Signal — Radar

Advantage: Lower range sidelobes than LFM (Barker codes give peak sidelobe 1/N). Disadvantage: More sensitive to Doppler shifts. A train of narrowband pulses at different carrier frequencies synthesizes wide total bandwidth. Enables high range resolution with lower instantaneous bandwidth hardware. 5. The Ambiguity Function The ambiguity function (\chi(\tau, f_d)) is the 2D autocorrelation of the radar signal, showing the response to a target at range delay (\tau) and Doppler shift (f_d):

The transmitted signal is (s(t) = \textrect(t/\tau) \cos(2\pi f_0 t + \pi \fracB\tau t^2)). radar signal

[ s(t) = A \cdot \textrect\left(\fract\tau\right) \cos(2\pi f_0 t) ] Advantage: Lower range sidelobes than LFM (Barker codes

Resulting compressed pulse width: (\tau_comp = 1/B). Range resolution improves to (\Delta R = \fracc2B), independent of the original pulse width. 4.1 Linear Frequency Modulated (LFM) Chirp The instantaneous frequency changes linearly over time: (f(t) = f_0 + \fracB\taut). radar signal