COURSE ON COMMUNICATION ELECTRONICS - SPRING SEMESTER 2021/22
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16.2.2022 - Lecture 1: Range and capacity of wired and wireless links
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1. Shannon's theorem for information transfer in the presence of noise.
2. Capacity of a bandwidth-limited link.
3. Natural sources of electronics/radio/optical noise.
4. Capacity of a power-limited link as a function of bandwidth.
5. Capacity of a bandwidth-limited link as a function of signal power.
6. Practical example: capacity of an analog-telephone-line modem.
7. Equivalent circuit of a coaxial-cable link.
8. Evolution of optical-fiber links.
9. Attenuation of a silica-glass optical fiber.
10. Free-space electromagnetic wave propagation.
11. Near and far fields of radio devices.
12. Atmospheric transmission windows.
13. Comparison of wired and wireless links.


21.2.2022 - Lecture 2: Telegrapher's equations
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1. Derivation of telegrapher's equations in time domain.
2. Voltage solution in loss-less time domain.
3. Characteristic resistance of a loss-less transmission line.
4. Load reflection coefficient, relationship with resistance.
5. Reflectometer bridge: schematic, equations, operation.
6. Unterminated (open) line ringing, lumped equivalent.
7. Ringing suppression with source termination.
8. Ringing suppression with load termination.
9. Source termination in unidirectional and bidirectional buses.
10. Load termination in ECL circuits.
11. Absence of termination in RS232 communications, unbalanced line.
12. Source termination in USB high-speed 12Mbps.
13. Source and load termination in 100Mbit/s Ethernet.
14. Bidirectional transmission in 1Gbit/s Ethernet using bridges.
15. General solution in frequency domain, angular wavenumber, characteristic impedance.
16. Low but nonzero loss in frequency domain, phase and attenuation constants.
17. Example: fields and characteristic impedance of a coaxial cable.
18. Example: attenuation of a coaxial cable in Np/m and dB/m.
19. Coax design parameters: permittivity, diameter, ratio x=b/a. 
20. Example: coax attenuation versus b/a, higher-order modes limit.
21. Characteristic impedance, complex reflection, impedance transformation.
22. Calculations using the Smith chart.
23. Forward and reflected power, standing wave energy.
24. Voltage standing-wave ratio on loss-less lines.
25. Animation: forward wave only on loss-less and lossy line.
26. Animation: forward, reflected and standing waves on loss-less lines.
27. Animation: forward, reflected and standing waves on lossy lines.
28. Scattering parameters: definition of reflection parameters s11 and s22.
29. Scattering parameters: definition of transmission parameters s12 and s21.


28.2.2022 - Lecture 3: Optical-fiber communications
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1. Communications using silica-glass optical fibers.
2. Bending loss of a dielectric waveguide due to tunnelling.
3. Cabling of optical fibers, tight and loose secondary coatings.
4. Equivalent circuit of a dielectric, resonance losses.
5. Complex refraction index of silica (SiO2) glass.
6. Rayleigh scattering on particles in silica glass.
7. Fiber attenuation due to glass resonances, scattering and impurities.
8. Relative index difference, numerical aperture and cone of acceptance.
9. Multipath (multimode) dispersion in an optical fiber.
10. Mitigating multimode dispersion with a graded-index core.
11. Transversal phase resonance in a 1D dielectric waveguide.
12. Effects of the first few modes in a 1D planar dielectric waveguide.
13. Mode fields: standing wave in the core, exponential decay in the cladding.
14. Fiber 2D cylindrical dielectric waveguide modes.
15. Comparison of waveguide effects in planar and cylindrical waveguides.
16. Refraction index, phase and group velocity from Sellmeier's equation for SiO2.
17. Fiber chromatic dispersion including material and waveguide effects.
18. Examples of chromatic-dispersion limits in simple optical links. 
19. Evolution of dispesion-shifted fibers.
20. Chromatic dispersion in trans-oceanic links, inter-city links and local networks.
21. Polarization-mode dispersion before and after introducing spun fibers.
22. Comparison of different dispersions: multimode, chromatic, polarization.
23. Power density and electric field in optical fibers, practical power limits.
24. Electrostriction effect in arbitrary materials and silica glass.
25. Brillouin scattering and Raman scattering in optical fibers.
26. Four-wave mixing or intermodulation distortion in optical fibers.
27. Effective length of FWM due to attenuation and phase mismatch.
28. Evolution of effectine length, Pip3 and capacity of trans-oceanic cables.


