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Wireless Communication Basics. Transmitter. Receiver. RF Basics. Basic Communication System Transmitter and Receiver. Transmitter. Antenna 1. Receiver. RF Basics. Basic Communication System Transmitter and Receiver Transmitting Antenna. Transmitter. Antenna 1. Antenna 2. Receiver.

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rf basics

Transmitter

Receiver

RF Basics
  • Basic Communication System
    • Transmitter and Receiver
rf basics3

Transmitter

Antenna 1

Receiver

RF Basics

Basic Communication System

  • Transmitter and Receiver
  • Transmitting Antenna
rf basics4

Transmitter

Antenna 1

Antenna 2

Receiver

RF Basics

Basic Communication System

  • Transmitter and Receiver
  • Transmitting Antenna
  • Receiving Antenna
rf basics5

Transmitter

Antenna 1

Antenna 2

Receiver

RF Basics

Basic Communication System

  • Transmitter and Receiver
  • Transmitting Antenna
  • Receiving Antenna
  • Environment

Environment

rf basics6

Transmitter

Antenna 1

Antenna 2

Receiver

RF Basics

Maximizing Range

rf essentials

Increase Power

Antenna 1

Antenna 2

Receiver

RF Essentials

Maximizing Range

  • Increase Transmitter (TX) Power
    • Government Regulated
    • Low-powered Applications
rf essentials8

Increase

Power

Increase

Gain

Increase

Gain

Improve

RX Sensitivity

RF Essentials

Maximizing Range

  • Increase Transmitter (TX) Power
  • Increase Receiver (RX) Sensitivity
    • Specified in dBm
    • Every 6 dB doubles the range LOS
    • Every 12 dB doubles range indoors / urban environments
rf basics9

Increase

Power

Increase

Gain

Increase

Gain

Improve

RX Sensitivity

RF Basics

Maximizing Range

  • Increase Transmitter (TX) Power
  • Increase Receiver (RX) Sensitivity
  • Increase Antenna Gain
    • More gain equates with more focusing of energy
    • Antenna cables should be as short as possible
rf basics10
RF Basics

Basic Communication System

  • Transmitter and Receiver
  • Transmitting Antenna
    • Focused energy
rf basics11
RF Basics

Basic Communication System

  • Transmitter and Receiver
  • Transmitting Antenna
  • Receiving Antenna
    • Focused energy
rf basics12
RF Basics

Antenna Gain

  • Government-imposed power restrictions
  • Omnidirectional
rf basics13
RF Basics

Antenna Gain

  • Directional
rf basics14

Increase

Power

Increase

Gain

Increase

Gain

Improve

RX Sensitivity

RF Basics

Maximizing Range

  • Increase Transmitter (TX) Power
  • Improve Receiver (RX) Sensitivity
  • Increase Antenna Gain
  • Clear the Environment of obstructions
    • Visual (Linear) line-of-sight vs. RF (Radio) line-of-sight

Clear the

Environment

rf basics15

Fresnel

Zone

RF Basics

Fresnel Zone

  • Football-shaped path
rf basics16
RF Basics

Fresnel Zone

  • Football-shaped path
  • Acceptable = 60% of Zone 1 + 3 meters
  • Raise antennas to help clear the zone
rf basics17
RF Basics

Fresnel Zone

  • Football-shaped path
  • Acceptable = 60% of Zone 1 + 3 meters
  • Raise antennas to help clear the zone
  • Formula
rf basics18
RF Basics

Fresnel Zone Diameters

importance of frequency selection
Importance of Frequency Selection

Geographic Deployment

Worldwide versus Regional

RF Performance

Range

RF Penetration

Antenna Considerations

license free bands
License-Free Bands

2.4 GHz

315 MHz

420 MHz

900 MHz

5.7 GHz

433 MHz

868 MHz

5.7 GHz

900 MHz

433 MHz

915 MHz

regulatory bodies
Regulatory Bodies

FCC (United States)

IC (Canada)

ETSI (Europe, some APAC)

C-Tick (Australia

Telec (Japan)

Anatel (Brazil)

rates and ranges
Rates and Ranges

Wireless Video Applications

Faster

Video

UWB

Data

Wireless Data Applications

802.11g

802.11a

IrDA

Wi-Fi®

Voice

Peak Data Rate

802.11b

Cellular

2.5G/3G

Bluetooth™

Monitoring

& Control

Data

Transfer

ZigBee™

Slower

Wireless Networking

Closer

Farther

Range

nodes
Nodes

Nodes and Rates

radio modem operation
Radio Modem Operation
  • Modem
    • Modulate / Demodulate
modulation
Modulation

What is modulation?

  • The process by which a parameter (amplitude, frequency or phase of a sinusoidal signal) of a higher frequency carrier wave is altered in accordance with the baseband message signal.
  • Transforms the message signal into a form that is suitable for transmission over the channel.
  • The transmitter uses the baseband message signal to modulate a carrier and transmit it over the channel.
radio modem operation26
Radio Modem Operation

Two types of spread spectrum used in modern Radios

  • FHSS- Frequency Hopping Spread Spectrum
    • Transmitter rapidly hops from one channel to the next in a pseudo-random fashion, avoiding long-term interference.
    • Receiver follows transmitter
    • Some Digi Products use FHSS
      • 24XStream

2400

2480

slide27

XStreamKey Features

  • Price-to-Performance Value
  • High Receiver Sensitivity
  • Low Power Consumption
  • FCC (U.S.A.), IC (Canada),
  • ETSI (Europe) Approved

Best Value OEM RF Modules 2.4GHz

xstream 2 4 ghz best value oem rf modules
XStream (2.4 GHz)Best Value OEM RF Modules

Interface Packages Available

radio modem operation29
Radio Modem Operation

Two types of spread spectrum used in modern Radios

  • DSSS- Direct Sequence Spread Spectrum
    • Each bit is represented by N, shorter segments, called chips.
    • Increases over-the-air rate by a factor of N, widening the spectrum
    • Correlator in receiver examines the chips and maps chips back to bits, while simultaneously spreading undesired signals
    • Processing gain, 10*log(chip_rate/bit_rate)
    • Some Digi productsuse DSSS
      • XBee
      • XBee-Pro
      • All WiFi enabledproducts
digi rf products
Digi RF Products

Modules (Embedded)

Packaged (Boxed)

digirf products
DigiRF Products
  • XBee
  • XStream
  • XTend
  • XPress
  • XCite
  • Digi Mesh
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