AM, FM, PM, ASK, FSK, PSK, QPSK, QAM, OFDM, spread spectrum, error correction, and multiplexing — why a real system picks one scheme over another, not just what each one is called.
Every modulation scheme in this module is answering the same underlying question: how many bits can a system push through a given amount of spectrum and transmit power, at an error rate the application can tolerate. This module works through that tradeoff scheme by scheme — why AM survives in aviation for a safety property FM can't offer, why BPSK still carries GPS at the edge of detectability, why QAM order shifts under your feet on a moving Wi-Fi client, and why OFDM became the default physical layer for nearly every high-throughput wireless standard built since.
By the end of this module you should be able to look at a link budget and a channel's SNR and reason about which modulation and coding choices are realistic for it — the exact judgment Module 8's cellular architecture and Module 10's RF system design content both build directly on top of.