8.3.2022 - Lecture 4: Antennas and propagation of electromagnetic waves
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1. Cartesian and spherical coordinates, unit vectors, conversions.
2. Maxwell equations in differential form, special relativity effects.
3. Wave equations for potentials, wavenumber, field calculations from potentials.
4. Reactive near field and radiation from a small electric dipole.
5. Radiation resistance of an antenna.
6. Reactive near field and radiation from a small magnetic dipole.
7. Multiturn-loop antenna and ferrite antenna.
8. Near-field communications with small loop antennas.
9. Radiation efficiency, directivity, gain and EIRP of a directional transmitter.
10. Directivity for arbitrary radiation patterns.
11. Coherent versus non-coherent transmission and reception with examples.
12. Friis equation of a radio link with coherent antennas.
13. Application of the Friis equation to nondirectional, broadcast and point-to-point links.
14. Rayleigh distance in photography and antenna far field: pattern, directivity, gain.
15. Half-wave dipole directivity, radiation resistance and efficiency.
16. Aperture radiation, calculation of directivity, effective area and illumination efficiency.
17. Aperture antennas: phased array, mirror, lens, horn, slow-wave structures.
18. Slow-wave structures: Yagi-Uda rods, crossed rods, loops, disks, helix.
19. Fresnel ellipsoids and Fresnel zones for radio and optics.
20. Knife-edge diffraction on a mountain ridge, Fresnel integral.
21. Approximation of the magnitude of the Fresnel integral.
22. Specular ground reflection, attenuation due to interference.
23. Attenuation from urban-environment measurements.
24. Earth's-atmosphere composition and attenuation in the microwave region.
25. Refraction and total reflection in the presence of temperature inversion.
26. Other sorces of attenuation, refraction and reflection in the atmosphere..


14.3.2022 - Lecture 5: Semiconductor devices for communications - diodes
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1. First radio receivers cca 1920.
2. Bandgap, dielectric strength and carrier mobilities of different semiconductors.
3. Diode equation, thermal voltage ans diode ideality factor.
4. Replacing Is with U1mA (barrier voltage).
5. Diode curves for reverse and forward bias.
6. Thermal coefficients of voltage drops.
7. Diode symbols and package markings.
8. Linear, abrupt and hyperabrupt doping profiles of varactors diodes.
9. Semiconductor type and polarity choices for varactors.
10. Hyperabrupt-varactor depletion region at different reverse bias. 
11. Varactor tuning of resonant circuits.
12. Differential diode admittance and impedance, charge-storage efffects.
13. Design of different Schottky diodes: point-contact, RF and guard-ring.
14. Schottky/back RF diode detector performance.
15. Design of different PIN diodes: limiter, switch and variable resistor.
16. RF switches using series and shunt PIN diodes.
17. Operation of Gunn elements as transferred-electron devices (TED).
18. Frequency limits of PN-junction and Schottky/back diodes.
19. PIN photodiode design for fiber-optic comunications.
20. Avalanche photodiodes with built-in amplification, receiver-sensitivity improvements.
21. Spontaneous emission of light from semiconductors.
22. Design of a communications light-emitting diode.
23. Stimulated emission of light from semiconductors.
24. Design of a longitudinal Fabry-Perot semiconductor laser.


21.3.2022 - Lecture 6: Semiconductor devices for communications - transistors
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1. First germanium PNP transistors.
2. Common-base amplifier with a low-performance PNP transistor, parameter alpha.
3. Voltage gain and power gain of a common-base amplifier in class A.
4. Planar silicon bipolar transistors NPN and PNP.
5. Common emitter current gain beta.
6. NPN and PNP bipolar transistor responses.
7. Common-emitter amplifier in class A, current, voltage and power gains.
8. Common-collector amplifier or emitter follower.
9. Common-emitter bias circuits, transistor tolerances and thermal runaway.
10. Current gain versus frequency, charge-storage effects and transition frequency.
11. Effects of base resistance, current shift, decay of beta and Ft.
12. Secondary breakdown in bipolar transistors, emitter ballast resistors.
13. Design of RF power bipolar transistors with emitter fingers.
14. Evolution of field-effect transistors.
15. Silicon junction FETs and insulated-gate MOSFETs.
16. Responses of JFETs and MOSFETs of both polarities, practical devices?
17. Limitation of the gate drive for JFETs and MESFETs.
18. Pinch-off voltage for JFETs and MOSFETs.
19. Design of power MOSFETs for low frequencies and RF.
20. Input (gate) protection diodes for MOSFETs and CMOS logic.
21. Side effects of protection diodes?
22. Small-signal GaAs MESFET, design and electrical response.
23. High-electron-mobility transistor (HEMT) from GaAs and InP.
24. Responses of depletion-mode and enhancement-mode HEMTs.
25. Design and performance of power GaN HEMTs.


