11.4 Optical Fiber, Microwave, Satellite & Philippine NTC Regulations

PRC Electronics Engineering Licensure Examination Study Guide Exam

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1 Chapter 1: Introduction & Board Exam Strategy

1.1 PRC ECE Licensure Exam Overview & Regulation 1.2 Table of Specifications & Exam Strategy

2 Chapter 2: Mathematics Foundations

2.1 College & Advanced Algebra 2.2 Trigonometry & Solid Mensuration 2.3 Analytic Geometry & Differential Calculus 2.4 Integral Calculus & Applications

3 Chapter 3: Advanced Mathematics for ECE

3.1 Differential Equations & Circuit Transients 3.2 Complex Numbers & Laplace Transforms 3.3 Fourier Series, Fourier Transforms & Z-Transforms 3.4 Vector Analysis, Matrices & Probability

4 Chapter 4: GEAS - Engineering Sciences & Economics

4.1 Engineering Physics & Materials Chemistry 4.2 Engineering Mechanics & Strength of Materials 4.3 Engineering Economics & Financial Analysis 4.4 Computer Fundamentals & C/C++ Programming

5 Chapter 5: GEAS - Management, Materials, Environment & CAD

5.1 Engineering Management & Technopreneurship 101 5.2 Materials Science & Engineering 5.3 Environment Science & Engineering 5.4 Computer-Aided Drawing (CAD) & Engineering Graphics

6 Chapter 6: GEAS - ECE Laws, Ethics & Contracts

6.1 Republic Act No. 9292 (Electronics Engineering Law of 2004) 6.2 ECE Code of Ethics & Professional Conduct 6.3 Contracts, Specifications & National Building Code (PD 1096)

7 Chapter 7: Electronics Engineering - Circuits & Semiconductor Diodes

7.1 DC & AC Circuit Analysis & Network Theorems 7.2 Electromagnetics & Passive Components 7.3 Semiconductor Physics & Diode Circuits 7.4 Power Supply Design & Voltage Regulators

8 Chapter 8: Electronics Engineering - Transistors & Analog Circuits

8.1 BJT Operation, Biasing & Small-Signal Amplifiers 8.2 FET Characteristics, Biasing & Amplifier Circuits 8.3 Multistage Amplifiers, Frequency Response & Power Amplifiers 8.4 Operational Amplifiers & Active Filter Design

9 Chapter 9: Electronics Engineering - Digital Electronics & Control Systems

9.1 Feedback Topologies & Oscillator Circuits 9.2 Boolean Algebra, Logic Gates & Combinational Circuits 9.3 Sequential Logic, Flip-Flops & Microprocessor Architecture 9.4 Industrial Power Electronics & Control System Theory

10 Chapter 10: EST - Communications Fundamentals & Transmission Lines

10.1 Signal Fundamentals, Decibel Calculations & Noise Analysis 10.2 Amplitude Modulation (AM) Principles & Receivers 10.3 Frequency Modulation (FM), Phase Modulation & Discriminators 10.4 Transmission Line Parameters, SWR & Smith Chart

11 Chapter 11: EST - Digital Communications, Wireless & Optical Systems

11.1 Pulse & Digital Modulation Systems 11.2 Data Communications, OSI Model & Protocols 11.3 Antenna Principles & Electromagnetic Wave Propagation 11.4 Optical Fiber, Microwave, Satellite & Philippine NTC Regulations

11.4 Optical Fiber, Microwave, Satellite & Philippine NTC Regulations

Key Takeaways Explain This Topic AI

Numerical Aperture (NA) of an optical fiber quantifies light-gathering ability: NA = sqrt(n1^2 - n2^2) = n1 * sqrt(2*delta).

Single-mode optical fiber attenuation reaches its minimum operating loss of ~0.2 dB/km at the 1550 nm telecommunications window.

Geostationary Earth Orbit (GEO) satellites orbit at an altitude of approximately 35,786 km directly above the equator with a 24-hour orbital period.

Satellite and microwave link budgets compute Carrier-to-Noise Ratio (C/N) by combining EIRP, Free-Space Path Loss, Receiver Figure of Merit (G/T), and system bandwidth.

Republic Act No. 7925 and NTC Memorandum Circulars regulate Philippine radio spectrum allocations, equipment type approvals, and telecom licensing.

