Ericsson DIALOG - Dialog Telephone Dismantling and Reassembly

--Exel cableottenuat1on
-- E~cl cobleottenuot1on
--- Incl cable att enuation
- - - Incl coble attl'11Uot1on
Cables O.l. mm. r • 280 • l.O nF /km o<. • l.62 dB /km
0,5 mm r .. 180 c = 40 nF /km :x = 1,22 dB /km
Cables G,l. mrn. r =280n/km,c=l.0 nF =1,62 dB/km
0.6 rnm r = 125 c =40 nF /km a; x 0,95 dB /km
0.5mm.r=l80 c-l,OnF =1,22dB/km
0.6 mm. r =125 C=lO nF oo:.~0.95 dB/km
dB R e ce1v1~ Rl"'ference Equival e nt rel to NOSFER
-10
SRE
-----------RRE
•10
I
I
uoL __ _
----+--- ________ ___,
•IC+--------+--
0 500 1000 1500 ohm
500
1000 1500 ohm
~------r---- - - ---+-------+-----+-----+
0 1 2 5 km Ol. mrr!
5 kn1 0.4 mni
~-~--------t-------+-------·-----t---+-----
2 3 l, 5
f--- - t------+----+-
~
--~
0 1 2 1 4
J 8 9
10
Fig. 37
11
8 km 0 Smm
8 km 0.5 mm
km 06 mm
~--+----+--+---+-~~-~r --+----------+----+-----------
.R 9 10 11 km 0,6rnm
Fiz. 38
In fig. 37 - 38 sending and receiving reference equivalents for the
instrument as a function of the line resistance, and cable attenu-
ation, are given. The sending reference equivalent, SRE, is
practically independent of the line resistance, while the receiving
reference equivalent, RRE is improved in the increased line
resistance up to about 1 000 Ohm. At 1 000 Ohm the effect is
about 4 dB higher than at 0 Ohm.
Since SRE, without cable attenuation, is practically constant, a
curve with SRE as a function of the line length, inclusive cable
attenuation, will naturally vary with the latter. This point is
also illustrated in fig. 37, which represents the function produced
for three different cable dimensions. In an instrument without
regulation the slope of the curve would naturally be steeper, since
attenuation has to be added owing to the reduced transmitter
feeding.
The receiving level as function of increased line resistance,
shown in fig. 38, is reduced, when cable attenuation is included.
The result is a flattened curve, which means almost constant
receiving level within the range 0 - 1 000 Ohm line resistance. The
difference shown by cables with small cable diameter is of course
dependent on the high resistance per km. The ideal is a regulation
which completely compensates cable attenuation. Since cable types
vary, the design of Dialog is a compromise, with the best possible
values for common types of cables.
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