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Splice‐induced impairments on very‐high‐speed digital data communications over copper telephone networks
Author(s) -
Sistanizadeh Kamran
Publication year - 1993
Publication title -
international journal of digital and analog communication systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.344
H-Index - 49
eISSN - 1099-1131
pISSN - 1047-9627
DOI - 10.1002/dac.4510060203
Subject(s) - splice , transceiver , crosstalk , insertion loss , computer science , physics , electronic engineering , electrical engineering , engineering , telecommunications , wireless , chemistry , biochemistry , gene
The effects of splice‐induced crosstalk, insertion loss and echo on very‐high‐speed digital data communications over copper telephone networks are analysed and evaluated. Sealing current is used to mitigate the adverse effects of the splices. The specifications of sealing current (i.e. magnitude, shape, frequency of application) have significant ramifications on the operations of the digital communication systems. For proper operation of echo‐cancellers (i.e. fast adaptation and tracking) on full‐duplex transceivers operating at 800 kbit/s, and to achieve a bit error ratio of 10 −7 , the magnitude and the rate of the change of splice fluctuations must be controlled. It is shown that the effects of crosstalk and insertion loss are not as severe as the occurrence of echo due to rapid fluctuations of splice impedance. The admissible ranges of splice fluctuations for a series of worst‐case scenarios are computed, and their effects on the performance of the echo‐canceller are discussed. If the splice fluctuation is restricted to 0·1 Ω on a 20 Ω splice, with the splice in the vicinity of the transceiver, the echo is —36 dB with respect to the far‐end received signal, which is an acceptable level on a 9 kft subscriber loop with an American Wire Gauge of 26. However, quantification of the dynamics (i.e. the rate of change) of splice fluctuations requires laboratory experiments and field measurements.