Fourier transform

Grating lobes in phased arrays — when they appear and how to avoid them

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Grating lobes in electronic scanning: the spacing / scan-angle condition that creates false main beams, and design rules to keep them out of visible space.

Electronic Scanning Arrays

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Articles in this series Phased array antenna — an introduction Electronic scanning arrays (this article) Grating lobes in electronic scanning Array pattern multiplication Introduction Suppose the antenna cannot move — a radar on a mast, a panel on a tower — but you still need the beam to point somewhere else. That is electronic scanning: … Read more

Phased Array Antenna – an introduction

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Articles in this series Phased array antenna — an introduction (this article) Electronic scanning arrays Grating lobes in electronic scanning Array pattern multiplication Introduction Suppose you need a radar beam that jumps from one track to another in a few microseconds, or a base-station panel that must serve users across a sector without swinging a … Read more

Chirp signal spectrum — frequency sweep, FFT, and PSD (Matlab & Python)

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Generate a linear chirp, view the spectrogram/FFT, and estimate PSD in Matlab or Python — how the instantaneous frequency sweep fills the spectrum.

Generating Basic signals – Rectangular Pulse and Power Spectral Density using FFT

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Numerous texts are available to explain the basics of Discrete Fourier Transform and its very efficient implementation – Fast Fourier Transform (FFT).  Often we are confronted with the need to generate simple, standard signals (sine, cosine, Gaussian pulse, square wave, isolated rectangular pulse, exponential decay, chirp signal) for simulation purpose. I intend to show (in a series of articles) … Read more