Need Help !!! URGENT Questions on Data Communication

[hibiskusi]

Hi folks,

[Bob_Schor]

What have you been taught in your classes about these topics?  What have you learned from your own research?  Have you used the Web, a.k.a. "Ask Google"?  Have you gone to your instructor and asked her (or him) to explain the one (I hope) concept that you do not understand?

Do you think it will help you if we do your homework for you?  Will you give us credit when you hand in your work?

Bob Schor

[Bob_Schor]

That's curious -- shortly after I attempted to answer your question, you edited your original post and removed all of its content!

For those who might be curious why I'm responding to a "blank" question, the OP presented four homework questions and asked us about Bipolar Line and Manchester encoding schemes.

Bob Schor

[hibiskusi]

Hi Bob_Schor,

thank you for your help and assistence. 

I tried to edit some questions and give a reason why i have posted and accidentally i saved them.

Questions are as follwoing.

I had some issues, and was not able to take care continously on this semester and that why i am looking for help.

Please find the questions down and i would appreciate your help.

1. Bipolar line code
The advantage of a bipolar line code is that a bipolar fault (two successive positive or negative pulses, separated by any number of zeros) signals a transmission error to the receiver. Unfortunately, the receiver does not know where this error happened.
The receiver had received the defective sequence. Construct two scenarios (each with a wrongly transmitted signal) that produce the same sequence.

2. The human hearing range is approximately between 20 Hz and 20 kHz. How big must the sampling frequency of music CDs be at least, so that every piece of music can be reconstructed perfectly?

3. Conduct an expression for the baud rate D as a function of a bit rate R for 16QAM using Manchester encoding! Use the maximum number of possible signal changes in Manchester.

4. Monitoring security of multiplexing
Accept an unencrypted radio transmission. Which of the three multiplexing methods (time, frequency and / or code multiplexing) offers the highest monitoring security (0.75P)? Why (0.75P)?

[JÞB]

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@hibiskusi wrote:

Hi Bob_Schor,

thank you for your help and assistence. 

I tried to edit some questions and give a reason why i have posted and accidentally i saved them.

Questions are as follwoing.

I had some issues, and was not able to take care continously on this semester and that why i am looking for help.

Please find the questions down and i would appreciate your help.

1. Bipolar line code
The advantage of a bipolar line code is that a bipolar fault (two successive positive or negative pulses, separated by any number of zeros) signals a transmission error to the receiver. Unfortunately, the receiver does not know where this error happened.
The receiver had received the defective sequence. Construct two scenarios (each with a wrongly transmitted signal) that produce the same sequence.

2. The human hearing range is approximately between 20 Hz and 20 kHz. How big must the sampling frequency of music CDs be at least, so that every piece of music can be reconstructed perfectly?

3. Conduct an expression for the baud rate D as a function of a bit rate R for 16QAM using Manchester encoding! Use the maximum number of possible signal changes in Manchester.

4. Monitoring security of multiplexing
Accept an unencrypted radio transmission. Which of the three multiplexing methods (time, frequency and / or code multiplexing) offers the highest monitoring security (0.75P)? Why (0.75P)?

---

Question two is the only one with an obvious answer.  Probably because it is dangerously phrased.  The answer is "the only way to provide a perfect digital reproduction of sound vibrations is to have an infinite sample rate with infinite bits of resolution."  This is not achievable with the theoretical memory capacity of the universe.  The normal frequency response of the human ear is moot for "perfection of reproduction."  If, on the other hand, the question pertains to a reproduction of sound indiscernable to a human with some percentile of normal human hearing you need to weight the fidelity of the reproduction against sound pressure weighted on a A scale.  Notice we haven't even begun to discuss the medium through which the reproduced sound it to be transmitted, (Vacuum- impossible! vastly different answers entirely for earth normal gasses at 1 atmospere pressure and underwater sound reproduction.)  

More likely your prof wants you to regurgitate some overly simplified formulae from your textbook that he does not fully understand.  Hit the books, or take the course over while you are healthy to learn the material. Failing a class due to health reasons or other distractions and needing to retake the course is not really all that bad.  Faking your way to a degree you did not earn involving material you have not mastered should be a crime.  

If you want the degree do what you need to do to master the concepts needed to answer the questions.  - free advice.

EDIT: I stated incorrectly words to the effect that it is impossible to reproduce a physical vibration through vacuum that is indistinguishabl to the normal human ear. In retrospect, it can be accomplished with any system including one with 0 bits on data.  Nothing sounds exactly like Nothing and Nothing will be neither transmitted nor received in a non-existant medium.

[JÞB]

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@Bob_Schor wrote:

That's curious -- shortly after I attempted to answer your question, you edited your original post and removed all of its content!

For those who might be curious why I'm responding to a "blank" question, the OP presented four homework questions and asked us about Bipolar Line and Manchester encoding schemes.

Bob Schor

---

@ Bob, See here.  thanks for the breadcrumb!  

[hibiskusi]

Hi sir,

By thanking you for your support, since i am in an hard position right now, i would appreciate if you could help me also with three other questions.

Just for your attention, this are not exam questions and i am not going to use them for that purposes. I am just collecting some answers from several question on Data Commucation.

Please if you could helop me, i would appreciate it.

Thank you

[JÞB]

---

@hibiskusi wrote:

Hi sir,

By thanking you for your support, since i am in an hard position right now, i would appreciate if you could help me also with three other questions.

Just for your attention, this are not exam questions and i am not going to use them for that purposes. I am just collecting some answers from several question on Data Commucation.

Please if you could helop me, i would appreciate it.

Thank you

---

I thought I did make it clear.  But I will restate it.  You PAID for the opportunity to be exposed to the concepts needed to answer the questions.  You have not mastered those concepts.  Now you ask us to give you answers demonstrating application of knowledge that you already purchased the access too?  

So, you wasted an opportunity.  OK I feel sorry for you!  Now you want us to waste our time giving you answers that you can't explain because you wasted your time- 

Can you contemplate where that "Just give me an answer I am not paying for with either, time commitment or study" attitude could be offensive?  Take the class again when you have the time to study and master the concepts.  OK, so you fail a course you were unable to devote the required time for.  Why is that URGENT! for us to answer?  It was not URGENT for you to study!

So, I may have just helped you more than a little.  Now, what are your plans to move forward after you fail this attempt at the course you cannot master with the effort you gave it (Reason why are beside the point.  Do you want to master the concepts or not?  If not, why do you care about the answers to questions you should be able to answer?