Question

A multiplexer combines four 100-kbps channels using a time slot of 2 bits. what is the bit rate ?

Answer 1

The link carries 50,000 frames per second.

The frame duration is therefore 1/50,000 s or 20 μs.

The frame rate is 50,000 frames per second, and each frame carries 8 bits; the   bit rate  is  50,000 ×  8  =  400,000  bits  or  400  kbps.

Answer 2

" The total bandwidth for the given input channels is calculated as $100 \times 1000 \times 4$bits per second.

Hence, the transmission time for all the 4 channels in the 2 bit slot will be given as$\frac { 2 }{ \left( 100\quad \times \quad 1000\quad \times \quad 4 \right)}$ and it results as 0.000005 ms.

         So, for 1 sec how many bits will get transferred is the question and it can be found using $\frac { 1 }{ \left( 0.000005\quad \times \quad 2 \right)}$bits per second. When solving this, we get the answer as 400 Kbps."