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| 型号： | IPR-VITERBI/HS |
| 厂商： | Altera |
| 文件页数： | 5/50页 |
| 文件大小： | 0K |
| 描述： | IP VITERBI HIGH-SPEED RENEW |
| 标准包装： | 1 |
| 系列： | * |
| 类型： | MegaCore |
| 功能： | Viterbi 高速编译器 |
| 许可证： | 续用许可证 |
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1. About This Compiler
This document describes the Altera ? Viterbi Compiler. The Altera Viterbi Compiler
comprises high-performance, soft-decision Viterbi MegaCore functions that
implement a wide range of standard Viterbi decoders.
Viterbi decoding (also known as maximum likelihood decoding or forward dynamic
programming) is the most common way of decoding convolutional codes by using an
asymptotically optimum decoding technique. In its basic form, Viterbi decoding is an
efficient, recursive algorithm that performs an optimal exhaustive search.
A convolutional encoder and Viterbi decoder can be used together to provide error
correction over a noisy channel, e.g., a communications channel. A convolutional
encoder adds redundancy (i.e., extra bits) to a data stream before transmission.
The rate and the generating polynomials describe the convolutional code, hence they
describe the convolutional encoder. The rate is the number of transmitted bits per
input bit, e.g., a rate 1/2 encodes 1 bit and produces 2 bits for transmission. Similarly,
a rate 2/3 encodes 2 bits and produces 3 bits for transmission. A code can be
punctured to increase its rate, by deleting some of the encoded bits according to a
deterministic pattern.
The generating polynomials denote the convolutional encoder state bits, which are
mathematically combined to produce an encoded bit. There is one generating
polynomial per encoded bit. The length in bits of the generating polynomial is called
the constraint length; systems with higher constraint lengths are generally more
robust. However, the complexity of the Viterbi decoder increases exponentially with
the constraint length, so it is unusual to find constraint lengths greater than nine.
A noisy transmission channel causes bit errors at the receiver. The Viterbi algorithm
finds the most likely sequence of bits that is closest to the actual received sequence.
The Viterbi decoder uses the redundancy, which the convolutional encoder imparted,
to decode the bit stream and remove the errors.
The receiver can deliver either hard or soft symbols to the Viterbi decoder. A hard
symbol is equivalent to a binary ±1. A soft symbol is multi-leveled to represent the
confidence in the bit being positive or negative. For instance, if the channel is non-
fading and Gaussian, the output of a matched filter quantized to a given number of
bits is a suitable soft input. Punctured symbols are indicated with the eras_sym input.
The Viterbi algorithm has better performance with soft input symbols.
The Viterbi decoder works on blocks of data, or continuous streams. It takes in N
symbols at a time for processing, where N is the number of encoded symbols. The
traceback length is the number of trellis states processed before the decoder makes a
decision on a bit.
Features
The Viterbi Compiler provides two high-performance, area-optimized, soft-decision
Viterbi decoder MegaCore functions—the hybrid and parallel architecture. For both
MegaCore functions, you can specify the BER estimator, node synchronization, and
multiple code sets (including the variable constraint lengths).
November 2013
Altera Corporation
Viterbi Compiler
User Guide
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相关代理商/技术参数 |
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| IPR-XAUIPCS | 功能描述:开发软件 10G Ethernet Phy MegaCore RoHS:否 制造商:Atollic Inc. 产品:Compilers/Debuggers 用于:ARM7, ARM9, Cortex-A, Cortex-M, Cortex-R Processors |
| IPS0151 | 功能描述:IC MOSFET PWR SWITCH TO-220AB RoHS:否 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 内部开关 系列:- 标准包装:1,000 系列:- 类型:高端/低端驱动器 输入类型:SPI 输出数:8 导通状态电阻:850 毫欧，1.6 欧姆 电流 - 输出 / 通道:205mA，410mA 电流 - 峰值输出:500mA，1A 电源电压:9 V ~ 16 V 工作温度:-40°C ~ 150°C 安装类型:表面贴装 封装/外壳:20-SOIC（0.295"，7.50mm 宽） 供应商设备封装:PG-DSO-20-45 包装:带卷 (TR) |
| IPS0151PBF | 制造商:International Rectifier 功能描述:MOSFET SMART SWITCH TO-220 |
| IPS0151S | 功能描述:IC MOSFET PWR SWITCH D2PAK RoHS:否 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 内部开关 系列:- 标准包装:1,000 系列:- 类型:高端/低端驱动器 输入类型:SPI 输出数:8 导通状态电阻:850 毫欧，1.6 欧姆 电流 - 输出 / 通道:205mA，410mA 电流 - 峰值输出:500mA，1A 电源电压:9 V ~ 16 V 工作温度:-40°C ~ 150°C 安装类型:表面贴装 封装/外壳:20-SOIC（0.295"，7.50mm 宽） 供应商设备封装:PG-DSO-20-45 包装:带卷 (TR) |
| IPS0151S | 制造商:International Rectifier 功能描述:MOSFET SMART SWITCH D2-PAK |
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