Please exaplan how to do and formula to calculate? Figure below shows a multiple

Question

Please exaplan how to do and formula to calculate?

Figure below shows a multiplexer. If the slot is only 10 bit long (3 bit taken from each input plus one framing bit) What is the output bit stream? What is the frame rate? What is the output bit rate? What is the duration of each bit in the output line? We need to use synchronous TDM and combine 20 digital source, each of 100 kbps. Each output slot carries 2 bits from each source but one extra but is added to each frame for synchronization. What is the size of an output frame in bits? What is the output frame rate? What is the duration of an output frame? What is the output data rate? What is the efficiency of the system? (ratio of data bits to total bits) Assume that 5 source, 2 with a bit rate 20kbps and three with a bit rate of 40 kpbs are combined using multiple slot TDM with no synchronizing bits. What is the size of a frame in bits? What is the frame rate? What is the duration of a frame? What is the data rate?

Explanation / Answer

In syncronous transmission in TDM multiplexer allocates exactly the same time slot to each device at all times, whether or not a device has anything to transmit, So

i. Output = [101 111 101 0] [110 111 000 0] [111 100 000 0] [101 00_ 111 0] [ ___ ___ 1__ 0]

_ - this indicates that the bit is empty.i.e nothing has trnasmitted at that time.

ii. The transfer rate will be 900 kbps.

One frame = 10bits

frame rate = 900*10^3/10 = 90000 frames/s

iii.900kbs

iv.1/900000 = 1.1us

2.

i.Output frame size = 2*20 + 1 = 41

ii.20*100kbs / 41 = 48780 frames/sec

iii.1/48780 = 20.5 us

iv. 20 channels * 100kbs + 48780 framebits = 2.04878Mbs

v. total data bit = 2Mbs

efficiency = (2/2.04878 )*100 = 97.61 %

3.

i. As there is difference in transfer rates the lines with 40kps transfer rate will have to time slots in each frame.

so the total frame size = 1*2 + 2*3 = 8bits/frame (if one bit is taken from each frame)

ii. total data rate = 20kbs*2 + 40kbs * 3 = 160kbs

frame rate = 160kbs/8 = 20,000 frames

iii.1/20000 = 5 us

iv. Data rate will be same as 160kbs

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