Amplitude modulation
x(t) = c(t) · [1 + m·g(t)]Frequency modulation
f(t) = fᶜ + Δf·g(t)Sweep / chirp
Linear sweeps spend equal time per hertz; logarithmic sweeps spend equal time per frequency ratio.
Multi-tone
x(t) = Σ Aₖ sin(2πfₖt + φₖ)Burst sequence
Edge ramps reduce clicks while on/off times define the pulse pattern.