1)why faithful transmission require analog to be converted into digital?

Question

2)what exactly means quality factor?

3)do skin effect only occurs at high frequency and not at low frequency?

4)how free space and wireless communication takes place?

5)what decides signal strength?

6)tell me something about coaxial cable?

7)how bandwidth is calculated by knowing the frequency of the signal?

8)how measuring devices measure rms values &why?

9)why dish t.v's or antennas are parabolic in shape?

Answer 1

1) Not true. In fact, digitization of a signal necessarily introduces some degree of distortion. It's just that we design the system to keep that distortion to an inaudible level.

The problem with analog is that analog signals are much more subject to the introduction of noise at later points. Once a signal has been digitized, it will not be further degraded as long as the digital signal is properly received.

One advantage of analog, though, is that under poor conditions, you might have a noisy signal, but it may still be useable. If a digital signal gets corrupted, you lose everything.

2) Quality factor can mean a lot of things, but I'm guessing that you're talking about the Q of a circuit. Put in layman's terms, Q is a measure of how sharp of a band of frequencies a circuit will respond to. If a circuit responds to a wide range of frequencies, it has a low Q; if it responds to a very narrow range of frequencies, it has a high Q.

High Q is not necessarily better than low Q. It depends on the purpose of the circuit.

3) Skin effect is present at all frequencies, but is negligible at low frequencies.

4) People write major books about that subject. About the best I can say in this short space is that electromagnetic energy imparted to the environment in one place can be detected in another place. After that, it's just about improving the sensitivity of the detection.

5) The strength of the transmitted signal and the medium through which it propagates

6) Coaxial cable is a cable built with one insulated wire in the center. Outside of that is another conductor, usually made of wire braid or metallic tape, that shares the same center axis as the center wire, hence the name coaxial. The outer conductor also usually has an insulating covering. The outer conductor is usually grounded.

7) I'm going to leave this one for someone else since you don't say whether it's analog or digital

8) I don't know _how_ they do it and I don't have time to look it up right now. They do it because the RMS value is representative of the energy (or more loosely, the power) available.

9) Because a parabola focuses energy to a single point. Place your receiver at the focus point and the parabola will reflect more signal to the receiver than it could get from most other methods.