Modulation

/ˌmɒd.jʊˈleɪ.ʃən/

“Turning signals into messages, one wave at a time.”

Modulation is the process of embedding information onto a carrier wave by varying one or more of its fundamental properties: amplitude, frequency, or phase. It is the bridge between raw data and physical transmission, allowing digital or analog signals to traverse mediums like radio waves, optical fibers, or electrical circuits.

Quadrature Phase Shift Keying

/ˌkjuː piː ɛs keɪ/

noun … “quadrature phase shift keying.”

QPSK is a digital modulation technique that encodes two bits per symbol by varying the phase of a carrier wave among four discrete states, typically 0°, 90°, 180°, and 270°. By using four phases instead of the two in BPSK, QPSK doubles the data rate for the same bandwidth while maintaining robustness to noise and interference.

Forward Error Correction

/ˌɛf iː ˈsiː/

noun … “forward error correction.”

FEC is a communication technique that improves reliability by adding carefully structured redundancy to transmitted data, allowing the receiver to detect and correct errors without asking the sender for retransmission. The key idea is anticipation … errors are expected, planned for, and repaired locally.

Binary Phase Shift Keying

/ˌbiː piː ɛs keɪ/

noun … “binary phase shift keying.”

BPSK is a digital modulation technique that encodes binary data by shifting the phase of a carrier wave between two discrete states. Each state represents one bit … typically a phase of 0 degrees for binary 1 and 180 degrees for binary 0. Because only two phases are used, BPSK is conceptually simple, mathematically elegant, and exceptionally robust in noisy environments.

SSH

/ˌɛs ɛs ˈeɪtʃ/

noun … “a secure protocol for remote command execution and communication over untrusted networks.”