1. . Why has the PCM sampling time been set at 125 µsec? 2. . What is the percent overhead on a T1 carrier? That is, what percent of the 1.544 Mbps are not delivered to the end user? How does it...

1. . Why has the PCM sampling time been set at 125 µsec?

2. . What is the percent overhead on a T1 carrier? That is, what percent of the 1.544 Mbps are not delivered to the end user? How does it relate to the percent overhead in OC-1 or OC-768 lines?

3. Compare the maximum data rate of a noiseless 4-kHz channel using (a) Analog encoding (e.g., QPSK) with 2 bits per sample. (b) The T1 PCM system.