Parameters: Range sampling rate = 15MHz, Range size = 1000 samples,
Pulse length = 100 samples, Pulse BW = 7.5MHz, Radar frequency = 5GHz.
The priority was in making the animation fit into normal resolution
pixels, rather than match any known system.
DAC graph represents chirp that is upconverted. The chirp linearly
changes frequency from -3.75MHz to +3.75MHz, after upconversion this
would be linear chirp from 4.99625GHz to 5.00375GHz. This is what is
actually transmitted out of the antenna. Unfortuately I cannot think of
a way to visualize this on the expanding wavefronts.
ADC graph represents a received echo of downconverted 1000 complex
samples.
This demo assumes that we only have two ideal point targets that
backscatter anything at all. Everything else is represented as order of
magnitude lower ADC background noise. In real life essentially every
point produces some backscatter. And to complicate matters even more due
to the nature of SAR, everything in azimuth direction before and after
also produces data. Thus real level 0 range rows look like "noise."
This visualization should give an overall idea, of how a SAR level 0
range row is formed.