Quantcast TRANSMISSION LOSSES

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
2-27 Figure 2-21.—Multipath transmission. Multipath fading may be minimized by practices called SPACE DIVERSITY and FREQUENCY DIVERSITY. In space diversity, two or more receiving antennas are spaced some distance apart. Fading does not occur simultaneously at both antennas; therefore, enough output is almost always available from one of the antennas to provide a useful signal. In frequency diversity, two transmitters and two receivers are used, each pair tuned to a different frequency, with the same information being transmitted simultaneously over both frequencies. One of the two receivers will almost always provide a useful signal. Selective Fading Fading resulting from multipath propagation is variable with frequency since each frequency arrives at the receiving point via a different radio path. When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. This variation is called SELECTIVE FADING. When selective fading occurs, all frequencies of the transmitted signal do not retain their original phases and relative amplitudes. This fading causes severe distortion of the signal and limits the total signal transmitted. Q23.   What is the skip zone of a radio wave? Q24.   Where does the greatest amount of ionospheric absorption occur in the ionosphere? Q25.   What is meant by the term "multipath"? Q26.   When a wide band of frequencies is transmitted simultaneously, each frequency will vary in the amount of fading. What is this variable fading called? TRANSMISSION LOSSES All radio waves propagated over ionospheric paths undergo energy losses before arriving at the receiving site. As we discussed earlier, absorption in the ionosphere and lower atmospheric levels account for a large part of these energy losses. There are two other types of losses that also significantly affect the ionospheric propagation of radio waves. These losses are known as ground reflection loss and free space loss. The combined effects of absorption, ground reflection loss, and free space loss account for most of the energy losses of radio transmissions propagated by the ionosphere.


Electrical News
Friday Quiz: Bipolar Transistors
Remember basic transistor physics? Let's see if you really do....
eetimes.com
9 Top Tech from Electronica 2014
After 50 years, Europe's bellwether conference Electronica shows the state...
eetimes.com
Micron Expands IoT & Auto Memory Products
Micron expanded its offerings for embedded applications and the connected...
eetimes.com
Moore's Law Competitor Wins $150K Elevator Pitch Prize
Quilt packaging wins $150,000 prize for best elevator pitch explaining...
eetimes.com
Nexus 6 Vs. iPhone 6 Plus: Phablet Deathmatch
There's never been a better time to buy a big-screened...
eetimes.com
Europe vs. Google
Google may not give much thanks for the gift Europe...
eetimes.com
Stephen Hawking: How He Speaks & Spells
The technology that helped resurrect the life of Stephen Hawking...
eetimes.com
Sony's 3-Year Plan: Treading Water or Just Sinking?
Sony's three-year outlook for its mobile business "isn't aiming for...
eetimes.com
HMC Spec Update Signals Healthy Adoption
The release of the Hybrid Memory Cube specification 2.0, along...
eetimes.com
Power Week: Si-Based Power Discretes to Continue to Dominate Over Next Decade
Discrete power electronics are predicted to become a $23 billion...
eetimes.com
Book Review: Deadly Odds by Allen Wyler
This is a great read that will have you on...
eetimes.com
Supercapacitors: A New Hero in the Spotlight
Today's supercapacitors are being used to replace rechargeable batteries in...
eetimes.com
EEVblog #687 – EFTPOS PIN Pad Terminal Teardown
What’s inside a smart card pinpad EFTPOS terminal? Dave looks...
eevblog.com
Your Part in the Recovery
Engineers and innovators are central to the slow but ongoing...
eetimes.com
Motor Controllers Offer Improved Noise Immunity
Operating at 5V gives these digital signal controllers enhanced noise...
eetimes.com
NXP to Pick Up Its Missing IoT Link - Bluetooth Low Energy
In pursuit of the Internet of Things market, NXP Semiconductors...
eetimes.com
USB Oscilloscopes Get Beta Drivers for Open-Source Hardware
Pico Technology has released beta versions of drivers for BeagleBoneBlack...
eetimes.com
It's Alive! The 3D Printing of Living Tissues
Within a generation, we likely will not just hear of...
eetimes.com
Curiosity Killed the Cat (Just Call Me Mr. Curiosity)
Max desperately needs a cat deterrent, but how should this...
eetimes.com
Memory Design Articles: Diagnostics, Datacenters & Failures
Here's a roundup of recent design articles that are relevant...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +