Page 261 - Fundamentals of Radar Signal Processing

FIGURE 4.19 Zero-delay cut of the pulse burst ambiguity function with M = 5
and T = 4τ.

Figure 4.20 is a contour plot of a portion of the complete ambiguity
function for this waveform. Note the broadening of the response peaks in
Doppler when sampling at the range-ambiguous delays such as 4τ and 8τ
(corresponding to ± 0.2 and ± 0.4 on the normalized delay scale of the contour

plot). This phenomenon is caused by the (M – |m|) term in the asinc term of Eq.
(4.78) and reflects the fact that at these range-ambiguous delays fewer than M
pulses are contributing to the matched filter local output peak. The reduced
observation time results in degraded Doppler resolution. Again, if the
transmitted waveform were extended by P pulses, there would be P consecutive
range peaks which retained the full Doppler resolution. This plot also illustrates

the breakup of the well-defined peaks in delay when the Doppler mismatch
reaches 1 / τ hertz (corresponding to 20 on the normalized Doppler scale of the
plot).