參數(shù)資料
型號： L64780
廠商： LSI Corporation
英文描述： DVB-T COFDM Demodulator(對地?cái)?shù)字視頻廣播 正交編碼頻率分割多路處理解調(diào)器)
中文描述： 的DVB - T COFDM解調(diào)器（對地?cái)?shù)字視頻廣播正交編碼頻率分割多路處理解調(diào)器）
文件頁數(shù)： 34/126頁
文件大?。?/td> 953K
代理商： L64780
2-16
Architectural Overview
PRBS generator) to obtain a snapshot of the response of the “channel”
(including any timing uncertainty) for the corresponding carrier at that
time instant.
The data cells that must be corrected lie between the scattered pilots, in
both frequency and time. This allows for appropriately generated
corrections for each data cell by using a suitable form of interpolation
applied to the measured values of the scattered pilots. As well as
obtaining “in-between” values of the channel response, the interpolator
also slightly reduces the effects of thermal noise on the scattered-pilot
measurements. The reduction in noise and the fact that scattered pilots
are transmitted with a power approximately 2.5 dB greater than data
cells, keeps the inevitable loss of performance due to scattered-pilot
noise within acceptable bounds.
2.11 Viterbi Metric Assignment and Quantization
This block takes in the sequence of complex numbers, each describing
the signal received on one of the COFDM carriers, after equalization.
These are the received versions of the complex numbers chosen at the
modulator from the points of the current constellation, according to the
coded bits to be sent. This block forms Viterbi metrics (“soft decisions”)
for each of the received bits. These metrics are quantized and passed
on, after reordering in the deinterleaver stages, to the associated Viterbi
convolutional decoder. The use of “soft” rather than “hard” decisions is
vital to obtaining the rugged properties of COFDM.
The associated Viterbi convolutional decoder, which resides on a
separate chip (for example, the LSI Logic L64724), is capable of
accepting soft decisions that are quantized to either three or four bits.
Three bits are required for acceptable performance, while four bits
improve the performance for higher-order modulation options of the DVB-
T specification, especially with non-uniform constellations. Decoder chips
designed primarily for QPSK or BPSK modulation commonly use three
bits because the advantage of using four bits is minimal.
The L64780 chip provides 4-bit soft decisions, but it also can be used to
drive 3-bit decoders.
相關(guān)PDF資料
PDF描述
L652DU12RE 128 Megabit (16 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory with VersatileIO⑩ Control
L652DU12RF 128 Megabit (16 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory with VersatileIO⑩ Control
L652DU12RI 128 Megabit (16 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory with VersatileIO⑩ Control
L652DU12RK 128 Megabit (16 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory with VersatileIO⑩ Control
L652DU90RF 128 Megabit (16 M x 8-Bit) CMOS 3.0 Volt-only Uniform Sector Flash Memory with VersatileIO⑩ Control
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L64781 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip COFDM Receiver
L64782 制造商:未知廠家 制造商全稱:未知廠家 功能描述:L64782 Single-Chip COFDM Receiver
L6480 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:The L6480, realized in analog mixed signal technology, is an advanced fully integrated solution suitable for driving two-phase bipolar stepper motors with microstepping.
L64801GC-20 制造商:未知廠家 制造商全稱:未知廠家 功能描述:32-Bit Microprocessor
L64801GC-25 制造商:未知廠家 制造商全稱:未知廠家 功能描述:32-Bit Microprocessor
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