Communication Basics #20 Worked Example: ASK/FSK/PSK Plot (microsec)

Instructor: Dr. Süleyman Burak ÇELİK

Another worked example — same three digital modulation types as d19, but now 1000 times faster. We work through the problem step by step in light mode. Given a carrier described by sin(6x10^6 pi t), we first extract the carrier frequency (2pi f = 6x10^6 pi gives f = 3 MHz), determine the bit duration (1 microsecond, so 1 Mbps data rate), and count how many carrier cycles fit inside each bit. Then we draw the complete ASK, FSK, and PSK waveforms for the given bit pattern on a microsecond time axis. We finish by discussing the practical context: why a 1 Mbps channel cannot carry voice-only traffic efficiently, and what kind of signals (video, data) actually need this bandwidth. Topics covered: - carrier frequency extraction from the general formula sin(2pi f t) - 3 MHz carrier, 1 microsecond bit duration, 1 Mbps data rate - cycles per bit calculation at megahertz rates - ASK waveform drawing on microsecond scale - FSK with 3 MHz and 6 MHz carrier frequencies - PSK with 180-degree phase reversal - practical context: voice channel (64 kbps) vs video/data suitability Part of the AcEdumy Communication Basics series.