ETL600 1KHW001489-EN ABB Switzerland Ltd
∑
=
=
N
i
i
wS
1
.
(19)
The following remarks have to be made to this equation:
1. The S-value describes the signals to be transmitted by the system
while all active internal TPEs and all connected external TPEs are
in the guard-state (quiescent state).
2. Regarding the TPEs, the weights of the guard signals have to be
used.
3. A correction term w
corr
has to be added as explained later in section
5.2.16.2. Considering its effect on the S-value, this term can be
interpreted as an additional signal, which is however physically not
present.
The peak envelope levels of the contributions of the individual signals
at the RF connector are given by
[][]
⎟
⎠
⎞
⎜
⎝
⎛
∗+=
S
w
PEdBmLPEdBmL
i
RFi
log20
.
(20)
where L
RF
is the PEP of the aggregate RF signal.
5.2.12. Weight of the MOD600 signal
For a high datarate, the DPLC service needs a high SNR of 30 dB or
more. Thus a high weight should be given to the MOD600 signal. As a
consequence, most of the RF power would be given to the MOD600
signal, so that only little power would be left for the APLC signals,
resulting in low performance of the analog services. This problem is
avoided by specifying the MOD600 weight such that the level of the
MOD600 signal is always a fixed number of dB below the available RF
power. This leads to the following formula for the MOD600 signal
weight:
APLCADMOD
Svw
2600
,
(21)
where
S
APLC
= Sum of the weights of all signals in all APLC channels;
v
D2A
= DPLC to APLC weight factor.
The value of the factor v
D2A
is configurable by HMI600. The following
settings are possible:
MOD600 weight
setting =
low medium high proportional
V
D2A
= 1 2 3 min(3, B
DPLC
/B
APLC
)
Table 5-2 DPLC to APLC weight factor
where
B
DPLC
= Bandwidth of the DPLC channel;
B
APLC
= Sum of the bandwidths of all APLC channels.
Configuration and Set-up November 2005 5-9
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