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What is the difference between frequency division multiplexing and freq division multiple access?
Wiki User
∙ 14y ago
The basic difference between fdm and fdma is that fdm is used in wired system where as fdma is used in wireless communication.
Wiki User
∙ 14y ago
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Why PLL better than VCO?
A PLL is different than a VCO. Each has its own use. Actually a PLL (Phase Locked Loop) contains a VCO (Voltage controlled oscillator). A VCO is an oscillator whose frequency is related to an input voltage. You can use it when you need a varying frequency that is controlled by a varying voltage. But it is not great at outputting a consistant exact voltage because it is very sensitive to its environment (e.g. temperature). A PLL will "lock" its output frequency to some input frequency. So it can oscillate at a frequency that is controlled by an input oscillator. Not too useful if the output frequency is the same as the input. But the output frequency can be divided before it is compared to the input. This allows the output frequency to be higher (some multiple of) the input frequency. Once a PLL is "locked on" to an input frequency it can be very stable.
Explain how a single fiber optic cable can handle two way communication both half and full duplex?
A single fiber optic cable can facilitate two-way communication through a method called wavelength division multiplexing (WDM). WDM enables the transmission of multiple signals (or wavelengths of light) simultaneously over the same fiber optic cable, allowing for both half-duplex and full-duplex communication. Here's a brief explanation of how this works: Wavelength Division Multiplexing (WDM): Wavelength division multiplexing involves using different wavelengths of light to carry multiple signals over the same fiber optic cable. Two common types of WDM are: Coarse Wavelength Division Multiplexing (CWDM): Uses fewer wavelengths spread over a wider range. Dense Wavelength Division Multiplexing (DWDM): Utilizes more closely spaced wavelengths, allowing for higher data capacity. Half-Duplex Communication: In half-duplex communication, data can be transmitted in both directions, but not simultaneously. WDM can be configured to use different wavelengths for upstream and downstream communication. For example, one wavelength can be assigned for transmitting data from the source to the destination (upstream), and another wavelength for transmitting data from the destination back to the source (downstream). Full-Duplex Communication: In full-duplex communication, data can be transmitted simultaneously in both directions. This can be achieved by using separate wavelengths for upstream and downstream, allowing for independent transmission paths. For instance, one wavelength can be dedicated to upstream data flow, while another wavelength is used for downstream data flow. Bidirectional Communication: By utilizing different wavelengths for different directions, the fiber optic cable effectively supports bidirectional communication. Each communicating party can use its assigned wavelength to transmit and receive data independently. In summary, Wavelength Division Multiplexing (WDM) allows a single fiber optic cable to handle two-way communication, whether it's half-duplex or full-duplex, by employing different wavelengths for different communication paths. This enables simultaneous data transmission in both directions over the same fiber optic link.
What is a harmonic mean?
When applied to electrical waveforms, a 'harmonic' is a multiple of the fundamental frequency.
How do op-amp amplify in signal conditioning?
If an inline capacitor is inserted in the feedback from the output to the input of an op-amp it will act as a frequency filter and only boost audio frequencies within the resonant frequency range of the capacitor. If you gang multiple op-amps in a wein bridge arrangement you get an analogue audio filter capable of shelf boost or cut.
What is the impedance of a full wave dipole?
Typically, the desired frequency of operation is known, and the purpose of thecalculation is to identify the best size for the dipole antenna. The most oftenused formula to find that length isLength = 468/frequency, MHz feet, or 142.6/frequency, MHz meters.That gets you close, but some tweaking and trimming is usually required afterconstruction, because some of the characteristics of the installation, such asthe antenna's height above ground and method of supporting its ends, affectthe antenna's properties.The wavelength corresponding to that frequency isWavelength = 300/frequency, MHz meters, or 984/frequency, MHz feet.The way your question is written, it appears that you already have the antenna, andnow you want to know the frequency at which it will operate best. I must tell youhow peculiar this sounds to anybody in the radio business. But I'm here to answerquestions if they make sense, not to judge how impractical or useless they mayactually turn out to be. So here goes:For the first time ever, you've just noticed a horizontal wire hanging between twotrees in your back yard. Rather than simply tearing it down, you're curious to knowthe frequency/wavelength at which it could most efficiently transmit/receive whenoperated as a half-wave dipole. So you measure its length somehow, and call thelength ' L ' .-- If you measured ' L ' in feet, then the best frequency to try first is 468/L MHz.The corresponding wavelength is 2L feet, or 0.6096L meters.-- If you measured ' L ' in meters, then the best frequency to try first is 142.6/L MHz.The corresponding wavelength is 6.562L feet, or 2L meters.
What is the definition of the word 'multiplexing'?
Multiplexing is the process of combining multiple signals over one media line. There are several types of multiplexing: frequency division, time division, and wavelength division.
What are three common examples of frequency division multiplexing?
AM radio broadcasting uses frequency division multiplexing to allocate different frequencies to different radio stations. Cable television systems use frequency division multiplexing to transmit multiple channels simultaneously over a single cable. Cell phone networks use frequency division multiplexing to separate different users' calls on the same frequency band.
What modulation technique used in mobile phones?
Currently the mobiles use GSM(Geo Synchronous Mobiles ) and CDMA(Code Division Multiple Accesss) techniques. GSM inturn uses TDMA(Time Division Multiplexing) or FDMA(Frequency Division Multiplexing) or sometimes both to fit in the required criteria.
How the operation of tdm and fdm?
Time Division Multiplexing and Frequency Division Multiplexing. Allows multiple data channels across a single medium by separating the data streams onto different frequencies (FDM), or by sending one stream, waiting, then sending the other stream (TDM).
What Is a technology used with fiber optic cable which enables one fiber optic connection to carry multiple light singals simultaneously?
WDM (wavelength division multiplexing)
What is multiplexing why is multiplexing needed in electronics communication?
multiplexing refeers to the transmission of different signals in the same channel simultaneously. There are many forms of multiplexing that can be used, including frequency division multiplexing(FDM) where individual signals are transmitted over adjacent , non overlapping frequency bands. they are transmitted in parallel and simultaneously in time. In time division multiplexing(TDM) each signal is allowd to use the whole bandwidth for a certain period of time. Multiplexing is needed so that the available channel can be used efficiently and also to save costs. There is too much to know about multiplexing, here is just a short overview. One thing that one has to know is multiple access.
What has the author Faouzi Bader written?
Faouzi Bader has written: 'Advances on processing for multiple carrier schemes' -- subject(s): Orthogonal frequency division multiplexing, Multiple access protocols (Computer network protocols)
Difference between multiplexing and multiple access techniques?
Multiplexing and multiple accessModern telephone networks allow bandwidths in their channels that are much larger than those is needed for a digitalized telephone channel. Basically, a number of channels share a common transmission medium with the aim of reducing costs and complexity in the network. Multiplexing is defined as the process by which several signals from different channels share a channel with greater capacity. When the sharing is carried out with respect to a remote resource, such as a satellite, this is referred to as multiple access rather than multiplexing. There are various ways of performing this sharing:# FDM/FDMA (Frequency Division Multiplexing/Frequency Division Multiple Access): Assigns a portion of the total bandwidth to each of the channels. # TDM/TDMA (Time Division Multiplexing/Time Division Multiple Access): Assigns all of the transport capacity sequentially to each of the channels. # CDMA (Code Division Multiplexing Access): In certain circumstances it is possible to transmit multiple signals in the same frequency and at the same time, with the receiver being responsible for separating them. This technique has been used for years in military technology, and is based on extending the spectrum of the signal and reducing the transmission power. # PDMA (Polarization Division Multiple Access): Given that polarization can be maintained, the polarization direction can be used as a multiple access technique, although when there are many obstacles noise can make it unsuitable, which is why it is not usually used in indoor installations. Outside, however, it is widely used to increase transmission rates in installations that use microwaves. # SDMA (Space Division Multiple Access): With directional aerials, the same frequency can be re-used provided the alignment of the aerials is correctly adjusted. There is a great deal of interference but this system lets frequencies obtain a high degree of reusability.
Definition of broadband?
Broadband refers to telecommunication that provides multiple channels of data over a single communications medium, typically using some form of frequency or wave division multiplexing.
What has the author Andrea Borella written?
Andrea Borella has written: 'Wavelength division multiple access optical networks' -- subject(s): Multiplexing, Wave length, Congresses, Wavelength division multiplexing, Light, Optical communications
What wireless local loop technology uses time division multiple access?
GSM - Global System for Mobile Communications (2G) uses TDMA - Time Division Multiple Access Multiplexing.
Whats the difference between baseband and broadband?
In Baseband, data is sent as digital signals through the media as a single channel that uses the entire bandwidth of the media. Baseband communication is bi-directional, which means that the same channel can be used to send and receive signals. In Baseband no frequency-division multiplexing is not possible. (Multiplexing (short muxing) is a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium.)Broadband sends information in the form of an analog signal. Each transmission is assigned to a portion of the bandwidth, hence multiple transmissions are possible at the same time. Broadband communication is unidirectional, so in order to send and receive, two pathways are needed. This can be accomplished either by assigning a frequency for sending and assigning a frequency for receiving along the same cable or by using two cables, one for sending and one for receiving. In broadband frequency-division multiplexing is possible
