Transmitting a radio frequency signal in pulses markedly changes in the signal's spectrum, as observed by the tuned circuit of a receiver. Whereas the spectrum of a continuous wave of constant wavelength consists of a single line, the spectrum of a single pulse of the same wavelength covers a band of frequencies and has a sin x/x shape. The width of the central lobe of this spectrum varies inversely with pulse width. If the pulses are as narrow as those used in many radars, the central lobe may be several megahertz wide.

Chapter Contents:

• Illustrative Experiments
• Bandwidth
• Coherence
• Line Width versus Duration of Pulse Train
• Spectral Sidelobes

Inspec keywords: radar receivers; radar signal processing; Doppler radar

Other keywords: radio frequency signal transmission; receiver; Doppler radar; tuned circuit; pulsed signal spectrum

Subjects: Signal processing and detection; Radar equipment, systems and applications