Time division multiplexing

[sundarmeenakshi]

IN a Asynchronous TDM sysem out of 200 sources only 30 sources are active at a time as the input sources can generate data at a different rate, the time slots can have variable length of 1 nsec to 16 n sec. Calculate the over head bits added in every slot?

Dear friends any on can help to find the ans for this.

 

[A.Anand Srinivasan]

it depends on the system... they have a number of bits to identify the source and which in your case would be 7bits and if there are bits added for error correction then the number of overhead bits could be higher.... also a stream of bits are required to inform the receiver that the particular transmitter has finished transmitting...

 

[sundarmeenakshi]

it depends on the system... they have a number of bits to identify the source and which in your case would be 7bits and if there are bits added for error correction then the number of overhead bits could be higher.... also a stream of bits are required to inform the receiver that the particular transmitter has finished transmitting...

i think it is 5 bits.
n=log base2 to the power of 30.

 

[A.Anand Srinivasan]

you are supposed to have identity values for all the 200 sources because you dont know which 30 sources are transmitting currently....

 

[sundarmeenakshi]

you are supposed to have identity values for all the 200 sources because you dont know which 30 sources are transmitting currently....

then also 8 bits na?
this variable time slot has no effect in the no of bits? i need ans for tis also.

 

[A.Anand Srinivasan]

oh sorry... it is 8 bits only... i wrongly calculated using 120 sources.... actually overhead bits is the bits other than the message bits and this normally includes the source id, a sequence to denote the starting and stopping of transmission from a source since the transmission is asynchronous and also some error correcting codes....
the start and stop bits is compulsory since the transmission is asynchronous....