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Answered 2017-12-10 17:06:18

Basics of LANs and Telecommunications Signal generation and carrier methods used with local area networks deals primarily with basic telecommunications and I.T. theories. Local area networks (or LANs) are inherent to the I.T. (Information Technology) or "computer" world. A good example is a small office with multiple desktop computers linked together through a common server unit. No telecom carrier circuits are required at this level to connect these individual computers to one another inside a particular LAN. "Carrier" circuits come into play when 2 or more LANs are connected. For example, this same small company has 2 different departments in separate offices across town from one another - two different LANs - and they wish to share access to particular data. They would use a telecommunication network (e.g. the phone company) and incorporate various sized carrier circuits to transport their data between the two networks. These circuits are commonly referred to as "broadband carriers". The size of the circuit required would be primarily dependent on the individual network's average level of expected data transfer, with future growth potential factored in as well. These circuits are commonly measured in Mbs (Mega-Bits per second) - - - not to be confused with MB (Megabytes). Without going into too much detail on basic telecom hierarchy . . . the base unit for most applications of interconnecting 2 or more LANs is a DS1/T1 circuit (1.5 Mbs). This is an electrical connection using twisted-pair wire as the primary medium for transport. In simple terms, a T1 is equivalent to 24 individual 64k phone lines (8-bits for overhead on each channel making it the commonly-known 56k worth of payload per channel). If more bandwidth is required for data transfer, the next step is a DS3/T3 carrier circuit (45 Mbs). (A T3 contains twenty-eight T1 channels.) This is an electrical circuit that rides coaxial cable. The next step from there is to jump to fiber optic circuits. The base unit for optical circuits is the OC3 - (Optical Carrier 3). The number relates to the number of T3s, or in optical terms, the number of sts1 payloads that are carried by that single fiber. So, here's a basic example:

Company A wants to share data with Company B - one of its contractors. Company A has a 100Mbs LAN. Company B has a 10Mbs LAN. Company A places an order with the phone company to provide a carrier circuit between the two LANs. This circuit is really nothing more than an empty "pipe" between the two networks. The size of this pipe, as discussed earlier, can be altered to accommodate more or restrict traffic flow. The limitations of the actual data transfer are generally set, however, by the slowest element of a given network. In this example, Company B's LAN only operates at 10Mbs. But, there is the potential for future need/growth. A compromise could be to order a DS3 circuit (45Mbs)to begin with. Granted, the 100Mbs network of Company A would be slowed considerably in any data transfer applications with Company B's LAN, but, from a cost-analysis perspective, that level of bandwidth would still ensure that Company B's transfer rate is used to its max level without incurring the cost of a larger circuit that would be much more bandwidth than is necessary until they upgrade to a similar 100Mbs LAN.

A LAN connects to a carrier circuit through the use of a "router." In simple terms, a router is an interpreter of sorts which converts TCP/IP signal (the language computers use between one another on the LAN) to a Bi-polar electrical signal (for T1/T3 applications) or Sonet - the language of optical carrier circuits. The LAN server typically connects to the router via ethernet cable - and goes out the other side via CAT-5, COAX, or Fiber to a multiplexor that sends it on its merry way across the telecom network to the other location where it then goes through an exactly opposite process of de-mixing down and then converting back from "telecom" language to that of TCP/IP through the use of another router and then off to the server and into the second LAN.

Signal generation is simply what all CPE (customer premis equipment) does. It generates the "live" signal or data that is transported across LANs and between LAns via various carrier methods. Telecom equipment does not "generate" signal. It "re-generates" whatever the customer equipment sends out. It acts like an amplifier of sorts to ensure a stable signal level and prevent signal degradation as the data travels across its network on its way to its eventual destination. T1 and T3 level circuits are very sensitive to fluctuations in signal level and are somewhat limited in the allowable distance between equipment. They are also affected by moisture. Optical carriers are the best medium for data flow. Though they too are sensitive to light-level fluctuations - they are not affected by things such as moisture and other issues inherent to electrical connections. As long as the fiber optic cable is kept clean while connecting ends together and not damaged or bent too drastically, an optical signal can travel several hundred miles before needing to be "regenerated" as opposed to only a few miles on twisted-pair cable or only a few hundred feet in terms of coax cable.

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Signal generation and carrier methods?

figure it ou its ur job


What does FM and AM mean in radio frequencies?

They are methods of transmitting signals (speech, music,data etc) on carrier frequencies. FM is Frequency Modulation where the carrier frequency is modified by the signal frequency. AM is Amplitude Modulation where the carrier amplitude (size) is modified by the signal


What is the difference between carrier signal and modulating signal?

A carrier is a signal does exactly what it says. It carries a signal embedded within it to a radio receiver. The carrier signal is modulated by the music or speech signal to form a modulated carrier wave. Amplitude modulated, that is AM radio, makes the carrier wave voltage vary in sympathy with the audio modulator. In FM radio the carrier is frequency modulated, or varied in frequency by the modulator signal. Both radio types needs a carrier signal to get the modulating signal to the distant radio.


When does Carrier Signal occur?

The carrier signal occurs at the beginning to transmit information.


