Electronics Engineering

In Optical Fiber Communication system 1300-1550 nm range wavelengths are used.. Reason for tis s "In this range only we can acheive low attenuation with zero dispersion"

telkom system, CD laser disks, digital audio recording, digitized video special effects, voice mail, digital video.

It is also widely used in Radio Control Units.

Radio transmitter and receiver for remote controlled cars, planes, boats etc.

Often abbreviated with PCM in these.

A pulse code modulated radiosignal is more resistant to interference than a normal "old-fashioned" signal.

a powerful feature of 8051 I/O ports is their capability to access individual bits of the port without altering the rest of the bits in that port. of the four 8051 ports we can access either the entire 8 bits or any single bit without altering the rest

The main reason of selecting a lower frequency for up-link channel in GSM is because of free space path loss. The more is the frequency the more is the loss.

As mobile phones, being a battery driven device, have limitation in terms of power we should always look for lower path loss. Whereas BTS antennas can transmit the signal (in down-link channel) with a comparatively high power, which will compensate the path loss.

And that is why it is chosen to have lower frequency for up-link and higher frequency for down-link in GSM standards. The same theory applies in almost all type of radio communication.

NOTE: Frequency and power are independent of each other. For example you can control the transmission power of BTS antenna, which still transmits in the same frequency.

That's because the path of the short circuit provides a much lower resistance than the actual path and which the current will choose to flow through the path with a lower resistance rather than the path connected to a bulb,which explains that why the bulb won't light up.

You take the wire(s) that are in the circuit and place it on on a compass. Hold the compass still and the needle in the compass will move. However far that the needle is turned will detrmine how much resistance is in the circuit. (You know you have done this correctly if the needle in the compass spins counter clockwise.) Hope this helps you out :)

the relay used to protect the generator/motor from overload currents. And to protect insulation of the stator windings.

The input to the max232 ic will be of Transistor Transistor Logic (TTL) and its voltage range will be of 5 volt. The output of the max 232 ic will be of Recomended Standard 232 Logic (RS232 logic) and its voltage range will be of 12 volt. The max 232 ic which is operating on 5 volt supply has to step up the 5 volt input to 12 volt. Hence a capacitor is used for pumping the voltage and called as pumping capacitor.

There are many types of transmitters. Thesimplest is the Amplitude Modulated (AM) transmitter. This is an oscillator that cycles at a predetermined frequency. This oscillator puts out a level of energy that is varied by the sounds that you desire to transmit. This variance is done from 100% of the signal to 0%. The output then is two frequencies combined one at the stations frequency and one at the frequency of the sound transmitted. The receiver throws away the transmission frequency and amplifies the frequency of the sound.

Bottom line is you only hear the sound stuck into the transmitter.

F.M. is the same as AM but instead of varying power, we vary the frequency with the desire sounds we want to hear. The receiver sees that variance and converts that to sound.

Phase shift, DSB, SSB and the others are merely more complex variances to these basics.

An independent source is a source that produce constant currents and voltage. Dependent sources are voltage sources that depend on a voltage somewhere else in the network.

The current in each.

computers are called silico sepians

The function of the bullet train is to move large amounts of people quickly from one point to another. The bullet train improves the efficiency of the transportation system allowing it to serve higher numbers of people.

They are not the same. Its like asking how many feet equals 10 lbs. Volts are a unit of electrical potential. In hydraulic terms, comparable to water pressure. Joules are energy or "work done". In hydraulic terms a water mill can do work (grind corn say). The work done or energy consumed can be measure in joules.

Let A,B,C are inputs and Y is the output.

A B C Y

0 0 0 0

0 0 1 1

0 1 0 1

0 1 1 1

1 0 0 1

1 0 1 1

1 1 0 1

1 1 1 1

Mind it that Y=A+B+C is a logical operation in our case i.e. OR operation. It's not an arithmetic operation (i.e. not a sum operation).

Where a single diode is used as a rectifier you get halfwave rectification when the sinus wave is going positive the diode will conduct but in the negative half of the cycle it will block the current flow so the result wave form will be only the positive half that will be available for half the period of the cycle the other half will be 0 Volt

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.