pre-emphasis and de-emphasis in telecommunication

We are using mobile phones and many digital audio devices and the audio signals are digitized and converted to analog signals that we can hear and enjoy.

A very important technology that is used behind reproducing the best sounds is the concept of pre-emphasis and de-emphasis.

In processing electronic audio signals, pre-emphasis refers to a system process designed to increase (within a frequency band) the magnitude of some (usually higher) frequencies with respect to the magnitude of other (usually lower) frequencies in order to improve the overall signal-to-noise ratio by minimizing the adverse effects of such phenomena asattenuation distortion or saturation of recording media in subsequent parts of the system. That is the mirror of the deemphasis. The whole system is called emphasis. The frequency curve is decided by special time constants. The cutoff frequency can be calculated from that value.

Pre-emphasis is commonly used in telecommunications, digital audio recording, record cutting, in FM broadcasting transmissions, and in displaying the spectrograms of speech signals.

An example of this is the RIAA equalization curve on 33 rpm and 45 rpm vinyl records.

In high speed digital transmission, pre-emphasis is used to improve signal quality at the output of a data transmission. In transmitting signals at high data rates, the transmission medium may introduce distortions, so pre-emphasis is used to distort the transmitted signal to correct for this distortion. When done properly this produces a received signal which more closely resembles the original or desired signal, allowing the use of higher frequencies or producing fewer bit errors.

In telecommunication, de-emphasis is the complement of pre-emphasis, in the antinoise system called emphasis. Emphasis is a system process designed to decrease, (within a band of frequencies), the magnitude of some (usually higher) frequencies with respect to the magnitude of other (usually lower) frequencies in order to improve the overall signal-to-noise ratio by minimizing the adverse effects of such phenomena as attenuation differences or saturation of recording media in subsequent parts of the system.

Special time constants dictate the frequency response curve, from which one can calculate the cutoff frequency.

Pre-emphasis is commonly used in audio digital recording, record cutting and FM radio transmission.

In serial data transmission, de-emphasis has a different meaning, which is to reduce the level of all bits except the first one after a transition. That causes the high frequency content due to the transition to be emphasized compared to the low frequency content which is de-emphasized. This is a form of transmitter equalization; it compensates for losses over the channel which are larger at higher frequencies. Well known serial data standards such as PCI Express, SATA and SAS require transmitted signals to use de-emphasis.

The science behind the design of a nail

What is the science behind the design of a nail? Why does the nail have a flat head, a long straight ahead and a sharp pointed nose or base?

Why is the size of the head of whatever is the size? Why is it of a certain length?

Being a leader means...

Scene:

Boss trying to get the buy in from one of his employees to hire a manager who the employee will report into in the future. He has two candidates Mr.X and Mr.Y. The choice of Boss is different from his employees choice. Boss tries to convince that the choice he has made is the best choice in the long run and requests my feedback.

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My response - that lead to the decision .

Thank you for giving so much regard to my opinion. I will give my thought about hiring. In simple terms "You got to do, what you got to do.". 

I do not want to pick  Mr.X or Mr.Y due to two reasons: 

1. I feel they both are not qualified to do the job.
2. I heard messages that were absolute contrast from Mr.A,Mr.B and Mr.C as compared to Mr.E1,Mr.E2.Mr.E3. 

Managers always face such interesting situations and that is the reason why we are here and what we are here for. I will give you some examples which will make you comfortable announcing your decision. 

1. I hired Ms.E against the will of the team, when the team were not happy and did not have any confidence that a girl can do the job. I trusted my instincts and hired her, she served for 3 years and was a top performer of the team.
2. Mr.H was considered as an average player with good communication skills. I trusted my instincts to promote him. He turned out to be a better manager than his lead and is now handling a team. 

Opportunities make us leaders and the choices we make, makes us who we are: 

1. Owing to disparity in thoughts do not make a decision on Mr.X and Mr.Y and keep the search on.
2. Trust your instincts and your passion to make the company a better place and trust your instincts and your experience and make a decision and go with it. 
3. The choices we make, makes us who we are. You should go ahead and announce your decision. 

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Concluding thoughts:

Leaders are leaders due to the choices they make and living by their decisions and learning from their success and mistakes. Leaders realize, accept and learn from their mistakes and progress.

Perception of an enemy

I was watching the movie Revolver and there was a discussion about an interesting topic. It is about ego and the perception of an enemy. At the end of the movie there were interpretations from thinkers of our age and one of the statement made by them was "all perception of an enemy is a projection of the ego as the enemy".

Now where do we see in real life. I feel one of our world superpower is exactly going down this lane.

The discussion goes as follows, "The brain/mind has an EGO and sees itself as separate from the reality.
It also sees itself as the most important part of the reality. EVERYTHING in our world is built upon the foundations of the energy expressions of EGO.

The single biggest con of the EGO is "I AM YOU". The EGO hides within the last place one would never look.

WITHIN ITSELF

Its disguises it's thoughts as your thoughts, it's feelings as your feelings. You think it's you. Peoples need to protect their own EGOs knows no bounds. They will LIE, CHEAT, STEAL, KILL and do whatever to maintain EGO BOUNDARIES. "

Watch this and read if you are more interested in this.