28.3.2022 - Lecture 7: Noise in electronics
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1. Dispute between famous scientists, noise in natural laws.
2. Noise in wireless and wired communications.
3. Spectral density of natural noise: thermal noise and shot noise.
4. Noise in electronics, radio and optics, crossover at 6THz.
5. Planck law of blackbody radiation, spectral brightness.
6. Rayleigh-Jeans approximation, two polarizations, UV catastrophe.
7. Noise power establishes thermal equilibrium, antenna radiation resistance.
8. Johnson-Nyquist noise in electronics versus Planck and Rayleigh-Jeans.
9. Natural noise sources, reflectivity of different targets, antenna temperature.
10. Sky noise including galactic sources and atmosphere attenuation.
11. Equivalent noise temperature of an amplifier referenced to the input.
12. Summation of noise powers/temperatures in an amplifier chain. 
13. Noise temperature of an infinite chain of identical amplifiers.
14. Historical reasons for the nonsense definition of the noise figure, textbook errors.
15. Sensible definition of the noise figure, agreed reference temperature 290K.
16. Nomograph and formulas for converting between noise figure and noise temperature.
17. Simple example: sensitivity of GSM phone, Ta=To.
18. Example satellite TV: Ta much smaller than To.
19. Example HF receiver: Ta much larger than To.
20. Attenuator in front of an amplifier, calculation of the nose figure, practical examples.
21. G/T ratio of a satellite groundstation, selecting dish illumination for G and Ta.
22. Gain, noise temperature and noise figure of practical amplification devices.
23. Noise parameters of an active device, effects of impedance mismatch.
24. Hot/cold method for measuring the noise temperature/figure, practical noise sources.
25. Noise-figure meter without and with calibration.


2.4.2022 - Lecture 8: Analog filters in frequency domain
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1. Applications of frequency-domain analog filters.
2. LC tuned circuit as electrical resonator: energy, losses and Q.
3. Q of lumped-component LC, coaxial resonator, rectangular resonator, quartz crystal.
4. Definition of unloaded Q and loaded Q of a resonator.
5. -3dB bandwidth versus loaded Q of a single-resonator filter.
6. Impedance matching, transmission and passband insertion loss from Ql/Qu.
7. Group delay of a single-resonator passband filter.
8. Characteristic impedance of a ladder from reactive components, T and pi elements.
9. Passband Re[Zk] and stopband Im[Zk] of a ladder filter, rectangular impossible.
10. Lowpass and highpass T elements, cutoff frequencies, Zk plots.
11. General bandpass T element, four variables for three parameters, non-implementable L.
12. Sensible choice for BPF: L1/L2=C2/C1, central frequency, non-implementable L, Zk plot.
13. Replacing non-implemetable serial L with parallel L and impedance inverters.
14. BPF T element with serial capacitors only, impedance plot.
15. Example: coaxial cavity for 450MHz with adjustable frequency and coupling.
16. Interdigital cavity filters and comb catity filters.
17. Example: comb bandpass duplexer for 3.4GHz, adjustable frequencies and couplings.
18. Example: comb bandpass for 400MHz with adjustable inductive couplings.
19. Example: electrical silver-plated ceramic comb filters and resonators.
20. General bandstop T element, four variables for three parameters, non-implementable inductors.
21. Sensible choice for BSF: L1/L2=C2/C1, central frequency, non-implementable inductors, Zk plot.
22. Practical implementation of BSFs with transmission-line impedance inverters and resonators.
23. Example: combined BSF-BPF GSM duplexer with lambda/4 impedance inverters.
24. Example: microstrip BSF for GPS C/A signal at 1575.42MHz.
25. Microstrip resonators, material properties, interdigital, comb, lambda/2 straight and folded.
26. Example: microstrip interdigital BPFs for 1.3GHz and 2.3GHz, enclosure resonances.
27. Example: microstrip lambda/2 straight BPF for 8GHz-12.5GHz.
28. Example: microstrip lambda/2 folded BPFs for 1.9GHz, 2.3GHz, 2.9GHz and 3.4GHz, enclosure resonances.
29. Improving ladder-filter input/output impedance matching, problems with filter concatenation.


