The radar ambiguity function is defined as the absolute value of the envelope of the output of a matched filter when the input to the filter is a Doppler-shifted version of the original signal, to which the filter was matched. Ambiguity functions are usually analyzed on a single pulse basis. Hence, in a work of this nature on continuous wave (CW) radars, there is no error as the results apply equally well to CW radar waveforms. However, in CW radars there is in advantage not shared by modulated pulsed radars, viz. the concept of periodic ambiguity function (PAF). The concept of PAF introduces the fact that in certain class of phase-coded signals employed in CW radars, one can obtain an autocorrelation function devoid of side lobes on the delay axis.

Chapter Contents:

• 3.1 Introduction
• 3.2 Examples of Ambiguity Functions
• 3.2.1 Single-Frequency Pulse
• 3.2.2 Linear FM Pulse
• 3.2.3 Stepped-Frequency Waveform
• 3.2.4 Digital-Coded Waveforms

Inspec keywords: pulse modulation; phase coding; CW radar; Doppler shift; matched filters; radar signal processing; Doppler radar; correlation theory

Other keywords: continuous wave radar; Doppler shift; matched filter; PAF; CW radar; autocorrelation function; phase coded signal; radar signal processing; delay axis; modulated pulsed radar; periodic ambiguity function; radar ambiguity function

Subjects: Modulation and coding methods; Radar equipment, systems and applications; Filtering methods in signal processing