zl10354 Zarlink Semiconductor, zl10354 Datasheet - Page 14

• Manufacturer Part Number: zl10354
• Description: Diversity Enabled Nordig Unified Dvb-t Cofdm Terrestrial Demodulator For Pc-tv And Hand-held Digital Tv Dtv
• Manufacturer: Zarlink Semiconductor

2.9
This module subtracts the common phase offset from all the carriers of the OFDM signal to minimize the effect of
the tuner phase noise on system performance.
2.10
This consists of two parts. The first part involves estimating the channel frequency response from pilot information.
Efficient algorithms have been used to track time-varying channels with a minimum of hardware.
The second part involves applying a correction to the data carriers based on the estimated frequency response of
the channel. This module also generates dynamic channel state information (CSI) for every carrier in every symbol.
2.11
ZL10354 contains several mechanisms to reduce the impact of impulse noise on system performance.
2.12
An OFDM frame consists of 68 symbols and a superframe is made up of four such frames. There is a set of TPS
carriers in every symbol and all these carry one bit of TPS. These bits, when combined, include information about
the transmission mode, guard ratio, constellation, hierarchy and code rate, as defined in ETS 300 744. In addition,
the first eight bits of the cell identifier are contained in even frames and the second eight bits of the cell identifier are
in odd frames. The TPS module extracts all the TPS data, and presents these to the host processor in a structured
manner.
2.13
When two or more ZL10354s are combined in a chain using their diversity buses, the first stage chip operates in the
normal way on a single tuner source, however the channel-corrected OFDM data are output to the next device in
the chain. This ZL10354 combines the received diversity data with the channel-corrected data from its own OFDM
demodulation process, selecting the optimum data from each source for any given carrier. The resulting data are
either passed to another ZL10354 for further combining, or the FEC logic to generate an MPEG transport stream.
2.14
This module generates soft decisions for demodulated bits using the channel-equalized in-phase and quadrature
components of the data carriers as well as per-carrier channel state information (CSI). The de-mapping algorithm
depends on the constellation (QPSK, 16QAM or 64QAM) and the hierarchy ( = 0, 1, 2 or 4). Soft decisions for both
low- and high-priority data streams are generated.
2.15
The OFDM transmitter interleaves the bits within each carrier and also the carriers within each symbol. The
de-interleaver modules consist largely of memory to invert these interleaving functions and present the soft
decisions to the FEC in the original order.
Common Phase Error Correction
Impulse Filtering
De-Mapper
Channel Equalization
Transmission Parameter Signalling (TPS)
Diversity Optimizer
Symbol and Bit De-Interleaving
Zarlink Semiconductor Inc.
ZL10354
14
Data Sheet