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Why transmit frequencies are allocated higher frequencies than that of receive frequencies?
Wiki User
∙ 14y ago
That's not the case at all. A moment's thought will show you why that's impossible ... no 2-way link
could work if that were the rule.
Picture two communications sites talking to each other by radio over a "duplex" link ... meaning that
there's 2-way communication; each terminal can hear the other and talk to the other.
In order for them to communicate with each other, each receiver has to listen to the frequency where
the other end is transmitting.
If one site transmits HI and receives LO, then the opposite site had BETTER transmit LO and receive HI,
otherwise neither site can hear the other one !
It must be that exactly half of all the duplex terminals in the world transmit HI and receive LO,
and exactly the other half must transmit LO and receive HI.
Wiki User
∙ 14y ago
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Why higher frequencies attenuate more than lower frequencies?
Perhaps because the medium more readily absorbs the higher energies of the upper harmonics. This might be related to the stiffness or elasticity of the medium, whatever it happens to be.
Why low frequencies are not used for data transmission in computer networks?
Low frequencies are avoided for data transmission in computer networks to prevent data loss due to attenuation of the signal. Also, low frequencies are incapable of transferring data at the speeds of higher frequencies.
What is the reasone for select Ku band frequency is 1411 G Hz in satellite communications?
Ku band, (Transmit frequency 13.75 to 14.50 GHz, Receive frequency 10.70 to 12.75 GHz dependant on which region of the earth you live in) is used rather than C band (4 to 6 GHz) because the higher frequency allows for broader transmit and receive bandwidths, so more data, computer traffic, movies, etc can be sent. The signal power lost in transmitting from earth to the satellite and back to earth again varies with frequency, but not as a simple linear sloping line increasing with frequency way, it has peaks and troughs. This is because at some frequencies Oxygen and Water absorb much more power and it is difficult to generate enough power to pass a strong signal through the atmosphere, so those frequencies are avoided. Ku band uses a part of the frequency spectrum with a lower atmospheric loss between earth and space, so relatively less microwave power is needed to efficiently transmit to and from the satellite.
Why dont broadcast stations transmit at audio frequencies?
1) If information was transmitted at audio frequencies, then you would actually hear the signal. This would be identical to a speaker playing a song on your stereo. 2) Audio frequencies, in the world of radio frequencies, are long wave-length, low energy signals that can't travel long distances. Again, that's why you can only hear someone's stereo from within eyesight of the system. Human ears can detect from about 3Hz up to around 20KHz (some better than others). 3) True radio frequencies start at in the 100Khz range. This is your most basic radio that uses amplitude modulation (aka AM radio). Many people today that listen to the radio listen to frequency modulated (FM) stations. The difference between AM and FM is beyond the scope of the answer to this question. Being a higher frequency, the signals have more energy and can travel farther distances than audible frequencies. 4) Audible frequencies (sounds the human ear can pick up) can only "transmit" amplitude (loudness or volume) and frequency (high or low pitch). However, higher frequencies, such as those used for radio, can carry much more information than the volume and pitch of a signal. This is a direct result of radio frequencies being harmonics (integer multiples) of audible signals. For instance, if a radio signal has a frequency 20 times higher than the audio signal it is transmitting, then that radio signal can not only carry the audio signal, it can also carry other information, such as information about the broadcast station. A radio signal can "encode" information within the signal allowing more information to be carried than just the audio signal itself.
What is pre-emphasis and de-emphasis in FM?
In FM, the effect of noise is more on higher frequencies when compared with low frequencies. Therefore in order to have high signal-to-noise ratio(low noise), the high frequencies are amplified at the transmitter side and for compensation deemphasis(decreasing the amplitude of those boosted frequencies ) is done at receiver.
What are the advantages of larger radio frequencies over smaller ones?
easier to transmit, higher frequencies radiate better. there is more bandwidth available at higher frequencies. higher frequencies travel in straighter lines so are more directional, this may or may not be an advantage depending on what is needed
Is am frequencies higher then FM frequencies?
no
Why do you need a carrier wave?
In radio transmission, you could theoretically transmit radio signals at audio frequencies. However, because the wavelength of electromagnetism at audio-like frequencies is Huge and the frequency of a radio transmitter dictates the size of the antenna and the power requirement, you would need A Very Big Antenna and a Very Big Power Supply to do this. So, we've learned to transmit at higher "carrier" frequencies, modulating either the amplitude or frequency of the carrier signal with our audio and subtracting the carrier at the receiver end.
Why do we use high frequency waves as carrier waves?
The use of high frequencies for carrier waves in communications permits a higher rate of information transfer than could be accomplished with lower frequencies. The higher frequencies have the potential for higher "data density" or "information density" than lower frequencies.
Which has the higher frequencies ultraviolet or infrared?
Ultraviolet
Are X-rays and Gamma rays higher frequencies than ultraviolet rays?
Yes, X-rays and gamma rays have higher frequencies than ultraviolet rays.
What is ossilloscope?
Basically, is a device which measures the amplitude and frequencies of a sound wave. It is shown on a screen. Closer waves, higher frequencies. Longer waves, lower frequencies.
Does pitch of sound change underwater?
No, the pitch (frequency) does not change, but its speed is much greater* because you are using a totally different medium to transmit the sound, some frequencies can carry farther under water than they do in the air and other frequencies (the high frequencies) can't go as far in water. Sound is a wave the lower the wave the farther it can travel, the higher the wave the shorter distance it can go before it loses it's energy by the dampening effect of the medium. ' ++++ *Mean sound speed in air: 340m/s. In sea-water, about 1500m/s. ' The higher the frequency the greater the damping attenuation, on top of the frequency-independent square-law attenuation by distance anyway, in any medium.
Do X-rays have lower frequencies than infra-red waves?
No. X-rays have much higher frequencies.
Do gamma rays have higher frequencies than radios?
Yes, on the order of 1013 hertz higher.
What waves the shortest wavelength and the highest frequency?
I'll answer your question for a variety of waves. For sound waves, higher pitch sounds have higher frequencies and shorter wavelengths. For water waves, the slowest moving waves have higher frequencies and shorter wavelengths. For seismic waves, S waves have higher frequencies and shorter wavelengths than P waves. For electromagnetic waves, X-rays and gamma rays have higher frequencies and shorter wavelengths than, say, visible light. For quantum mechanical, de Broglie waves, particles with classical analogues of momentum have higher frequencies and shorter wavelengths than individual particles.
Why do higher sound frequencies travel better at night?
Because at night the sun goes down, which is a good thing for frequencies, because the sun is giving of radiation which is disrupting the frequencies. so at night nothing is disrupting the frequencies.