Last updated: July 2026

11.4 Optical Fiber, Microwave, Satellite & Philippine NTC Regulations

Quick Answer: Optical fiber, microwave links, satellite systems, and NTC regulations form the core of modern telecommunications infrastructure. Key PRC licensure formulas include optical Numerical Aperture ( N A = n 1 2 − n 2 2 NA = \sqrt{n_1^2 - n_2^2} N A = n 1 2 ​ − n 2 2 ​ ​ ), GEO satellite altitude ( 35 , 786 km 35,786 \text{ km} 35 , 786 km ), link budget Carrier-to-Noise ratio ( C / N = E I R P − F S P L + G / T − k − B C/N = EIRP - FSPL + G/T - k - B C / N = E I RP − FSP L + G / T − k − B ), and compliance with Philippine Republic Act No. 7925.

Principles of Fiber Optic Communications

Fiber optic communication transmits information as light pulses along ultra-pure silica glass or plastic fibers. Light guidance is governed by Total Internal Reflection (TIR) at the interface between two optical media:

Core: Inner glass region possessing a higher refractive index n 1 n_1 n 1 ​ .

Cladding: Outer glass layer possessing a slightly lower refractive index n 2 n_2 n 2 ​ ( n 1 > n 2 n_1 > n_2 n 1 ​ > n 2 ​ ). Light Ray (Total Internal Reflection)

• ┌────────────────────────────────────────┐
• Cladding (n2) │ │
• ───────────────────┴───╲────────────────╲───────────────────┴───
• ╲ θi ╲
• Core (n1 > n2) ------ ╲----------------╲ --------------------
• ╲ ╲
• ───────────────────┬───────╲────────────────╲───────────────┬───
• Cladding (n2) │ ╲ │
• └────────────────────────────────────────┘
• Snell's Law & Critical Angle ( θ c \theta_c θ c ​ )

According to Snell's Law of Refraction ( n 1 sin ⁡ θ 1 = n 2 sin ⁡ θ 2 n_1 \sin \theta_1 = n_2 \sin \theta_2 n 1 ​ sin θ 1 ​ = n 2 ​ sin θ 2 ​ ), light striking the core-cladding boundary at an angle of incidence greater than the critical angle θ c \theta_c θ c ​ undergoes total internal reflection: sin ⁡ θ c = n 2 n 1 ⟹ θ c = arcsin ⁡ ( n 2 n 1 ) \sin \theta_c = \frac{n_2}{n_1} \implies \theta_c = \arcsin\left(\frac{n_2}{n_1}\right) sin θ c ​ = n 1 ​ n 2 ​ ​ ⟹ θ c ​ = arcsin ( n 1 ​ n 2 ​ ​ )

Numerical Aperture & Light Acceptance Angle

The Acceptance Angle ( θ a \theta_a θ a ​ ) is the maximum semi-angle of the light cone entering the fiber core from air ( n 0 ≈ 1.0 n_0 \approx 1.0 n 0 ​ ≈ 1.0 ) that will undergo total internal reflection inside the fiber.

Numerical Aperture (NA) Formula

Numerical Aperture ( N A NA N A ) measures the light-gathering capability of an optical fiber: N A = sin ⁡ θ a = n 1 2 − n 2 2 = n 1 2 Δ NA = \sin \theta_a = \sqrt{n_1^2 - n_2^2} = n_1 \sqrt{2 \Delta} N A = sin θ a ​ = n 1 2 ​ − n 2 2 ​ ​ = n 1 ​ 2Δ ​

where Δ = n 1 − n 2 n 1 \Delta = \frac{n_1 - n_2}{n_1} Δ = n 1 ​ n 1 ​ − n 2 ​ ​ is the fractional refractive index difference.

Optical Fiber Types & Transmission Characteristics

Fiber Type Core Diameter Cladding Diameter Propagation Characteristics Primary Application

Step-Index Single-Mode (SMF) 8 − 10 μ m 8 - 10 \ \mu\text{m} 8 − 10 μ m 125 μ m 125 \ \mu\text{m} 125 μ m Only fundamental mode ( L P 01 LP_{01} L P 01 ​ ) propagates. Zero modal dispersion. Long-haul telecommunications, submarine cables

Step-Index Multimode (MMF) 50 − 62.5 μ m 50 - 62.5 \ \mu\text{m} 50 − 62.5 μ m 125 μ m 125 \ \mu\text{m} 125 μ m Multiple light paths propagate. High modal dispersion. Short-distance LANs, data centers

Graded-Index Multimode (GRIN) 50 − 62.5 μ m 50 - 62.5 \ \mu\text{m} 50 − 62.5 μ m 125 μ m 125 \ \mu\text{m} 125 μ m Parabolic core index profile bends rays smoothly, equalizing travel times. Campus backbones, enterprise networks

• Attenuation & Dispersion in Optical Fibers
• Optical Attenuation Windows

Fiber loss is expressed in decibels per kilometer ( dB/km \text{dB/km} dB/km ):

850 nm Window (1st Window): High attenuation ( ≈ 2.5 − 3.5 dB/km \approx 2.5 - 3.5 \text{ dB/km} ≈ 2.5 − 3.5 dB/km ); used for low-cost LED/multimode short-reach systems.

