ASK FSK PSK Introduction
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This document provides an introduction to digital modulation techniques. It discusses the reasons for choosing encoding techniques and defines modulation as adding information to a carrier signal. It describes the key signal characteristics that can be modified - amplitude, frequency, and phase. It also summarizes three common digital modulation techniques: ASK uses two amplitude levels to encode bits, FSK uses two frequencies, and PSK uses two phase shifts. References for further reading are also provided.
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ASK FSK PSK Introduction
- 1. EC6651 Communication Engineering Introduction to Digital modulation techniques Prepared by, Mr.R.Deiva Nayagam, AP/ECE Ramco Institute of Technology
- 3. Reasons for choosing encoding techniques
- 4. What is modulation ? • Modulation = Adding information to a carrier signal • The sine wave on which the characteristics of the information signal are modulated is called a carrier signal
- 7. Signal characteristics that can be modified signal x(t) = A cos(2πft + Φ) • A – amplitude • f – frequency • Φ – phase (initial angle of the sinusoidal function at its origin
- 8. Modulation
- 11. ASK • ASK On-off keying (Amplitude Shift Keying) – frequency is kept constant, amplitude has 2 levels (for bit 1 and for bit 0) The binary sequence 0010110010
- 12. FSK (Frequency shift keyring)
- 13. PSK (Phase shift keyring)
- 14. References Taub & Schiling “Principles of Communication Systems” Tata McGraw Hill 2007. J.Das “Principles of Digital Communication” New Age International, 1986.