12007 Introduction in Telecommunication (121009) Chris Roeloffzen Chair: Telecommunication engineering (EWI) Floor 8 HOGEKAMP EL/TN building (north) Telephone

22007 Contents of the course Book: Electronic Communications Systems W. Tomasi. Prentice Hall, 5th edition, 2004 ISBN: For up-to-date information see:

32007 Contents of the course Lecture 1 - 3: Introduction Chapter 1: Introduction to Electronic Communications Chapter 2: Signal Analysis and Mixing Lecture 4 - 7: CW modulation Chapter 4: Amplitude modulation, Transmission Chapter 5: Amplitude modulation, Reception Chapter 6: Single-side banded Communication Systems Chapter 7: Angle Modulation Transmission Chapter 8: Angle Modulation Receivers Lecture : Media Chapter 12: Metallic Transmission Lines Chapter 14: Electromagnetic Wave Propagation Chapter 15: Antennas Chapter 13: Optical Fibers Lecture : Digital Communication Chapter 9: Digital Modulation Chapter 10: Digital Transmission Lecture 15 & 16: ????????????????? For specific information see:

42007 Today: Lecture 1 Chapter 1: Introduction to Electronic Communications

52007 Chapter 1 What is Telecommunication? Transmission and Networks Milestones Signal transmission and Media Modulation and Demodulation The Electromagnetic Frequency Spectrum Bandwidth and Information Capacity Noise Analysis

62007 Introduction What is Telecommunication ?????? What are the three main components in a communication system? Give some information signals Any transmission, emission, or reception of signs, signals, writing, images and sound or intelligence of any nature by wire, radio, optical or other electromagnetic systems. ITU-1989

72007 Communication Networks Point to point Mesh network

82007 Milestones Samuel Morse:1837telegraph

92007 Samuel Morse:1837telegraph Alexander Bell:1876telephone Milestones

Samuel Morse:1837telegraph Alexander Bell:1876telephone Marconi:1895wireless telegraph not the inventor of Radio Nikola Tesla<1895:Inventor of Radio Milestones

Samuel Morse:1837telegraph Alexander Bell:1876telephone Marconi:1895wireless telegraph not the inventor of Radio Nikola Tesla<1895:Inventor of Radio Lee De Forest1907:triode vacuum tube ‘Audion’ (amplifier) Milestones

Samuel Morse:1837telegraph Alexander Bell:1876telephone Marconi:1895wireless telegraph not the inventor of Radio Nikola Tesla<1895:Inventor of Radio Lee De Forest1907:triode vacuum tube 1920: Commercial AM radio broadcast Milestones

Samuel Morse:1837telegraph Alexander Bell:1876telephone Marconi:1895wireless telegraph not the inventor of Radio Nikola Tesla<1895:Inventor of Radio Lee De Forest1907:triode vacuum tube 1920: Commercial AM radio broadcast 1939: First FM radio broadcast ‘Alphine New Jersey by Edwin Armstrong Milestones

P in P out V I R What is the advantage of using dB ???????????????? Power Measurements (dB, dBm)

P in P out Power Measurements (dB, dBm)

Signal transmission (1) Information source (intelligence) TransmitterReceiver Received Information System noise and interference Transmission medium or Communications channel Copper cable (coax, UTP) Optical fiber cable Free space (Radio)

Signal transmission (2) Low-frequency source information (analog or digital) Modulator and frequency up- converter Transmission medium (channel) High- frequency oscillator Amplif ier Frequency down- converter High-frequency local oscillator Power amplifier Filter Transmitter Receiver

Transmission media and products

Adaptation to the media Reasons are a.o. Necessity:transmission frequency range Efficiency:multiplexing Quality:e.g. due to noise, interference Example: Microwave transmission of AM Radio frequency power 500 kHz power frequency Modulation

Change parameters of a carrier Information signal: A c (t) f c (t)  (t) A c (t) : amplitude modulationAM ASK f c (t) : frequency modulationFM FSK  (t) : phase modulationPM PSK A c (t) and  (t)  QAM (Digital) Modulation principle DigitalAnalog

Demodulation principle Recovering of information signal from the received modulated transmission signal Example: AM:transmitted signal Demodulation:multiply with in the receiver

Electromagnetic Frequency Spectrum Frequency : f [Hertz] Wavelength: [m] c : velocity of light: m/sec f 1 kHz  m 100 kHz  m 10 MHz  m = 30 m 1 GHz  m = 30 cm

Electromagnetic Frequency Spectrum

242007

Bandwidth and information capacity (1) Hartleys law1920 I =amount of information B =system bandwidth (Hertz) t =transmission time (seconds) The book is wrong!!!!!!

Shannon limit for information capacity I =information capacity (bits per second) B =system bandwidth (Hertz) S/N =signal-to-noise power ratio (dimensionless) Bandwidth and information capacity (2)

Example: Standard telephony B =2,7 kHz Bandwidth and information capacity

Example: Standard telephony B =2,7 kHz Bandwidth and information capacity

Noise S/N =signal-to-noise power ratio (dimensionless) With a given bandwidth a system has a larger capacity if the S/N ratio is larger In a practical system noise is always present Noise- internal (generated within the device) - external (generated outside the device)

Noise Correlated noise:Related to signal Uncorrelated noise: Not related to signal

Noise Correlated noise Nonlinear distortion Harmonic distortion Intermodulation distortion Uncorrelated noise External Atmospheric Extraterrestrial Solar Cosmic Man-made Impulse Interference Internal Thermal noise (random movement of electrons) Shot (random arrival of carriers) Transient time

Thermal Noise (white noise) N = noise power (watts) B = bandwidth (hertz) K = Boltzmann’s proportionality constant ( Joules per kelvin) T = absolute temperature (kelvin) -Random -Continuous spectral density -Additive -Present in all devices

Noise voltage

Signal-to-Noise Ratio P s = signal power (watts) P n = noise power (watts) Or expressed in decibel

Ideal amplifier A p Nonideal amplifier A p, N d Noise in Amplifier

Noise Factor and Noise Figure F = noise factor (no dimension) NF = noise figure (dB)

F T = total noise factor (dimensionless) NF T = total noise figure (dB) Noise Factor and Noise Figure of Cascade

F T = total noise factor (dimensionless) NF T = total noise figure (dB) Noise Factor and Noise Figure of Cascade

Noise Temperature T = environmental temperature (290 Kelvin) N = noise power (watts) K = Boltzmann’s constant ( J/K) B = total noise factor (hertz) T e = equivalent noise temperature T = environmental temperature (290 Kelvin) F = noise factor (dimensionless)