MadeEasy Test Series 2017: Computer Networks - Serial Communication

Question

In synchronous transmission, 5 eight bit characters are included in 30 eight bit information characters. If bit rate of sender is 4200 bits/sec, what is the bit rate of receiver (in bits per sec)?

Comments

I think 3500bit/sec .

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how the reciever rate will be 3500bits/sec please explain?

 

"5 eight bit characters are included in 30 eight bit information characters."

WHAT DOES IT MEAN

a) do we add explicitly 40 bits with the 240 bits(i.e. 240+40(sync bits)==280)

b)or do we have a total of 240 bits which in themselves containing 40 syn bits(i.e. 240=sync bits+actual data bits  )

3500 is the answer for the second assumption i guess.please clarify

Answer 1

In synchronous transmission

• Sync characters are added before and after of complete character stream.
• transmission time and receiving time should be same ie, synchronized.

Transmission time= data size / transmission rate =30*8 /4200 = 240/4200 sec

But extra 5 eight bit sync characters also will be added for synchronization, and receiver has to receive whole message within same time.

Receiver bit rate = (data size+ sync character size)/receiving time

= (30*8+5*8)/(240/4200)    //****bcz receiving time= transmission time

= 4900 bits per sec

Comments

If sender is sending @4200 then how could receiver receiver receive at 4900 bps?

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@rahul

your point is clear. This question is little ambiguous.

but what do you mean (senders transmission time = receiver's transmission time).

I think they are expecting an answer like how shiva interpreted.

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Yes seems to be ambiguous question