Electronics Engineering

Modulation is used when information is available in analog form that varies the frequency and/or amplitude of a lower frequency wave, depending on the information it carries. The role of modulation is to place this information onto a carrier frequency that can be transmitted more readily and with least loss of information. There are three fundamental types of modulation - frequency modulation, amplitude modulation and phase modulation. In each of these, a carrier frequency is modulated by a lower frequency, to form a modulated carrier wave. A modulator modulates the carrier frequency, while a demodulator detects the modulation on the carrier wave and recovers the original lower frequency waveform at the destination. For many years the modulated carrier wave was converted to a radio signal. Now it is often an electrical signal which is sent down a teleohone line; the information is usually a set of pulses going between computers. When computers are connected to each other in a two-way conversation, the MOdulator and DEModulator are combined into a single device called a MODEM.

Variable DC power supply is:

Variable - you can adjust it

DC - direct current, electrons (electricity) flows in only one direction

power supply - power supply

Together, it's an adjustable one-way power supply

Hope you find this useful...

beams

FSK is not always used for high-speed data communications, since it is far less efficient in both power and bandwidth than most other modulation modes. In addition to its simplicity, however, FSK has the advantage that encoded signals will pass through AC-coupled links, including most equipment originally designed to carry music or speech.

Common Mode gain is the response of a circuit where the input changes relative to some common point, such as ground. A single transistor amplifier is an example. An op-amp can also be an example, if one input is grounded.

Differential Mode gain is the response of a circuit where the input is measured across two pins, and the difference between those two pins controls the output, rather than the common mode value of those pins relative to ground. An op-amp in balanced or bridge mode is an example.

One way to verify/understand this is to take a properly designed op-amp, connect the two inputs together, and drive them together relative to ground. A properly balanced system will exhibit little or no response on the output. Note: This is also true for AC, so a typical test includes both DC and AC response. In the AC test, imbalance often results from unequal capacitance, whereas DC imbalance results from unequal resistance.

To detect, track, and sometimes identify objects via the emission of radio waves.

Speed radar (like those used by police) can detect nearby objects and calculate their speed.

Weather radar can detect the location of clouds and rain.

Air traffic radar can detect and track unidentified flying objects. With the help a monopulse secondary surveillance radar, the radar system can identify the individual planes.

Higher technology radars can detect and identify distant small objects with great precision.

An offset is something which acts as a counterbalance, or a form of countertrade agreement where the seller agrees to purchase products of a certain value within a chosen time.

entity is a thing in the real world with an independent existance. and entity set is collection or set all entities of a particular entity type at any point of time.

take an example:

a company have many employees ,and these employees are defined as entities(e1,e2,e3....) and all these entities having same attributes are defined under ENTITY TYPE employee.and set{e1,e2,.....} is called entity set.

we can also understand this by an anology .

entity type is like fruit which is a class .we havn't seen any "fruit"yet though we have seen instance of fruit like "apple ,banana,mango etc.hence..

fruit=entity type=EMPLOYEE

apple=entity=e1 or e2 or e3

enity set= bucket of apple,banana ,mango etc={e1,e2......}

as voltage amplifier
current follower





i am yoges

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They also buy and sell stuff

They arre in Leeds West Yorkshire

The basic principle of generator excitation is that once the gasket of tie generator is being checked, the generator excits as if the block is not inserted. By egbebu emmanuel

No

Less expensive - Several miles of optical cable can be made cheaper than equivalent lengths of copper wire.

Higher carrying capacity - Because optical fibres are thinner than copper wires, more fibres can be bundled into a given-diameter cable than copper wires. This allows more phone lines to go over the same cable or more channels to come through the cable into your cable TV box.

Less signal degradation - The loss of signal in optical fibre is less than in copper wire.

Light signals - Unlike electrical signals in copper wires, light signals from one fibre do not interfere with those of other fibres in the same cable. This means clearer phone conversations or TV reception.

Digital signals - Optical fibres are ideally suited for carrying digital information, which is especially useful in computer networks.

Non-flammable - Because no electricity is passed through optical fibres, there is no fire hazard.

Lightweight and thin - An optical cable weighs less than a comparable copper wire cable. Optical fibres can be drawn to smaller diameters than copper wire. Fibre-optic cables take up less space in the ground.

To get all the audio voltage from a source to a target without loss you need voltage bridging, that is a relative low output impedance to a higher input impedance. Usualy the input impedance is at least ten times higher then the output impedance.
An input impedance is called also a load impedance or an external impedance.
An output impedance is called also a source impedance or an internal impedance.

A: I hope you mean replace. The answer is yes provided that the voltage rating is the same or more then the original.

A diode is unidirectional because of the diode only conduct in forwardbias .As you know the diode have two terminal cathode and anode . and when the positive terminal of battery connected to the p-side and other terminal connected to the other terminal of diode then diode is called forward biased . and when it connection is just opposite then it become in reverse biased .

so we can finally say that the diode is unidirectional

The first digital media in the world was the digital watch. This item gained strongly on the market in those years and is still used by many. Casio is probably the most famous company that produces digital watches.

Some examples of applications of phase modulators are: * A phase modulator within a laser resonator of a single-frequency laser can be used for wavelength tuning, or for active mode locking (FM mode locking) of a laser. * A phase modulation of a beam with moderate modulation strength is often used in laser frequency stabilization schemes, e.g. with the Pound-Drever-Hall method. * Various kinds of interferometers and setups for spectroscopic measurements require phase modulators, often with a periodic drive signal. * Some metrology applications require frequency combs, generated by sending a single-frequency beam into a phase modulator. In that case, the phase modulation often needs to be strong in order to obtain a large number of optical sidebands. * In data transmitters of optical fiber communication systems, phase modulators can be used for encoding the transmitted information. An example is the method of phase shift keying. Source: http://www.rp-photonics.com/phase_modulators.html

if the load is capacitance then reactive power is injected in the circuit, as we know that reactive power is directly proportional to the voltage, if there is increase in reactive power automatically voltage at load end of the tranformer is increases

A dc generator is a machine which works on the principle of electro magnetic induction $it converts the mechanical energy into electrical energy.

no,we cant use transistor by combination of two diodes because we will come across a condition called current hogging.it means large amount of current flows through the device,diode can just rectify the signal but not amplifies it.

Transistors however, can be used as diodes.