Re: Why TDM time slot time duration is 577us ??

Bit rate duration is determined from physical channel throughput for particular modulation schema. GMSK modulation is used with constant BT = 0.3, where  B is the 3dB bandwidth of the theoretical Gaussian filter and T is duration of input data bit. Knowing B, we calculate 1/T = 1625/6 ksymb/s  or approximately 270.833 ksymb/s. From here bit duration is 3.69.. μ s.

Voice signal is processed in time intervals of 20ms = s/50. For that period of time throughput is [(1625/6) x (1000/50)] symbols. Because this number is fractional, let look at 6 times longer time interval. For time interval 120ms throughput is [1625 x 20] symbols or [13 x 125 x 20] symbols or [26 x 1250] symbols or [26 x 8 x 156.25] symbols.