[TXnMA]

I'm bandwidth-starved" by my lousy satellite ISP. But, I guess I better watch the video -- in hopes they will show the received signal's waveform envelope.

L-I-M, as I understand your RADAR description, the carrier was sinusoidal -- linearly frequency-swept (modulated) over a 1MHz range by a 1KHz "sawtooth" signal. Every millisecond, the modulation frequency would reach peak, then instantly drop back 1 MHz, and begin its sweep again... (IOW, I'd guess that early RADARs were modulated by a VCO -- driven by a relaxation oscillator-generated sawtooth...)

OTOH, a point source on a rapidly-spinning sphere -- Doppler-modulated by the angular velocity -- would sinusoidally reach a peak frequency, and sinusoidally drop back to minimum. Then, with the signal occluded by the object, the signal would be attenuated (below detectable level) for half a revolution, and then the half-sinewave signal would reappear. (Basically a frequency-modulated signal, driven by a half-rectified sine wave...)

Going to go "bomb" my bandwidth allocation, watch the video, hope for a look at the actual signal, and -- I hope -- stop speculating... '-)

Back soon...

[Lonesome in Massachussets]

Your understanding of LFM is spot on. Originally LFM used a dispersive delay line, with delay proportional to frequency to modulate the signal. Virtually all modern radar systems use digital waveform generators, and multiplier chains.

https://en.wikipedia.org/wiki/Chirp

[TXnMA]

Now, we have something to talk about! Thankfully, they displayed the waveform early in the video -- so I screen-grabbed it, did a little color annotation, and "parked" it up on my webdomain for us to all see:

It "is" "fast" or "brief" -- just a "spike" pulse >400 ms in duration -- (amplitude modulated, if you will...) And descending in frequency some 0.3 GHz during that time...

I would call it both amplitude and frequency modulated...

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Well, there you have it, folks -- have at it! '-)