Transmitter Setup
4–2
Copyright © 2006 Harmonic Inc.
4.1
Factory-Optimized Settings
The Harmonic factory optimizes the performance of each model in the
PWL 4100S series prior to shipment. The factory setup is listed in Table 4-1.
The Harmonic factory-optimized setup procedure balances:
•
CNR (carrier-to-noise) performance
•
CSO (composite second order) distortion performance
•
CTB (composite triple beat) distortion performance
Once the Harmonic factory optimizes a PWL 4100S transmitter, the factory
settings are written into the transmitter’s memory. These settings allow the
transmitter to achieve the performance given in Appendix A at factory setup
for any model in the PWL 4100S series of transmitters.
These factory settings include:
•
Internal RF pad value
(user adjustable)
•
Laser bias
(not user adjustable)
•
Laser current
(not user adjustable)
•
Laser temperature
(not user adjustable)
•
Others
4.1.1
Returning to Factory Settings
If at any time the transmitter’s settings are changed, you can always return
the transmitter to the original factory settings through the HLP 4200WD
display interface. In the Transmitter Adjustments menu, select the Return to
Factory Settings option. Follow the procedure in Section
Transmitter to Factory Defaults
When the transmitter reverts to the factory-optimized settings:
•
If the transmitter is in AGC mode, the internal RF pad level automatically
adjusts to get the adequate drive level to the laser for optimized
performance.
•
If the transmitter is in MGC mode, the transmitter reverts to factory
settings based on Table 4-1, regardless of the actual RF input level. For the
best performance, you must adjust the input level to 15 dBmV per
channel. For instructions, see Section
4.4.2 Fine-Tuning the Transmitter
Table 4-1:
Factory Setup
Loading
80 unmodulated System M (NTSC) channels from 45 to 550 MHz;
450 MHz digital information above 550 MHz -6 dBc down from
analog channels
RF input level
+15 dBmV per video channel
Link loss
100% fiber link (example: PWL 4115S is tested over 15 dB of fiber)
Harmonic
receiver
HRM 3811
