_c \cos\bigl(2\pi f_c t + k_p m(t)\bigr)\)

Try different presets, tweak the modulation parameters and observe the spectra and demodulated signal below.