Product Technical Bulletin
Model 2809
CATV
Linx
®
LDS CATV Receiver
4
Revision 2.0
4) Figure 1.4 shows the RF output behavior of the 2809 receiver. The blue line
shows the nominal Rf output level versus optical input. Over the optical input
range from -8 dBm to +4.5 dBm, the RF output level varies by 2 dB for every
1 dB drop in optical input power. Operating below -8 dBm optical input will
cause the CNR to degrade rapidly for channel loads of 77 or more.
Figure 1.4 RF Output Level Behavior of 2809R
In Figure 1.4 the central green area is the region that should be used for new
designs. So while the receiver is rated to optical input powers as low as -8
dBm, it is recommended that -6 dBm be the minimum for a newly installed
system. That leaves 2 dB of margin for the optical power to drop and still pro-
vide good operation. The yellow region is the safety band. The unit is rated to
operate in this region; however, the margin will probably be inadequate for a
newly installed design. The red regions are outside the recommended operat-
ing parameters of the 2809R and must be avoided to ensure reliable opera-
tion.
5)
This product must be used only with APC type optical connectors or
fusion spliced connections.
There is some folklore which suggests that the
only critical backreflection is the one closest to the transmitter. Our experience
does not support that view. We find that
all
backreflections matter, regardless
of their distance from the transmitter.
6) Force, Inc. recommends using the Model PS095 wall-mount power supply
(see TB043) with the Model 2809 receiver.
7) Most parameters are relatively unaffected by varying temperature. A moving
air environment is recommended at ambient temperatures above +35°C.
8) Humidity is RH non-condensing.
9) The
CATV
Linx
®
LDS CATV receiver is optimized for single-mode operation only.
Use on multimode fiber is not recommended, even for short distances,
because of the large amount of modal noise that could result.
-10
-2
0
2
4
6
8
10
RF Output Level (dBmV/Channel)
12
14
16
18
20
22
24
26
28
30
-8
Optical Input (dBm)
-6
-4
-2
0
2
4
6