9.4.2022 - Lecture 9: Piezoelectric devices
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1. Communication-electronics roles of silicon.
2. Effects of resonator Q on the oscillator phase noise.
3. Phase-noise constrainst in analog and digital radio communications.
4. History of quartz in electronics.
5. Mechanical waves: pressure, shear and surface.
6. Different piezoelectric devices.
7. Properties of natural quartz crystal.
8. Historical quartz resonator FT243.
9. Hydrothermal growth of synthetic quartz crystals.
10. Artificial quartz crystal.
11. Different quartz-crystal cuts.
12. Finding the crystal axes with X rays.
13. Oscillation modes of quartz-crystal plates.
14. Modern AT-cut quartz-crystal plates with electrodes and hoders.
15. AT-plate shear oscillation modes.
16. AT-plate equivalent electric circuit.
17. AT-plate admittance including fundamental, 3rd, 5th and 7th overtones.
18. AT-plate oscillation modes (anharmonics).
19. Electrical response of AT-plate anharmonics.
20. AT-plate temperature-frequency dependence.
21. AT-plate cross-sections.
22. Side effects of plated electrodes.
23. Modern AT-plate crystal holder.
24. Examples: modern piezoelectric-resonator housings.
25. Crystal oscillators.
26. Sticking-dirt temperature hysteresis.
27. Adjustable crystal oscillators VXO, VCXO, TCXO.
28. Crystal bandpass filters (IIR): bridge, ladder, monolithic.
29. Quartz-crystal specification.
30. Piezoceramic resonators, bandpass and bandstop filters.
31. Film bulk-acoustic resonator (FBAR) technologies.
32. FBAR ladder bandpass filters, fighting anharmonics.
33. Travelling-wave SAW bandpass filter (FIR)
34. Example: SAW filter for 36MHz.
35. Standing-wave SAW resonator.


16.4.2022 - Lecture 10: Transmitters and receivers
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1. Hertz experiments.
2. Four tuned circuits (Nikola Tesla).
3. Evolution of radio receivers.
4. Super-regenerative receiver.
5. Heterodyne AM receiver.
6. Analog multiplier as frequency mixer.
7. Single-diode mixer.
8. Single-balanced mixers: diode pair, JFET, HEMT, differential BJT.
9. Double-balanced mixers: diode ring, EXOR gate, Gilbert cell.
10. Image-reject mixer.
11. Amplitude-modulation (speech) transmitters.
12. AM transmitter with output modulation.
13. Frequency(phase)-modulated transmitter.
14. Heterodyne FM receiver.
15. Single-sideband AM with suppressed carrier.
16. Output/input analog signal/noise ratio.
17. SSB transmitter with image rejection.
18. SSB receiver with image rejection.
19. Quadrature amplitude modulation (QAM).
20. Weaver SSB transmitter.
21. Weaver SSB receiver.
22. Zero-IF QAM receiver.
23. Zero-IF receiver AD8347.
24. Dual-polarization (MIMO) lightwave receiver.


25.4.2022 - Lecture 11: Numerical modulations
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1. Numerical radio link.
2. Historical patching: modem radio link.
3. Modulation constellation, symbols=phasors.
4. Bi-Phase Shift Keying (BPSK).
5. Quadri-Phase Shift Keying (QPSK).
6. Quadrature Amplitude Modulation (QAM).
7. Different versions of PSK and QAM.
8. PSK and/or QAM spectrum shaping.
9. (Gaussian) Minumum Shift Keying (MSK/GMSK).
10. Multipath workaround with an equalizing filter.
11. Spreat-spectrum communications and Code-Division Multiple Access?
12. Multipath mitigation with multitone transmission.
13. Orthogonal Frequency Division Multiplex (OFDM).
14. Properties of an OFDM transmission.
15. Errror Vector Magnitude (EVM) and Mudulation Error Ratio (MER).
16. Bit-Error Rate (BER) calculation for BPSK example.
17. BER table for BPSK.
18. BER plots for BPSK, QPSK, 16-QAM, 64-QAM versus Shannon theory.
19. Forward Error Correction (FEC).
20. Linear-Feedback Shift Register (LFSR) pseudo-random sequences.
21. BER measurement using pseudo-random sequences.
22. Measured BER of a real link with imperfect hardware.


2.5.2022 - Lecture 12: Intermodulation distortion
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1. Amplifier efficiency.
2. Amplifier saturation.
3. Class A efficiency.
4. Amplifier distortion.
5. Amplifier nonlinearity.
6. Effects of polynomial terms.
7. Single-tone spectrum.
8. Dual-tone spectrum.
9. InterModulation Distortion (IMD).
10. IMD spectrum.
11. IMD3 power.
12. IMD power calculation.
13. IMD3 spectrum calculation.
14. Higher-order IMD.
15. Three-tone IMD.
16. BJT Pip3 estimate.
17. FET Pip3 estimate.
18. Analog TV transmitter example.
19. Two-tone IMD measurement.
20. Passive intermodulation (PIM) example.
21. Four-wave mixing(FWM=IMD in optical fibers).