What are the difference between carrier signal modulating signal modulated signal baseband and passband?

carrier signal- use for the purpose of conveying information. modulating signal- causes variations in some characteristics of carrier signal. modulated signal - carrier signal after altration in its characteristics is called modulated signal. example- if you want to see an object (suppose it is an modulating signal),you need light(light is carrier signal) and when light will reflect on object you will be able to see if (that is modulated signal)


What is amplitude modulation and frequency modulation and phase modulation difference between them?

Amplitude modulation is where a constant carrier is modulated by the signal, so that the envelope of the carrier represents the signal. Frequency modulation is where a constant carrier is modulated by the signal, so that the frequency of the carrier represents the signal. Phase modulation is where a constant carrier is modulated by the signal, so that the phase angle of the carrier represents the carrier.


In which analog-to-analog modulation methods does the peak amplitude of the carrier signal remain unchanged?

Frequency modulation and Phase modulation


Why carrier signal is always in analog signal?

It isn't always. Baseband analog signals have no carrier.


What is modulating signal?

modulating signal is the message to be carried by the carrier signal.


Is carrier signal present at output of double side band suppressed carrier?

No, the carrier signal is not present at the output of double side band suppressed carrier. That is what suppressed carrier means. However, the receiver has enough information to regenerate the carrier if need be. The advantage of suppressed carrier mode is that more power can be deployed to the signal-carrying portion of the modulated carrier.


How receiver detect that which is information signal and which is carrier signal and how it separate both at destination?

carrier is constant frequency information is a change from that constant


Why is the intelligence signal not in the AM envelope?

The intelligence signal is in the AM envelope.In AM modulation, the carrier is amplitude modulated by the signal. This signal appears as the envelope of the carrier. You can demodulate it by following the peaks on each cycle of the carrier. You can either follow the positive peaks or the negative peaks - it does not matter if the original modulation is symmetrical.


What is disadvantage in amplitude modulation with carrier?

You must transmit the redundant carrier with the signal.


What is the difference between SINR and CINR?

SINR - Signal to Interference and Noise Ratio CINR - Carrier to Interference and Noise Ratio difference between those to is difference between carrier and signal carrier is signal who doesn't "carry" any information . it must be modulated( by phase,freq or amplitude) and those changes convey information. carrier is unmodulated signal signal is defined as useful signal which carries information SINR is power of signal to power of interfenence and noise ratio


What is a modulated carrier waves?

A modulated carrier wave is the output of a modulator that includes the information of the signal that is applied to the carrier.When a signal typically a piece of music in the range of say 30Hz to 30KHz is applied to an AM modulator (not sure about FM or PM) with a carrier of say 3MHz the output consists of 4 packetsUpper Sideband (Carrier + Signal) 3.000003MHz to 3.03MhzLower Sideband (Carrier - Signal) .297MHz to .299997MHzCarrier 3MHzSignal 30Hz to 30KHzEither sideband in the case of Single Side Band (SSB) or Both (.297MHz to 3.03Mhz) in the case of Double Side Band (DSB) could be referred to as modulated carrier waves


What cell phone carrier has the weakest signal?

The cell phone carrier that has the weakest signal varies by the market that you live in and even sometimes your location on your street. In the Utah area the carrier with the weakest signal is T-Mobile but that changes if you go to another area.


What are the advantages of modulating a signal before transmission?

without being modulated on a carrier, the signal will not transmitnote: once modulated, in some systems, the carrier can be removed/suppressed and the signal will still transmit OK. but the carrier must first be modulated to transmit.


What converts analog signal information into an analog carrier signal?

Analog Modulation


What is the difference between FM and AM radio waves?

In AM the amplitude of the carrier signal is modulated according to the amplitude of the signal to transmitted but in FM the frequency of the carrier is changed without any change in amplitude of the carrier.


The speed of a t carrier depends on its?

the speed of a T carrier depends on its signal level


How can you block the transmitter signal?

Transmit another signal using the same carrier frequency to interfere with the original signal...also known as "jamming". If you have two signals using the same carrier frequency, and you add a second signal source with the same carrier frequency, and an a stronger amplitude (intensity), but different signal data, then it mixes with the original signal at the receiving end, and the original signal cannot be clearly decoded.


What if the signal is over -modulated?

The usual result is that the carrier is clipped. This results in distortion of the signal and spectral splattering of the carrier, interfering with other carriers.


Why is it necessary to modulate the picture and sound signals before transmission?

Modulation can be thought of as the addition of what we want to transmit to the carrier signal. We say that we modulate (add information or intelligence to) that carrier, so given that, it is fairly easy to see that we are required to modulate the carrier before we transmit that carrier signal. Without any modulation, the carrier is the only thing transmitted. We'd see only that carrier if we intercepted or received the signal.


Why is amplitude of demodulated FM signal much less than modulated signal?

because demodulated FM is an audio signal, which the frequency is much smaller that is why it can be transmitted alone. It need carrier which has large frequency. Modulated signal is an audio signal + carrier that is why the amplitude is higher.


What is the carrier voltage of modulated signal?

The 'carrier' is the signal that's flowing from the antenna into your receiverwhen there's no talk, no music, no sound of any kind on the signal. That'swhen you hear nothing out of the radio, because the radio is built to catchand work with only the changes of the carrier ... the modulation.