CDR(Clock and Data Recovery) 电路的一些基本概念1

博客提及TI相关内容,探讨了时钟和数据恢复的概念,属于信息技术中硬件工程领域的知识。
标题 Method and apparatus for controlling a continuous time linear equalizer Method and apparatus for controlling a continuous time linear equalizer Circuits for and methods of robust adaptation of a continuous time linear equalizer circuit Continuous time linear equalizer with a programmable negative feedback amplification loop Methods and apparatus for continuous time linear equalizer tuning using decision feedback equalizer adaptation engine Continuous-time linear equalizer for high-speed receiving unit Adjusting a continuous time linear equalization-based receiver Adjusting a continuous time linear equalization-based receiver Continuous-time linear equalizer for high-speed receiving unit Continuous-time linear equalizer for high-speed receiving unit Continuous time linear equalization Methods and apparatus for a continuous time linear equalizer Adaptation Of A Linear Equalizer Using A Virtual Decision Feedback Equalizer (VDFE) Passive continuous-time linear equalizer Continuous-time linear equalizer for high-speed receiving unit Adaptation of a linear equalizer using a virtual decision feedback equalizer (VDFE) Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Method and apparatus for combining statistical eye channel compliance methods with linear continuous-time equalization Dual path double zero continuous time linear equalizer Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Apparatus and methods for equalizer adaptation Apparatus and methods for equalizer adaptation Passive continuous-time linear equalizer Dual-stage continuous-time linear equalizer Band-pass high-order analog filter backed hybrid receiver equalization Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Continuous time linear equalizer that uses cross-coupled cascodes and inductive peaking Continuous-time decision feedback equalizer Dual path double zero continuous time linear equalizer Transmitter Apparatus and Method Band-pass high-order analog filter backed hybrid receiver equalization Continuous-time decision feedback equalizer Transmit apparatus and method Dual path double zero continuous time linear equalizer Dual path double zero continuous time linear equalizer Dual path double zero continuous time linear equalizer Linear feedback equalization Integrated adaptive cable equalizer using a continuous-time filter Linear feedback equalization Receiver equalizer circuitry with offset voltage compensation for use on integrated circuits Low power delay buffer between equalizer and high sensitivity slicer Low power delay buffer between equalizer and high sensitivity slicer Adaptive continuous time linear equalizer Adaptive continuous time linear equalizer Adapting transfer functions of continuous-time equalizers High signal voltage tolerance in single-ended memory interface Methods and apparatus for adaptation of continuous time-decision feedback equalizers with programmable adaptation patterns Continuous-time equalizer Methods and apparatus for adaptation of continuous time-decision feedback equalizers with programmable adaptation patterns Adapting transfer functions of continuous-time equalizers Adaptive continuous-time line equalizer for correcting the first post-cursor ISI Adaptive continuous-time line equalizer for correcting the first post-cursor ISI Adaptive continuous-time line equalizer for correcting the first post-cursor ISI Apparatus and methods for equalizer adaptation Apparatus and methods for equalizer adaptation Circuit for and method of receiving an input signal Continuous time linear equalizer Continuous time linear equalizer Continuous time linear equalizer A CONTINUOUS-TIME FILTER AND EQUALIZER COMPRISING A PARASITIC-INSENSITIVE BiCMOS ACTIVE INTEGRATOR Equalizer circuit and control method of equalizer circuit Analog continuous-time phase equalizer for data transmission Analog Continuous-Time Phase Equalizer for Data Transmission Method and apparatus for passive continuous-time linear equalization with continuous-time baseline wander correction Low power passive offset injection for 1-tap decision feedback equalizer Transmitter apparatus and method Enhanced equalization based on a combination of reduced complexity MLSE and linear equalizer for heavily ISI-induced signals Enhanced equalization based on a combination of reduced complexity MLSE and linear equalizer for heavily ISI-induced signals Equalizer adjustment method, adaptive equalizer and memory storage device Communications receiver equalizer Methods and circuits for reducing clock jitter Linear flow equalizer for uniform polymer di
在串行通信中,SerDes(Serializer/Deserializer)技术用于将并行数据转换为串行信号进行传输,并在接收端恢复成并行数据。由于高速串行通信中时钟和数据通常不再通过独立的物理通道传输,因此需要使用 **时钟与数据恢复**(Clock and Data Recovery, CDR)模块来从接收到的数据流中提取时钟信息并正确采样数据。 ### 原理 CDR 的核心功能包括: 1. **时钟恢复(Clock Recovery)**: - 在没有单独时钟线的情况下,接收端必须从数据的边沿变化中提取出同步时钟。 - 这是通过锁相环(Phase-Locked Loop, PLL)或延迟锁定环(Delay-Locked Loop, DLL)实现的。 - 例如,在一个典型的基于PLL的CDR结构中,压控振荡器(VCO)会根据数据边沿的检测调整其频率,以匹配发送端的时钟频率[^1]。 2. **数据恢复(Data Recovery)**: - 一旦恢复了时钟信号,就可以使用该时钟对输入的数据进行采样。 - 数据恢复的关键在于确定最佳采样点,通常是在数据眼图的中心位置,以避免由抖动、噪声和信道失真引起的误码。 ### 实现方法 1. **基于相位插值的CDR**: - 使用多个相位不同的时钟信号,通过插值选择最合适的采样时点。 - 控制逻辑会根据数据的边沿信息不断调整插值相位,以保持最佳采样点。 2. **基于数字反馈控制的CDR**: - 利用数字控制器(如有限状态机)监测数据边沿与当前采样时钟之间的关系。 - 根据检测结果动态调整采样时钟的相位,以维持同步。 3. **超采样CDR(Oversampling CDR)**: - 使用远高于数据速率的时钟对数据进行多次采样。 - 然后从中选择最可靠的采样点作为有效数据。 4. **UCIe中的特殊处理**: - UCIe(Universal Chiplet Interconnect Express)标准不依赖传统的CDR机制,而是提供了一对前向时钟线。 - 接收端不需要恢复时钟,只需进行数据训练(Data to Clock Training),以确保数据与时钟对齐[^2]。 ### 示例代码:简单的CDR模拟(基于Python) 以下是一个简化的CDR行为模型示例,用于演示如何在仿真环境中对数据进行采样点调整: ```python import numpy as np def cdr_recovery(data_stream, ref_clock_freq, data_rate): # 模拟CDR过程,假设已知参考时钟频率和数据率 oversample_factor = int(ref_clock_freq / data_rate) samples = np.array(data_stream) recovered_data = [] for i in range(0, len(samples), oversample_factor): window = samples[i:i+oversample_factor] best_sample_index = i + np.argmax(np.abs(window)) # 找到最大绝对值的位置作为最佳采样点 recovered_data.append(samples[best_sample_index]) return recovered_data # 示例数据流(模拟带有抖动的二进制信号) data_stream = [1 if np.sin(2*np.pi*i/16) > 0 else 0 for i in range(128)] recovered = cdr_recovery(data_stream, ref_clock_freq=1e9, data_rate=125e6) print("Recovered Data:", recovered[:10]) # 显示部分恢复数据 ``` ###
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