Specifications

8-VSB Agile Modulator Issue 1.02 December 9, 2008 Page 17 of 29
www.technalogix.ca
Output Interface Management
Channel Encoding:
The modulator performs channel encoding according to the ATSC standard:
- Randomization (energy dispersal)
- Reed Solomon coding (RS coding)
- Data field interleaving
- Trellis coding (constellation building)
Channel Modulation:
The modulator performs channel modulation according to the ATSC standard:
- Frame building
- Pilot insertion
- Constellation mapping
- Nyquist filter
Output Processes
Linear pre-correction
The modulator can perform linear pre-correction adjustment. It is possible to
configure the amplitude and group delay values. The group delay correction is
from -2 to +2μs while the amplitude adjustment is +/- 3dB. A Tilt function has
been implemented to correct for up-converter distortions. It uses a set of 64
coefficients that are computed by the control software.
Using the software, the user will define their linear pre-correction curve. Then the
points will be used to compute complex coefficients to be sent to the module. It
needs 64 complex coefficients and these coefficients are used in the module to
configure the filter.