Apollo Comms Part 30: We explain and debug modern (CD4046B) and vintage (Apollo) PLL circuits.
We build a Phase Locked Loop (PLL) FM demodulator for extracting the Apollo downvoice from its subcarrier, using the classic 7046B IC. But in the meantime, as luck would have it, NASA's own S-band receiver's PLL seems to have gone bonkers, and we can't lock to the spacecraft microwave downlink anymore! So we'll get very hands on with PLLs in this episode. Expect a healthy dose of PLL elevator music.
Apollo Comms Playlist: • Apollo Comms Part 1: Opening the S-Ba...
Older video on Fractional-N PLLs, used for frequency synthesis: • HP 3325A Bonus Material: Fractional-N...
Links to doc:
https://www.curiousmarc.com/space/apo...
https://virtualagc.github.io/virtuala...
https://www.ibiblio.org/apollo/
https://www.ibiblio.org/apollo/Docume...
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Elevator Music Credit: Crinoline Dreams by Kevin MacLeod
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