Link Performance; Figure 3-9 Sg2-87 Low-Gain Output-Stage Pad-Effects Chart - Motorola Starline SG 2000 Installation And Operation Manual

Figu r e 3- 9
SG 2- 87 low - g ain out p ut - st ag e pad - ef f e ct s ch art
80.00
75.00
70.00
65.00
60.00
55.00
50.00
45.00
40.00
38 39 40
L i n k P e r f o r m a n c e
The SG 2000-* link performance charts are meant as a guide to assist you when working with
varying link parameters. The link is defined as beginning at the transmitter RF input and ending at
the RF output jack on the SG2-LR optical receiver. These charts show the effects of changes in fiber
loss and receiver optical power input on c/n, CTB, and composite second order (CSO).
The particular curve along which incident optical power should be equated to c/n is determined by
the fiber loss budget in the system. This must only include fiber loss; no connector or splitting losses
should be included in this number. Because these curves require knowing only the fiber loss and the
received optical power, transmitter power is not a factor. The transmitter is assumed to have a
relative intensity noise (RIN) of –158 dB/Hz.
Figures 3-10 and 3-11 illustrate the distortion curves and show the changes in CTB and CSO that can
be expected at higher optical inputs. These charts assume transmitter CTB of –66 dBc and CSO of
–62 dBc for 77 channel loading. For 110-channel loading, the transmitter assumptions are –64 dBc
CTB and –61 dBc CSO.
41 42 43 44 45
Output Level (Highest Analog), dBmV - 11.5 dB Tilt
B e n c h S e t u p
46 47 48 49
S G 2 0 0 0 I n s t a l l a t i o n a n d O p e r a t i o n M a n u a l
3 - 1 5
-80.00
-75.00
-70.00
CNR-10
-65.00
CNR-6
CNR-3
CNR-0
-60.00
CTB-0
CTB-3
CTB-6
-55.00
CTB-10
-50.00
-45.00
-40.00
50