8.5.2022 - Lecture 13: Distortion mitigation
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1. Repeat: dual-tone spectrum.
2. Repeat: IMD magnitude.
3. IMD inside an amplifier chain.
4. Amplifier-chain Pip3.
5. Improper amplifier-chain design.
6. Receiver IMD.
7. Receiver Piip3.
8. Harmful RF amplifier.
9. Doubly-balanced mixer.
10. Receiver dynamic range.
11. Amplifier class of operation.
12. Repeat: class A amplifier.
13. Class B transfer function.
14. Real class B IMD.
15. Class B amplifier for pi/4-QPSK modulation.
16. Class C amplifier.
17. Class C radio transmitters.
18. Predistortion transmitter.
19. Feed-forward amplifier.
20. Doherty amplifier.
21. AM to PM conversion.
22. Repeat: EVM and MER.
23. Peak-to-Average Power Ratio (PAPR).
24. OFDM transmitter backoff.


13.5.2022 - Lecture 14: Electronic oscillator
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1. Sinewave signal source.
2. Radio-frequency oscillators.
3. Barkhausen criterion.
4. Oscillator startup.
5. Super-regenerative receiver.
6. Different oscillator implementations.
7. Oscillator noise.
8. Amplitude and phase noise.
9. Leeson's equation.
10. Phase-noise plot versus offset from carrier.
11. Phase-noise consequences.
12. Low-frequency flicker noise.
13. Extended oscillator noise.
14. Phase-noise plot including flicker.
15. Loaded-resonator quality.
16. Phase-locked loop.
17. Derivation of the Lorentz spectral line.
18. Lorentz spectral linewidth.
19. Phase noise without approximations.
20. Oscillator versus BPF comparison.
21. Unstable saturation.
22. Klystron 2K25 Rieke diagram.
23. Magnetron 2M218 Rieke diagram.
24. Oscillator design rules.


20.5.2022 - Lecture 15: Frequency synthesizers
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1. Radio-receiver tuning.
2. Tuned-circuit frequency adjustment.
3. Analog FM transceiver (WW2).
4. Analog CB transceiver.
5. Direct digital synthesis.
6. Voltage-controlled oscillator.
7. Phase-locked loop.
8. Frequency/phase comparator.
9. Charge-pump operation.
10. Unstable phase-locked loop.
11. Stable phase-locked loop.
12. Loop-filter calculation.
13. Landing autopilot. 
14. Unstable voltage regulator.
15. Zero/pole ratio.
16. Phase-noise transfer.
17. Pll phase noise.
18. Frequency dividers.
19. Analog frequenc modulation & PLL.
20. Fractional PLL.
21. Fractional PLL ADF4351 from Analog Devices.
22. LO with ADF4351.



LAB EXPERIMENTS ON COMMUNICATION ELECTRONICS - SPRING SEMESTER 2021/22
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11.6.2022 - Radio-frequency instruments (LSO1) 
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1. Radio-frequency connectors, power meter.
2. Digital frequency counter.
3. Radio-frequency spectrum analyzer.
4. Lecher wires.

15.6.2022 - Optical-fiber communications (LSO2)
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5. Optical-fiber connectors, mode cut-off wavelengths.
6. Connector reflections and Rayleigh scattering with OTDR, SMF arc splicing.
7. Semiconductor-laser modulation response and temperature dependance.
8. BER measurement in an optical link, APD bias.

18.6.2022 - Antennas and propagation (LSO1)
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9. Measurement of the radiation pattern and directivity of an antenna.
10. Finding the focal point of a parabolic dish.
11. Knife-edge obstacle attenuation.
12. Noise temperature of the antenna, the receiver and the Sun surface.

20.6.2022 - Amplifier efficiency, noise and distortion (LSO1)
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13. Bipolar-transistor amplifier in class A, B, C and dual B.
14. Amplifier noise-figure measurement.
15. Saturation and P1dB od a transistor amplifier.
16. Class-A amplifier intermodulation third-order intercept point.

23.6.2022 - Radio-frequency circuits (LSO1)
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17. Characteristic impedance of ladder filters.
18. Quadrature mixer.
19. Microwave VCO phase noise.
20. Phase-locked-loop frequency synthesizer.


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