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Wireless Fundamentals Lesson 1 Bellevue Community College Bob Young, Instructor.

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Presentation on theme: "Wireless Fundamentals Lesson 1 Bellevue Community College Bob Young, Instructor."— Presentation transcript:

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2 Wireless Fundamentals Lesson 1 Bellevue Community College Bob Young, Instructor

3 What is a radio wave? Voltage Current Sine Wave Phase Relationships

4 Radio Wave / RF Energy (a) FCC Frequency Allocations Radiation Propagation Path Loss (distance factors) Path Loss (environmental factors)

5 Radio Wave / RF Energy (b) Fading (multipath) Fading (Rayleigh) Fresnel Zone Wavelength Diversity Receivers

6 Fresnel Zone

7 The formula for calculating the 1st Fresnel Zone is: _____________ F 1 = 72.1  d 2 / (f * D) F 1, = 1st Fresnel Zone radius in feet d = midway distance in miles f = frequency in GHz. D = total distance in miles between antennas Then the 0.6F = F 1 x O.6

8 How big is the Fresnel zone? For a 5 mile link using 915 MHz 60% of the first Fresnel zone at its widest point (middle of the path) is: 50.5627835662477 feet. For a 5 mile link using 2.4 GHz 60% of the first Fresnel zone at its widest point (middle of the path) is: 31.220215806429 feet.

9 Properties of the Fresnel Zone The higher the frequency – The narrower the Fresnel zone.

10 Properties of the Fresnel Zone The longer the path – The wider the Fresnel zone.

11 4. Decibels Power Voltage RF Applications Audio Applications

12 The Gain/Loss Formula dB = 10Log 10 (P out /P in )

13 Converting dB to Gain Factor GF =10 (dB/10) (Uses the 10 x function on calculator)

14 5a. Modulation Carrier (definition) Information (definition) Analog Modulation Amplitude Modulation (AM) Frequency Modulation (FM) Pulse Modulation (PM) (ICW)

15 5b. Amplitude Modulation

16 5c. Modulation Digital Modulation Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Amplitude Shift Keying (ASK)

17 6. Transmitter Audio Processor Modulator RF Amplifier

18 7a. Receiver RF Amplifier (terminology note: misuse of term, “pre-amplifier”) Demodulator (Detector, Discriminator) Audio Processor Pre-emphasis and De-emphasis

19 7b. AM Receiver

20 8a. Interference Types of Interference Co-channel Adjacent Channel Intermodulation

21 8b. Interference Receiver Solutions to Interference Superheterodyne Receivers Image Frequency Dual Conversion Superheterodyne Receivers

22 8c. Interference Cavity and Filter Solutions to Interference Bandpass Cavities High Pass Filters Low Pass Filters Block Filters Notch Reject Filters LC Filters Crystal Filters

23 9. Antennas Types Polarization Bandwidth Gain

24 10. Transmission Line Types Loss Characteristics Bending Radius Pressurized Transmission Line

25 10a. Other Devices Transmitter Combiner Receiver Multicoupler Splitter Duplexer Leaky Coax Bi-directional Amplifier (BDA) Isolator

26 11a. Applications & Principles Broadcast Radio Television Microwave Networks Satellite Communications

27 11b. Applications & Principles RADAR Wireless LAN, 802.11 Trunked Radio Systems Wireless Data and Internet Telemetry


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