Quantcast SINGLE-SIDEBAND TRANSMITTER

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
2-7 SINGLE-SIDEBAND TRANSMITTER You should remember the properties of modulation envelopes from your study of NEETS, Module 12, Modulation Principles. A carrier that has been modulated by voice or music is accompanied by two identical sidebands, each carrying the same intelligence. In amplitude-modulated (AM) transmitters, the carrier and both sidebands are transmitted. In a single-sideband transmitter (ssb), only one of the sidebands, the upper or the lower, is transmitted while the remaining sideband and the carrier are suppressed. SUPPRESSION is the elimination of the undesired portions of the signal. Figure 2-7 is the block diagram of a single-sideband transmitter. You can see the audio amplifier increases the amplitude of the incoming signal to a level adequate to operate the ssb generator. Usually the audio amplifier is just a voltage amplifier. Figure 2-7.—Ssb transmitter block diagram. The ssb generator (modulator) combines its audio input and its carrier input to produce the two sidebands. The two sidebands are then fed to a filter that selects the desired sideband and suppresses the other one. By eliminating the carrier and one of the sidebands, intelligence is transmitted at a savings in power and frequency bandwidth. In most cases ssb generators operate at very low frequencies when compared with the normally transmitted frequencies. For that reason, we must convert (or translate) the filter output to the desired frequency. This is the purpose of the mixer stage. A second output is obtained from the frequency generator and fed to a frequency multiplier to obtain a higher carrier frequency for the mixer stage. The output from the mixer is fed to a linear power amplifier to build up the level of the signal for transmission. Suppressed Carrier In ssb the carrier is suppressed (or eliminated) at the transmitter, and the sideband frequencies produced by the carrier are reduced to a minimum. You will probably find this reduction (or elimination) is the most difficult aspect in the understanding of ssb. In a single-sideband suppressed carrier, no carrier is present in the transmitted signal. It is eliminated after modulation is accomplished and is reinserted at


Electrical News
Europe Leads in Chip Market Growth
In July, Europe showed the strongest year-on-year growth of all...
eetimes.com
Trillion Sensors Not Likely
The trillion-sensor world is not going to happen anytime soon....
eetimes.com
IoE: Internet of Earthquakes?
Data scientists at Jawbone recently published findings on the quake's...
eetimes.com
Apple iPhone 6: Mobile Payments Pioneer?
Apple's latest iPhone could help bring mobile payments to the...
eetimes.com
MIPS Moves Multicore Battle to Clustering
Imagination Technologies launches its I-class I6400 MIPS 64-bit processor with...
eetimes.com
How to Fly Without Catching the Dreaded Lurgy?
On returning from his trip to Brazil, Max was diagnosed...
eetimes.com
Anatomy of an ARM Server Chip
Four out of the top five server IC companies prefer...
eetimes.com
IoT Gives Old Technology New Life
Cypress Semiconductor sees a great deal of potential for SONOS...
eetimes.com
Andes Ready to Rumble in CPU War
With ARM reigning as king of the CPU IP market...
eetimes.com
D-PHY, M-PHY & C-PHY? First Look at Testing MIPI's Latest PHY
One of the significant advantages of MIPI Alliance standards is...
eetimes.com
Homeless in Silicon Valley
Over Labor Day, I thought about the situation for the...
eetimes.com
Wireless Net Takes the Next Train
The first products are about to adopt the new 802.15.4p...
eetimes.com
EEVblog #659 – Medical Plugpack Teardown
What’s inside an IEC60601-1 medical class 5V mains DC-DC plugpack?...
eevblog.com
Ethernet Links Go Green
Everything that uses energy uses too much if it. Energy...
eetimes.com
Android Wear: Where Are the Wares
Here are examples of some of the watches that use...
eetimes.com
Intel Wearables Contest Goes New Age
Emotional prosthetics, modular smartbands and sixth sense necklaces make up...
eetimes.com
EEVblog #658 – Mailbag
Mailbag Monday. Dave opens his mail Spoilers: Keithley 177 Multimeter...
eevblog.com
EEVblog #657 – Maker Faire 2014 Interviews
Some interviews from the 2014 Sydney Mini Maker Faire at...
eevblog.com
The Internet of Things Versus Slumlords
Smart thermostats are not only for the well-to-do. One group...
eetimes.com
IBM Watson Speeds Drug Research
IBM Watson moves from supplying known answers to tough questions...
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 +