1 Scope
2
References
3
Application of ITU-T Recommendations on telephone performance to
national networks
4
National transmission plan
5
Attenuation distortion
6
Circuit noise
6.1 Noise induced by power lines
6.2 Noise contributed by transmission systems
6.2.1 Analogue systems
6.2.2 Use of companders to control noise on
analogue systems
6.2.3 Digital system
6.2.4 Mixed circuits
6.3 Noise in a national 4-wire automatic exchange
6.3.1 Analogue 4-wire automatic exchanges
6.3.2 Digital 4-wire automatic exchanges
6.4 Noise allocation for a national system
6.4.1 General planning assumptions
6.4.2 Noise allocations for planning digital
systems
6.4.3 Noise allocations for planning
incremental analogue transport systems
7
Error on the reconstituted frequency
8
Group-delay distortion
9
Linear crosstalk of circuits
10 Non-linear distortion of analogue
transmission systems
11 Variations of transmission loss
with time
Annex A – Noise allocation for a national system
A.5 Large countries