Have a few questions that i need clarification on....

[MBH_14]

1. A 5-second video with 30 frames per second, each frame with a resolution of 480x720 pixels in three colors, each color taking 4 bits has

a. 41472000 bits
b. 31104000 bits
c. 622080000 bits
d. 10368000 bits
e. 4147200 bits

for this i got C, 622080000.

2. What is the streaming rate for the video of problem 1?

a. 1382400 bits/s.
b. 124416000 bits/s
c. 41472000 bits/s
d. 4147200 bits/s
e. 622080000 bits/s

For this i am not sure how to do, can someone show me?

3. How long does it take to send a 1Kbyte file over a 1Mbytes/s channel that is 100 km long? Assume speed of light in that channel is 2x10^8 m/s.

a. 1 ms
b. 0.5 ms
c. 1.5 ms
d. 2 ms
e. 2.5 ms

For this i got C, 1.5 ms.

4. How long does it take for the first bit to arrive from the transmitter to the receiver over a 10 Mbps channel of 1000 km. Assume speed of light is 2x10^8 m/s.

a. 50 ms
b. 5 ms
c. 0.5 ms
d. 500 ms
e. Insufficient information to answer

For this i got B, 5 ms.

Alright, so all i need is clarification that i did numbers 1, 3, and 4 correctly, and if someone could show me how to do #2, that would be great. I would appreciate any and all help and really am thankful for the help you guys give me! Thanks a lot!

Michael

 

[tkhunny]

1) Good.
2) You have the rate for five (5) seconds. It is only a brief division problem to convert to a rate per one (1) second.

 

[MBH_14]

thanks, #2 was just so easy that it tricked me into thinking there was more that had to be done, lol. Any idea if i was correct on 3 and 4? Thanks!

 

[wjm11]

3. How long does it take to send a 1Kbyte file over a 1Mbytes/s channel that is 100 km long? Assume speed of light in that channel is 2x10^8 m/s.

a. 1 ms
b. 0.5 ms
c. 1.5 ms
d. 2 ms
e. 2.5 ms

For this i got C, 1.5 ms.

4. How long does it take for the first bit to arrive from the transmitter to the receiver over a 10 Mbps channel of 1000 km. Assume speed of light is 2x10^8 m/s.

a. 50 ms
b. 5 ms
c. 0.5 ms
d. 500 ms
e. Insufficient information to answer

For this i got B, 5 ms.

Michael,

I think 3 is a bit of a trick question; the speed of light info is superfluous in this case. The problem is really just the first part of the question: How long does it take to send a 1Kbyte file over a 1Mbytes/s channel? To find the time require, divide the size of the file by the rate, 1 kb/ (1 MB/s) = 1 ms.

For 4, divide the distance by the rate (in this case, the rate is the speed of light). Be careful of your units.

BTW, it would be best to show your work so that the tutors here can see your logic and spot anywhere you might have gone wrong.

Hope this helps.