Signal ProcessingCommunications

Digital Modulation: ASK, FSK, PSK & QAM

How do you send a text message over invisible radio waves? By encoding 1s and 0s into patterns of wave changes — that's digital modulation.

Live Constellation Diagrams
Each dot represents a unique symbol — a distinct amplitude+phase combination that carries one or more bits. The animated jitter shows how noise displaces received symbols from their ideal positions.
IQ10

BPSK: 2 points on I-axis. Maximum noise immunity — symbols maximally separated.

Core Concepts

Quick Reference
Modulation schemes and their spectral efficiency
BPSK1 bit/symbol — GPS, satellite
QPSK2 bits/symbol — UMTS, DVB-S
16-QAM4 bits/symbol — LTE, Wi-Fi
64-QAM6 bits/symbol — LTE, cable TV
256-QAM8 bits/symbol — 5G, Wi-Fi 6
EVM formulaEVM% = (RMS error / RMS ref) × 100
Related Tools
Put these concepts to work

BER Calculator

Calculate bit error rate vs SNR for any modulation scheme

Power Converter

Convert between dBm, watts, and volts for link budget work