1310 nm Window (2nd Window): Attenuation drops to ≈ 0.35 dB/km \approx 0.35 \text{ dB/km} ≈ 0.35 dB/km ; point of zero material dispersion for standard SMF.

1550 nm Window (3rd Window): Minimum attenuation window ( ≈ 0.20 dB/km \approx 0.20 \text{ dB/km} ≈ 0.20 dB/km ); standard for long-haul Dense Wavelength Division Multiplexing (DWDM) networks using Erbium-Doped Fiber Amplifiers (EDFA).

Optical Dispersion

Modal Dispersion: Occurs only in multimode fibers due to differing path lengths of light modes.

Chromatic Dispersion: Pulse broadening in single-mode fibers caused by wavelength-dependent propagation velocities. Sum of Material Dispersion and Waveguide Dispersion.

Terrestrial Microwave Communications

Terrestrial microwave links operate in the 2 GHz − 40 GHz 2 \text{ GHz} - 40 \text{ GHz} 2 GHz − 40 GHz frequency range over line-of-sight paths ( 30 − 50 km 30 - 50 \text{ km} 30 − 50 km per hop).

Fresnel Zone Clearance

To avoid diffraction loss from terrain obstacles, the First Fresnel Zone ( R 1 R_1 R 1 ​ ) must remain at least 60 % 60\% 60% unobstructed: R 1 = 17.3 d 1 ⋅ d 2 f GHz ⋅ D (meters) R_1 = 17.3 \sqrt{\frac{d_1 \cdot d_2}{f_{\text{GHz}} \cdot D}} \quad \text{(meters)} R 1 ​ = 17.3 f GHz ​ ⋅ D d 1 ​ ⋅ d 2 ​ ​ ​ (meters)

where d 1 , d 2 d_1, d_2 d 1 ​ , d 2 ​ are distances from path ends to obstacle (km), D D D is total path length (km), and f f f is frequency (GHz).

Satellite Communications & Orbital Physics

Communication satellites act as high-altitude microwave relay stations receiving uplink signals, shifting frequencies via transponders , and retransmitting downlink signals. ┌─────────────────────────┐

• │ GEO Satellite │
• │ Altitude: 35,786 km │
• └───────────┬─────────────┘
• ▲ │
• Uplink │ │ Downlink
• (e.g., 6 GHz) │ (e.g., 4 GHz)
• │ ▼
• ┌─────┴──┐ ┌───┴────┐
• │ Earth │ │ Earth │
• │ Station│ │ Station│
• └────────┘ └────────┘
• Satellite Orbits

Low Earth Orbit (LEO): Altitude 160 − 2000 km 160 - 2000 \text{ km} 160 − 2000 km . Fast orbital period ( 90 − 120 mins 90 - 120 \text{ mins} 90 − 120 mins ). Requires satellite constellations (e.g., Starlink).

Medium Earth Orbit (MEO): Altitude 2000 − 35 , 786 km 2000 - 35,786 \text{ km} 2000 − 35 , 786 km . Used for GPS navigation constellations ( 20 , 200 km 20,200 \text{ km} 20 , 200 km ).

Geostationary Earth Orbit (GEO): Positioned directly over the equator at an altitude of exactly 35 , 786 km 35,786 \text{ km} 35 , 786 km (orbital radius R = 42 , 164 km R = 42,164 \text{ km} R = 42 , 164 km ). Orbital period equals Earth's rotational period ( 23 hours 56 mins 4 secs 23 \text{ hours } 56 \text{ mins } 4 \text{ secs} 23 hours 56 mins 4 secs ), making the satellite appear stationary from ground stations. 3 GEO satellites spaced 120 ∘ 120^\circ 12 0 ∘ apart provide complete global coverage (excluding polar regions).

Satellite Link Budget Analysis & Calculation

A Link Budget tabulates all power gains and losses from transmitter to receiver.

