Appendix B
Characteristics of the PDH system.
Characteristics
E1
T1
a Sampling frequency
8000 Hz
8000 Hz
b Number of samples per
telephone signal
8000 per second
8000 per second
c Length of PCM frame
1/b=1/8000/s=125
µ
s 1/b=1/8000/s=125
µ
s
d Number of bits in each code
word
8 8
e Telephone channel bit rate
b x d=8000/s x 8 bit
= 64 kbit/s
b x d=8000/s x 8 bit
= 64 kbit/s
f Encoding/decoding
Number of segments in
characteristic
A-law
13
µ
-law
15
g Number of timeslots per
PCM frame
32 24
h Number of bits per PCM
frame
d x g = 8 x 32
= 256 bits
d x g + 1 = 8 x 24 +
1 = 193 bits
i Length of an 8 bit timeslot
(c x d) / h
(125 us x 8) / 256
approx. 3.9
µ
s
(c x d) / h
(125 us x 8) / 193
approx. 5.2
µ
s
j Bit rate of time-division
multiplexed signal
b x h
8000/s x 256 bits
2048 kbit/s
b x h
8000/s x 193 bits
1544 kbit/s
