如今电脑接口速率不断提升，从USB3.0的5Gbps，到现在USB4 V2的 40Gbps。速率提升的同时，也带来了信号在信道中过度损耗的问题。信号补偿成了现在系统设计的难题。各大厂商都陆续推出自家的信号补偿芯片。Re-driver，Re-timer，Repeater也高频率出现在工程师的耳边。今天，我们结合USB规范里面定义的Re-driver, Re-timer, Repeater术语来介绍下。
Re-driver :
『Re-driver refers to an analog component that operates on the signal without re-timing it. This may include equalization, amplification, and transmitter. The re-driver does not include a clock-data recovery (CDR) circuit. 』
Re-timer :
『Re-timer refers to a component that contains a clock-data recovery (CDR) circuit that “retimes” the signal. The re-timer latches the signal into a synchronous memory element before re-transmitting it. It is used to extend the physical length of the system without accumulating high frequency jitter by creating separate clock domains on either side of the re-timer. 』
Re-driver：
中文翻译重驱动器，其内部核心电路是一个可调谐的时域均衡器，时域均衡器的加入可以改善系统频率响应特性，来补偿模拟信号的响应失真。通常也会叫做移除信道中的码间串扰ISI (Inter-Symbol Interference)。
Re-timer：
中文翻译重定时器，在重驱动器基础上面增加信号时钟恢复模块。均衡器只能补偿模拟信号在信道上的频率响应失真,而无法处理信号的时钟抖动。而对于更高频率信号，意味着更少的timing margin，例如5Gbps速率，UI是200皮秒，最小眼图宽度70皮秒。10Gbps信号速率，UI是100皮秒，最小眼图宽度减少到35皮秒。所以通常大于5Gbps信号的场合会有需要加入时钟恢复模块，方便系统顺利通过CTS（Compliance Test Specification）。
Repeater :
『Repeater refers to any active component that acts on a signal in order to increase the physical lengths and/or interconnect loss over which the signal can be transmitted successfully. The category of repeaters includes both re-timers and re-drivers. 』
Repeater：
中文翻译中继器，Repeater包含了Re-driver和Re-timer，通常我们可以称Re-driver Repeater 和 Re-timer Repeater。
附 Diodes 电脑端接口产品介绍
|
Interface |
Diodes P/N |
SPEC |
|
USB4 |
PI2DPT2021 |
ReTimer USB4 / UHBR10 |
|
USB C |
PI2DPT1021 |
ReTimer / USB3.2 Gen2*2 / DP1.4 HBR3 |
|
USB C |
PI3DPX1207 |
ReDriver / USB3.2 Gen2*2 / DP1.4 HBR3 |
|
USB C |
PI2DPX1066 / 1217 |
ReDriver / USB3.2 Gen2*2 / DP2.0 UHBR10 |
|
USB C |
PI2DPT821 |
ReTimer / USB3.2 Gen1*2 / DP1.4 HBR3 |
|
USB A |
PI3EQX1002 |
ReDriver / USB3.2 Gen2 |
|
HDMI2.0 |
PI3HDX1204 |
ReDriver / HDMI 2.0 |
|
HDMI2.1 |
PI3HDX12211 |
ReDriver / HDMI 2.1 |
『』作者：USB IF；出处：Universal Serial Bus Type-C Cable and Connector Specification
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