User's Manual

Innovator CU0TD-1/CU0RD-1 – CU4TD/CU4RD 8VSB ATSC Modulator
ATSC Transmitter/Regenerative Translator
Instruction Manual, Rev. 2 52
Digital Adaptive Pre-corrector
The Digital Pre-corrector page allows the user to configure the capture card cycle
(adaptation process) settings and store the NLP and/or LP Profiles (coefficients) into
memory.
Pre-correction Set-up
The user should first select which pre-correction cycles will be run by configuring the
“NLP/LP Selection” parameter. The user may select Non-linear Pre-correction (NLP),
Linear Pre-correction (LP) or both. The user should also select how many NLP cycles will
run for every LP cycle. When the modulator is synchronized with a 1PPS reference
signal (from a GPS receiver), the user can offset the cycle start time, relative to the
1PPS signal.
Note: The NLP cycle will always run before the LP cycle when both cycles are selected.
The user must then select the “NLP Method” to determine which pre-correction algorithm
is used. The user should first try “Regression” mode. If the results are undesirable, the
user should then try “RLS” mode, then “Legacy” mode.
The user must then select the “Mode” parameter and set the “Precorrection” parameter
to “Run” to start the cycle(s) (adaptation process). When the “Mode” parameter is set
to Adaptive, the NLP and/or LP coefficients will be optimized constantly. When the
“Mode” parameter is set to “Single Operation”, the NLP and/or LP coefficients will only be
optimized once.
If the “Precorrector” parameter is set to “Stop”, the NLP and/or LP cycles will stop, with
the last calculated coefficients being used. In other words, the cycle(s) will stop, but the
Non-linear Pre-correction and/or Linear Pre-correction will not be disabled. To disable
the pre-correction, the “Precorrection” parameter must be set to “Stop” and “Reset
Precorrector” must be set to “ON”. Setting “Reset Precorrector” to “ON” while the
cycle(s) have stopped will clear the NLP and LP coefficients.
Note: Any time a parameter is changed (i.e from NLP to NLP/LP) the user should first
Stop the Precorrection then Reset the Precorrection prior to changing the parameter.
This excludes saving NLP or LP profiles.
Storing a Profile (Curve) to Memory
To store the active Profile (coefficients) to memory, the user must set “Save Adaptive
NLP Profile” or “Save Adaptive LP Profile” to “ON”. Before saving, the user should
configure the “Profile Name” and “Profile Number” accordingly.
Loading a Profile (Curve) from Memory
A NLP or LP Profile can be loaded from memory using the Non-linear or Linear Pre-
corrector pages – see the Non-linear and Linear sections. The user must select the
desired profile from the NLP or LP Profile pull-down menu and ensure that the NLP or LP
State is set to “ON”.