Effective Isotropically Radiated Power (EIRP): E I R P dBW = P t , dBW + G t , dBi − L t , dB EIRP_{\text{dBW}} = P_{t,\text{dBW}} + G_{t,\text{dBi}} - L_{t,\text{dB}} E I R P dBW ​ = P t , dBW ​ + G t , dBi ​ − L t , dB ​

Receiver Figure of Merit ( G / T G/T G / T ): Ratio of receive antenna gain to system noise temperature in Kelvin ( K K K ): ( G / T ) dB/K = G r , dBi − 10 log ⁡ 10 ( T sys ) (G/T)_{\text{dB/K}} = G_{r,\text{dBi}} - 10 \log_{10}(T_{\text{sys}}) ( G / T ) dB/K ​ = G r , dBi ​ − 10 lo g 10 ​ ( T sys ​ )

Carrier-to-Noise Ratio ( C / N C/N C / N ): C / N dB = E I R P dBW − F S P L dB + ( G / T ) dB/K − k dBW/(Hz K) − B dB-Hz C/N_{\text{dB}} = EIRP_{\text{dBW}} - FSPL_{\text{dB}} + (G/T)_{\text{dB/K}} - k_{\text{dBW/(Hz K)}} - B_{\text{dB-Hz}} C / N dB ​ = E I R P dBW ​ − FSP L dB ​ + ( G / T ) dB/K ​ − k dBW/(Hz K) ​ − B dB-Hz ​ where k = 10 log ⁡ 10 ( 1.38 × 10 − 23 ) = − 228.6 dBW/(Hz ⋅ K) k = 10 \log_{10}(1.38 \times 10^{-23}) = -228.6 \text{ dBW/(Hz}\cdot \text{K)} k = 10 lo g 10 ​ ( 1.38 × 1 0 − 23 ) = − 228.6 dBW/(Hz ⋅ K) is Boltzmann's constant, and B B B is channel bandwidth.

Step-by-Step Link Budget Example

Problem: A GEO satellite downlink operates at 4 GHz 4 \text{ GHz} 4 GHz with an E I R P = 40 dBW EIRP = 40 \text{ dBW} E I RP = 40 dBW . The free-space path loss is 196 dB 196 \text{ dB} 196 dB , receiver figure of merit G / T = 20 dB/K G/T = 20 \text{ dB/K} G / T = 20 dB/K , and channel bandwidth is 36 MHz 36 \text{ MHz} 36 MHz ( 75.56 dB-Hz 75.56 \text{ dB-Hz} 75.56 dB-Hz ). Calculate the received Carrier-to-Noise ratio ( C / N C/N C / N ).

Solution: C / N = E I R P − F S P L + ( G / T ) − k − B C/N = EIRP - FSPL + (G/T) - k - B C / N = E I RP − FSP L + ( G / T ) − k − B C / N = 40 − 196 + 20 − ( − 228.6 ) − 75.56 C/N = 40 - 196 + 20 - (-228.6) - 75.56 C / N = 40 − 196 + 20 − ( − 228.6 ) − 75.56 C / N = − 136 + 228.6 − 75.56 = 17.04 dB C/N = -136 + 228.6 - 75.56 = 17.04 \text{ dB} C / N = − 136 + 228.6 − 75.56 = 17.04 dB

Philippine NTC Regulations & Telecommunications Laws

Telecommunications in the Philippines is regulated by the National Telecommunications Commission (NTC) , an agency attached to the Department of Information and Communications Technology (DICT).

Summary of Core Philippine Telecom Regulations

Law / Regulation Title / Scope Key Provisions & Impact on ECE Practice

Republic Act No. 7925 Public Telecommunications Policy Act of the Philippines Defines telecommunications entities (LTE, VAS, IXC), deregulates rates, promotes competition, and mandates ECE professional oversight

Republic Act No. 9292 Electronics Engineering Law of 2004 Mandates that ECE licensed engineers design, sign, and seal plans for telecom, broadcast, microwave, and satellite installations

NTC MC No. 03-03-2005 Spectrum Allocation & Type Approval Regulations governing type approval / acceptance of RF equipment and radio transmitter licensing

NTC MC No. 01-08-2012 Quality of Service (QoS) Standards Mandates minimum broadband speeds and cellular call drop rates ( < 2 % < 2\% < 2% ) for Philippine Telecommunications Entities (PTEs)

NTC Frequency Allocation Philippine Radio Frequency Allocation Table (PRFAT) Aligns Philippine frequency spectrum (700 MHz, 2.1 GHz, 3.5 GHz) with ITU Region 3 standards for 4G/5G deployments