Lesson 16 — EP for Communications#
The same spread-spectrum instinct that protects a radar protects a data link. We smear a narrowband signal into noise with DSSS and FHSS, quantify the processing gain that lets a link survive a louder jammer, and ride a signal below the noise floor.
EP for Communications
Why narrowband is easy to jam, DSSS vs FHSS, processing gain = 10·log₁₀ N_chips, J/S relief, and LPD.
FlashcardsReview deck
Key terms and relations from the lesson, in a self-test deck.
Pre-flightPre-flight quiz
Five questions to work before class — anyone can be called to the board.
SlidesLesson slides
The deck we work through in class — an HTML deck you can annotate in the browser, with a print view for saving a PDF.
DemoSpread-Spectrum Playground
Two spectrum panels, before and after despread: set the jammer's J/S, pick DSSS chips or FHSS hops, and read the link verdict as G_p clears the deficit.
DemoDSSS Correlator
Slide the right code and a wrong code along the received stream and watch the data bits reappear as correlation peaks — only for the right code, at the right time.